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March 25–28, 2023

CNS 2023 Annual Meeting | Data Blitz Session Schedule

Data Blitz Sessions

What is a Data Blitz? A Data Blitz is a series of 5-minute talks, each covering just a bite-sized bit of research. It will offer a fast-paced overview of some of the most exciting research presented at this year's poster sessions.

Within the submissions process authors submitting an abstract will have the option of checking a box to indicate whether they’d like their abstract to be considered for the Data Blitz Session. Selected abstracts will then be scheduled into the Data Blitz session in addition to a poster session. Talks will be given by the abstract first author — a faculty member or student at any level. Accepted presenters will then be asked to prepare a concise, 5-minute video for the session.

Each DataBlitz session includes 15-5 minute talks with an additional 30-minute live Q&A following. Be sure you are available for the Q&A directly after your DataBlitz session.

 

Session # Date Time Location Chair
Data Blitz Session 1 Saturday, March 25 12:00 – 1:30 pm Grand Ballroom A TBA
Data Blitz Session 2 Saturday, March 25 12:00 – 1:30 pm Grand Ballroom B/C TBA
Data Blitz Session 3 Saturday, March 25 12:00 – 1:30 pm Bayview Room TBA

 

Data Blitz Session 1

Saturday, March 25, 12:00 – 1:30 pm, Grand Ballroom A

Chair: TBA

Speakers: Carola Salvi, Abigail Hsiung, Benjamin Rangel, Noah Reardon, Yuxi Candice Wang, Miriam Taza, Sneha Sheth, Gaelle Doucet, Hai-Tao Wu, Jennifer Crawford, Jacob Miller, Jonathan Daume, Gayathri Satheesh, Thomas Biba, Damiano Grignolio

 

TALK 1: Aha! Experiences enhance learning for incidental information. New evidence supporting the insight memory advantage.

Carola Salvi, University of Texas at Austin - John Cabot University of Ro

Research on creative problem solving finds that solutions achieved via spontaneous insight (i.e., Aha! moment) are better remembered than solutions reached without a sense of epiphany, referred to as an 'insight memory advantage.' We hypothesized that the insight memory advantage can spread to incidental information encoded in the moments surrounding spontaneous insight as well. Participants (N= 291) were presented with incidental scholastic facts, unrelated to the problem, immediately after indicating they reached a solution to a word problem (i.e., Rebus Puzzles), but prior to entering the answer. Participants indicated whether they reached the solution via either insight or a step-by-step analysis. Memory results showed better performance for incidental scholastic facts presented when problem solving was accompanied by a spontaneous insight (Aha!) compared to solutions reached without an Aha! moment. This finding suggests that the memory advantage for problems solved via insight spreads to other unrelated information encoded close in time. These findings have implications for enhancing learning and memory retention by incorporating unrelated information in temporal proximity to insight-based problem solving.

TALK 2: Spoiler Alert! Curiosity prioritizes the information gathering process over the outcome

Abigail Hsiungi, Duke University

Curiosity, the desire to know, is a fundamental motivator of human behavior. Current theoretical accounts posit that curiosity directs information seeking choices towards the resolution of uncertainty. Yet in everyday life, we often prolong uncertainty, for example avoiding spoilers for just-released movies. We investigated whether states of high curiosity favor delaying resolution to experience an event as it unfolds. We developed a novel video task in which line drawings slowly resolved into objects. As each video progressed, participants made choices about how long to keep watching. Across two studies that varied in the amount of agency allotted to participants, we showed that when curious, participants often choose to remain uncertain as information is gradually revealed, rather than alleviate uncertainty immediately (i.e., viewing a spoiler). Across studies, we found that allowing participants to titrate their information sampling experience emphasized the importance of self-determined resolution. The ability to precisely control timing increased the likelihood of stopping a video early but only when participants correctly reported the identity of the drawing. The choice to prolong uncertainty also benefitted the information gathering experience, promoting enhanced feelings of satisfaction, and improving memory for the drawing in the video. Our findings reveal that curiosity not only confers value to information itself, but also influences preferences for how one arrives at that information, highlighting the reward value inherent in the process of discovery as an important factor for curiosity and memory formation.

TALK 3: Surprise-induced inhibition of active task set representations

Benjamin Rangel, University of Iowa

Simple tasks, such as opening your front door, involve multiple neural representations - the external situation (your house/door), the associated actions (insert/twist key & twist knob), and the expected outcome (door opens). These lower representations are purportedly combined into higher-order, conjunctive representations (opening your front door), which are stored and retrieved at later times to facilitate repeated behaviors. Previous research has demonstrated that such conjunctive representations are also retrieved when the situation or context is similar but not identical, resulting in the preparation or execution of inappropriate actions - and hence a 'partial-repetition cost' (PRC, e.g., reaching for your key at your friend's front door; Rangel et al., JNeuro 2022). Here, we used the PRC to test whether surprising, task-unrelated events, prior to the response, can inhibit the formation or later retrieval of conjunctive representations. Surprising events are known to inhibit active working memory contents (Wessel et al., Nature Communications 2016), and we hypothesized that this may include task sets. Forty-five adult humans performed a task-switching paradigm while undergoing EEG recordings, which we used to decode neural signals indexing conjunctive task set representations (Kikumoto & Mayr, PNAS 2020). In line with prior work, the partial repetition of task set features between two spaced trials lead to a deficit on reaction time. However, this PRC was completely abolished when a surprising event occurred after the formation of the initial task set's conjunctive representation. This suggests that surprising events can inhibit the strength of active task sets, and consequently their retrieval.

TALK 4: Incidental Exposure Optimizes Attention to Features that are Relevant to Category Membership

Noah Reardon, The Ohio State University

Categories simplify and help us interact with our environment. Most research on category learning has explicitly taught categories and found that adults selectively attend to the smallest number of features that determine category membership. However, much exposure to real-world categories occurs incidentally, without an explicit intention to learn. Moreover, categories are typically associated with clusters of features that occur together; for example, trees tend to have a trunk, branches, and leaves. Recent evidence suggests that incidental exposure improves subsequent category learning from explicit teaching. One explanation for this may be that attention is drawn to features that cluster together and are thus relevant to category membership. To test whether incidental exposure optimizes attention to relevant features, we tasked participants with learning to categorize unfamiliar creatures. Category membership depended on the appearance of a cluster of 'relevant' features. Critically, before this task, participants were exposed to the creatures during a simple game in either an Incidental condition, in which they saw creatures belonging to two categories, or a Baseline condition, in which they saw randomized creatures. Eye tracking was used to examine attention to irrelevant versus relevant features. Results suggest that participants in the Incidental condition began attending to relevant features during the exposure phase. Moreover, those who continued paying attention to these features excelled at category learning. In contrast, Baseline participants gradually refocused their attention to relevant features after being explicitly taught categories. This study provides evidence that incidental exposure optimizes attention to features that are relevant to category membership.

TALK 5: Target detection does not influence temporal memory

Yuxi Candice Wang, Duke University

Target detection has been found to enhance subsequent memory for concurrently presented stimuli under dual-task conditions. This phenomenon, the 'Attentional Boost Effect,' has been generalized across a variety of memory tests, including item recognition memory, source memory, and memory for task-irrelevant stimulus features. One interpretation is that the detection of a target constitutes an event boundary that enhances perceptual processing of concurrently presented information, analogous to the source memory enhancement effect for boundary items. In support of this idea, prior research has found locus coeruleus activity-related phasic pupil response to be associated with both target detection and event segmentation. Like event boundaries that require an update of working memory event representations or an update of task goals, responding to a target (either an overt response like a button press or a covert response like increasing a mental count) also requires working memory update. Though there are important parallels between the Attentional Boost Effect in target detection and event segmentation studies, whether target detection also impacts temporal memory in similar ways as event boundaries remains unknown. We investigated this question in a pre-registered experiment with sequential Bayes factor design by inserting targets and distractors during encoding of trial-unique object images, then comparing subsequent temporal order and distance memory for image pairs that span a target or distractor. We found that target detection enhanced recognition memory for target-concurrent images but had no effect on temporal memory. These results suggest that target detection does not disrupt inter-item associations in memory like event segmentation.

TALK 6: Age-Related Differences in the Relationship Between the Basal Forebrain Volume, Functional Connectivity, and Cognition

Miriam Taza, McGill University

The basal forebrain (BF) comprises large cholinergic projection neurons that innervate the entire cortical mantle. Acetylcholine is involved in low-frequency sleep-wake cycles of alertness, in addition to a rapid modulation of cortical processes involved in attention. The cholinergic BF is impacted early in the progression of Alzheimer's disease. However, age-related differences in the relationships between BF structure, functional connectivity, and attention are poorly understood. Neuropsychological assessment of cognition, anatomical and resting-state multi-echo functional MRI were analyzed in a sample of 145 younger (mean age=22y, SD=3y) and 75 older (mean age=68y, SD=6y), cognitively intact, healthy adults. In older adults, BF volume was smaller than younger adults (p<.01) and was related to a measure of executive attention (self-ordered search), where larger BF volume was associated with faster reaction time (r =-.24, p<.01) and higher task accuracy (r =.23, p<.05), after accounting for sex, age, education, and intracranial volume. No associations were observed for episodic memory, vocabulary or processing speed (p's>.20). Age-group differences were also observed in a multivariate partial least squares analysis comparing BF connectivity with known cortico-cortical resting state networks (p<.001). In young adults, the magnitude of BF connectivity was higher in regions of the limbic, salience, and somatomotor networks. In contrast, older adults showed greater BF connectivity to regions of the default network. These results provide novel evidence that functional connectivity between the BF and neocortex changes with advancing age, and that these functional changes are related to BF structural integrity and executive attention.

TALK 7: Experience sampling during fMRI reveals distinct dynamics in the stream of thought

Sneha Sheth, University of British Columbia

One of the most striking features of human consciousness is its ability to foster an ongoing and seemingly continuous stream of thought. How do mental states unfold over time as the mind moves from one thought to another? The Dynamics of Thought framework has suggested a taxonomy of thought based entirely on the way it moves over time (i.e. strength and type of constraints applied on thought) rather than features of its content (e.g., task-relatedness). We empirically tested two kinds of dynamics proposed in this framework: deliberately constrained and relatively unconstrained (i.e. spontaneous) thought. Our study attempted to characterize the brain regions and networks involved in these phenomenally distinct transitions between mental states. In our experience sampling paradigm, participants were asked to let their thoughts unfold naturally as they were intermittently probed to rate their thoughts on the degree of free-movement and active-direction while in an fMRI scanner. Results show that regions of the medial-temporal subcomponent of the default-mode network, specifically, the hippocampus and parahippocampus, were more engaged during relatively unconstrained thought. Regions of the Fronto-Parietal Control Network were more associated with constrained thought. Our findings suggest that executive regions are more associated with strong constraints on the stream of thought whereas default network regions, specifically the medial temporal subcomponent, are more active when constraints on the stream of thought are relatively weak. Our study also validates the effectiveness of a combined approach of experience sampling and fMRI in the context of subtle thought dynamics.

TALK 8: Healthy aging impacts the construction but not the elaboration of social prospective thoughts

Gaelle Doucet, Boys Town National Research Hospital

The default-mode network (DMN) supports imagining episodic future scenarios and its regional constitution changes over the lifespan. The aim of this study was to investigate the DMN during the generation of social prospective thoughts using functional MRI (fMRI) from adolescence to late adulthood. Further, we tested whether different life stages (i.e., adolescence, early adulthood, late adulthood) were associated with differences in the DMN activation while constructing and elaborating prospective thoughts. To do so, we recruited a total of 146 healthy participants (27 adolescents: mean(sd) age=14.86(2.07) years, 14 males; 79 young adults: age=24.26(3.44) years, 33 males; 40 older adults: age=62.20(6.31) years, 16 males). The social prospection fMRI task consisted of two runs composed of 27 pseudo-random scenarios, each. Scenarios shown were positive or negative social events, or a control (non-social) scenario to imagine. Participants were instructed to press a button immediately after constructing the scenario and elaborate for the remaining time (total: 11sec). There was no significant difference in reaction times to construct events between groups. As expected, the fMRI results showed activation in the DMN during social scenarios, compared to control scenarios, across all participants. However, older adults showed an overall reduction of activation in the whole DMN while constructing social scenarios relative to young adults. No other age differences were revealed, including during the elaboration phase. The present findings provide evidence that healthy aging impacts social future thinking, particularly the construction phase, and may help identify biological factors that influence the generation of social prospective thoughts.

TALK 9: Human Brain Constructs Cognitive Maps Adaptively by Re-Scaling Abstract Concepts

Hai-Tao Wu, Peking University

It has been proposed that the brain organizes concepts as different axes into multidimensional spaces where items are embedded. Gridlike patterns associated with concept representation have been observed in the human medial prefrontal cortex (mPFC) and entorhinal cortex, suggesting a spatial coordinate system similar to those coding psychical environments. However, different from mapping physical spaces, whose metrics are naturally consistent between dimensions, constructing multidimensional concept spaces involves determining the metric relationship between distinct, sometimes incomparable, concepts. For example, when a cognitive map constitutes fruit diameters and tartness as two dimensions, which scales should be used for representing these disparate concepts, respectively? Here, we propose that the brain represents conceptual cognitive map with adaptive scales, adjusting for the statistical distribution of item features in the environment and maximizing representation precision with limited coding capacity. To test this hypothesis, we created two 2D conceptual spaces with different measurement ranges of item features. Two groups of subjects were trained to learn one of two conceptual spaces. Using fMRI, we show that the mPFC in both groups demonstrated the well-established effect of 6-fold modulation when subjects mentally navigate in different directions as defined by the hypothesized adaptive scales. Importantly, comparing with a range of alternative representational scales, the effect was most prominent when tested using the putative adaptive scales. These results point to an organization principle for flexible, context-dependent construction of abstract cognitive maps.

TALK 10: Neural mechanisms of cognitive effort-based decision-making: a multimethod approach

Jennifer Crawford, Washington University

Many daily-life activities require cognitive effort, yet individuals differ in their willingness to engage in those that are cognitively effortful. Individual differences in the subjective value (SV) associated with cognitive effort have been linked to both striatal dopamine D2 receptors (D2R) and to cortical regions supporting cognitive control (e.g., dorsal anterior cingulate cortex; dACC). To date, however, no studies have acquired within-person data on both dopamine-receptor density and brain activity dynamics during cognitive effort decision-making, nor linked these types of data to effort-based decision-making in daily life contexts. Here, we employed simultaneous PET-fMRI scanning, combined with ecological momentary assessment (EMA), to examine whether individual differences in brain activity and D2R density related to cognitive effort decision-making in both neuroeconomic task performance and daily life activities. Brain activity was monitored with fMRI while participants (N=26) completed the Cognitive Effort Discounting paradigm (Cog-ED) across two distinct cognitive domains (working memory, speech comprehension), while D2R binding was measured with the high-affinity, high-specificity PET radioligand [11-C]NMB. Participants also completed a 7-day EMA measuring the mental demands of daily activities. Across both domains, dACC activity tracked the relative SV of high vs. low-effort options, and participants' behavioral (choice) sensitivity to this relationship. Furthermore, individual differences in caudate D2R density were related to both fMRI activity modulation (reflecting the encoding of cognitive effort SV) and to daily-life engagement in mentally demanding activities. Together, these findings highlight the utility of multimethod experimental approaches to understand individual differences in complex behaviors such as decision-making based on cognitive effort.

TALK 11: Spatial scales of coding for working memory in primate lateral prefrontal cortex

Jacob Miller, Yale University

The prefrontal cortex (PFC) is consistently active during working memory (WM). While non-human primate (NHP) electrophysiology finds that PFC maintains WM representations, these item-related PFC signals are harder to detect with human neuroimaging. This discrepancy may result from spatial intermixing of neurons in PFC with different functional tuning. However, uncovering the functional microcircuitry for WM is difficult without detailed spatial organization about neuronal populations. Here, we leveraged a novel, two-photon calcium imaging dataset in NHPs (Xie et al., Science, 2022) to investigate the functional organization of WM circuits. In a multi-item delayed saccade task, 2 or 3 spatial locations were sequentially presented and subjects had to reproduce the target locations, in order, after a WM delay period. During task sessions, calcium traces were recorded from 20 fields-of-view (500x500um) in area 9/46 of lateral PFC (~3,600 total cells). We then analyzed the relationship between WM coding and microscale organization. Neurons with the strongest conjunctive/abstract coding - whose spatial tuning changed based on the sequence position in WM - were clustered tightly together at a 100um scale. This single-neuron organization also influenced population decoding measures: neural activity spatially averaged at finer scales (25um) showed stronger WM item representations at position 1 in sequences, but this spatial scale degraded at positions 2 and 3 with increased WM load. Overall, there is a fine microscale organization of abstract WM coding in PFC likely inaccessible to voxel-level sampling, helping to reconcile discrepancies between human neuroimaging and NHP electrophysiology perspectives of WM coding in PFC.

TALK 12: A single cell correlate of theta-gamma phase amplitude coupling during working memory in the human hippocampus

Jonathan Daume, Cedars-Sinai Medical Center

Phase amplitude coupling (PAC) is thought to be crucially involved in interactions between cognitive control and stimulus processing during working memory (WM) maintenance. However, it remains unknown how PAC relates to spiking activity of single cells. Here, we recorded single cells and local field potentials from the human brain while patients performed a WM task (44 sessions, 36 patients, 1518 neurons). We observed strong theta-gamma PAC in the medial temporal lobe during the WM delay period. Only in the hippocampus, however, PAC differed as a function of load with stronger PAC observed in load 1 as compared to load 3. Weak to no PAC was observed in the medial frontal lobe. We identified neurons in the hippocampus whose firing rate specifically followed local theta-gamma PAC during the WM delay period. These PAC cells differed from category cells whose firing rate was indicative of stimulus identity and showed stronger spike-field coherence to gamma when their preferred category was held in mind. PAC cells, on the other hand, showed stronger phase coupling to frontal theta oscillations with higher WM loads, indicating their involvement in cognitive control rather than stimulus maintenance. Structured noise correlations between PAC and category cells moreover allowed for efficient representations of stimulus identity in the hippocampus. Our results provide in-depth insights into the single cell correlates of interactions between frontal cognitive control as well as posterior sensory processing and suggest a functional role of PAC cells in enhancing the ability of briefly maintaining sensory information in mind.

TALK 13: Working memory is composed of distinct subcomponents

Gayathri Satheesh, New York University Abu Dhabi

Is working memory (WM) a unitary construct, or is it composed of distinct functions? In line with this latter view, focal lesions typically do not result in an overall loss of WM function but instead elicit unique patterns of nuanced behavioral deficits. To directly address this question, we designed a novel visual WM battery to selectively engage putative WM subcomponents: storage, selection, resistance, updating, and manipulation. On each trial, participants maintained the colors and locations of multiple discs over a brief memory delay and reported the location of the cued disc. We varied demands on individual subcomponents across trials by varying the number of discs to remember, the presence of irrelevant information during encoding or maintenance, or requiring subjects to reformat or manipulate memory contents. To test the independence of putative WM subcomponents, we conducted an online behavioral study where 200 participants were tested at two timepoints, T1 and T2, approximately 10 days apart. Individual subcomponent scores were calculated from subjects' behavioral error. The correlation between scores at T1 and T2 was significantly greater within- relative to between-subcomponents, arguing against a unitary WM construct. Instead, our data was best described by a model that included at least four subcomponents. In a second experiment, we collected fMRI data as subjects performed the WM battery. Representational similarity analysis revealed separable BOLD activation patterns for different subcomponents across frontal and parietal regions of interest. Taken together, these findings suggest that WM involves selective engagement of multiple subcomponents with distinct patterns of neural activation.

TALK 14: Rhythmic oscillations between task sets delineate stable versus flexible cognitive control

Thomas Biba, University of Toronto

The ability to multitask underpins cognitive control, yet how we flexibly switch between task sets remains unknown. One challenge is characterizing how cognitive stability, the propensity to efficiently perform a task amidst distraction, trades off with cognitive flexibility. Attention research provides a clue; people rhythmically alternate between sampling cued and un-cued spatial locations in phase with theta oscillations in frontoparietal networks. Here we adapted the behavioral oscillation approach to assess if people likewise rhythmically prepare for different tasks. In our task switching paradigm, participants perform one of two object classification judgments (size or indoor/outdoor) depending on the color of the preceding cue, meant to reset putative neural oscillations. Critically, we systematically varied the cue-to-object stimulus onset asynchrony (SOA; 200-1100ms; 28 increments of 33ms) to reconstruct a time-course of how classification performance varied during the milliseconds following the cue (N=120). Analyses revealed theta oscillations in reaction time on both tasks (in/out: 5-8Hz, p<0.05; size: 5-6Hz, p<0.001). Remarkably, theta phases were roughly 180 degrees offset between the two tasks (Mc=-174.8, rho=0.25, p<0.001), as though people alternated between preparing for each task several times per second. Furthermore, the degree of phase offset between task rhythms had telling links to performance: participants with a greater phase difference between tasks (i.e. approaching 180 degrees) were faster at classifying objects in general (R2=0.06, p<0.001), but showed larger switch costs (R2=0.17, p<0.001). Our results suggest that trade-offs between cognitive stability and flexibility are respectively enabled by greater or lesser differentiation of task sets across hundreds of milliseconds.

TALK 15: Alpha desynchronization tracks the spread of attention across visual objects

Damiano Grignolio, University of Birmingham

Attention is sensitive to the boundaries of visual objects, such that selection of one part of a stimulus leads to the prioritization of other parts of that same object. This has been interpreted as reflecting a low-level perceptual mechanism supporting segmentation, which engenders the automatic 'spreading' of attention within objects. We used human electrophysiology to test these ideas during preparatory attention. In our paradigm, participants were auditorily cued to attend to one of 4 spatial positions located at the ends of two rectangles. Prior work has demonstrated that participants are faster to respond to a target that subsequently appears at the cued location, but that there is also a benefit when the target appears at any other location on the cued object. In our task, the rectangles were either oriented vertically, such that they were each presented in one hemifield, or horizontally, such that each subtended the vertical meridian of the display. We collected EEG data and quantified oscillatory alpha (8-12 Hz) power. We observed the well-known effect that alpha contralateral to the cued location decreased in amplitude, reflecting the deployment of attention to the cued visual hemifield. Critically, this effect was reduced when the rectangles were oriented horizontally versus vertically. We interpret this as evidence that attention-related alpha lateralization is reduced when attention spreads across objects in one visual hemifield, versus when attention spreads across visual hemifields. These results are consistent with the idea that object attention involves changes in the allocation of preparatory visual spatial attention.

 

Data Blitz Session 2

Saturday, March 15, 12:00 – 1:30 pm, Grand Ballroom B/C

Chair: TBA

Speakers: Elizabeth Toomarian, Anna Borne, Megan Hillis, Sophie Jano, Lorna Quandt, Maya Yablonski, Holly Zaharchuk, Joseph Salvo, Victoria Hossack, Maggie Baird, Lukasz Bola, Danlei Chen, Alexis Kidder, Athena Willis, Yuan Tao

 

TALK 1: Two weeks of classroom-based training changes neural responses for lexical access: insights into naturalistic education by bringing SSVEP and EEG into schools

Elizabeth Toomarian, Stanford University, Synapse School

Segregating the lexical processes underpinning word recognition, especially in early readers, has been challenging in previous literature employing Steady-State Visual Evoked Potential (SSVEP) paradigms. Recently, our group (Wang et al. 2022) found robust lexical responses in early readers by slowing down SSVEP presentation rates, and using high frequency words. The current study extends this approach to measure whether short-term training would affect the circuits of lexical access beyond low-level visual processing. Three lists of five-letter low frequency (<1 per million) words were prepared, with 20 items for each list. Unigram, bigram, trigram frequencies, number of phonemes and syllables, and orthographic structures were well matched across these three-word lists. These lists were semi-randomly assigned across three classes of early readers ranging from age 6-8 years. After training on the assigned word list, EEG data were recorded while participants (n=28) were presented with trained (from their own class) and untrained (from other classes) five-letter words, at 1/3Hz (i.e., one trained and two untrained words per second) frequencies. Contrasts of high frequency words (> 500/million) vs. pseudowords and medium frequency words (100~500/million) vs. pseudowords were also used to test whether the training effect of low frequency words reached the level of lexical processing. Trained five-letter words evoked neural activations over the occipito-temporal region, similar to the activation area evoked by high frequency words. This finding suggests that neural markers for word lexical access develop rapidly after a short term of formal training in school.

TALK 2: Evaluation of inter-cognitive interaction in healthy subjects and perspectives in Rasmussen encephalitis after hemispherotomy: a behavioral network approach

Anna Borne, Univ. Grenoble Alpes, CNRS, LPNC

Traditionally, cognitive functions (i.e., language, memory, executive functions, social cognition) are considered distinct in terms of involved mechanisms and brain representations. However, current research tends to consider cognitive domains as intertwined, working in interaction in larger neurocognitive networks. In the present study, we aim to characterize such inter-cognitive functioning via behavioral measures for different cognitive domains, adopting a network perspective based on graph theory (GT). For this purpose, 165 healthy young adults (97 female) completed a battery of behavioral tasks (LEXTOMM; Language, Executive Functions, Theory of Mind, Memory). A cross-correlation matrix between each task performance (%CR, RT ms) was computed to assess inter-cognitive influences. Network analyses were then proposed to investigate this cognitive landscape from an integrative perspective. Correlations between tasks emphasize the interplay between language, memory, and executive abilities in healthy functioning. Furthermore, GT metrics highlighted a structured cognitive network (global efficiency = 0.13; clustering coefficient = 0.06), with the semantics being the major hub, followed by syntax, memory, and inhibition. As a preliminary work, we also applied GT analyses to a clinical population including 12 adult patients who underwent hemispherotomy in childhood to treat Rasmussen's encephalitis. Results suggest a less structured cognitive network (global efficiency = 0.16; clustering coefficient = 0.14) with hub displacement in patients (i.e., flexibility, semantic, phonology, and visuo-perceptive tasks revealing as major hubs) suggesting significant cognitive restructuration associated with brain reorganization. Focusing both on healthy subjects and on clinical populations, GT approaches offer interesting perspectives for the comprehension of cognitive network organization and reorganization.

TALK 3: Decoding knowledge of newly-learned language from neural representations of semantic meaning

Megan Hillis, Dartmouth College

How is learning new information reflected in the brain? The acquisition of knowledge over the course of learning is often measured through behavioral tests, (e.g., pencil-and-paper tests), however, prior work has demonstrated that data-driven neuroimaging methods can pick up on meaningful changes in neural representations that reflect learning in a number of conceptual domains, including physics and engineering, computer science, and foreign language. Across two studies, we examine the use of these methods for decoding newly-learned information in this case focusing on hearing English speakers learning American Sign Language (ASL). In the first study, novice participants underwent very brief training (three 30-minute lessons) to learn a set of nouns in ASL, then completed a semantic task during fMRI scanning where the stimuli were presented in the newly-learned language (ASL), a well-known language (English), and an unstudied language (Russian). Using multivariate pattern analysis methods including representational similarity analysis (RSA) and decoding techniques, we found evidence at the group level of neural patterns related to semantic categorization when stimuli were presented in ASL and English, but not in the unstudied language (Russian). Then, in a follow-up study, we investigate the ability of data-driven neural scores derived from a similar analysis to predict behavioral scores at the individual level. Our results provide evidence for the ability of multivariate neuroimaging analysis approaches to detect shifts in understanding even in the earliest stages of language learning.

TALK 4: Expecting the unexpected: A reanalysis of a multi-laboratory study with an investigation of prior word surprisal

Sophie Jano, University of South Australia

Recent accounts suggest that the perceptual processing of language is facilitated by the prediction of upcoming information. However, how predictions are represented in the brain, and the extent to which prediction underlies linguistic processing, is unclear. The present study sought to examine the neural activity relating to prediction during sentence comprehension, via a reanalysis of Nieuwland and colleagues' (2018) replication of DeLong et al. (2005). Participants (n = 356) were presented with article/noun sentence continuations that varied according to word predictability whilst their electroencephalogram (EEG) was recorded. The present reanalysis measured frontal event-related potentials preceding the critical words, post-word N400 patterns, and inter-individual differences in intrinsic neural activity. Lexical surprisal was calculated as a measure of word predictability using Generative Pre-trained Transformer-2 (GPT-2). Linear mixed-effects regressions revealed larger N400 amplitudes to surprising nouns for those with low individual alpha frequencies (IAFs), suggesting that such individuals may be more inclined to update their predictive models as compared to high IAF individuals. Exploratory analyses supported DeLong et al.'s (2005) findings, revealing greater N400 amplitudes to articles with high versus low surprisal. This relationship was weakened when the surprisal of the two prior words increased, suggesting that repeated exposure to surprising information may prompt the brain to 'expect the unexpected.' These findings have important implications for existing neurocognitive models of language, by suggesting that prediction should not be studied in isolation. Rather, individual neural factors and the accumulation of predictability over time should be accounted for.

TALK 5: Deafness and ASL Fluency Each Differentially Impact Biological Motion Perception

Lorna Quandt, Gallaudet University

Some evidence suggests that native American Sign Language (ASL) users show faster and less effortful biological motion perception than hearing non-signers. This finding may be due to deaf signers' expertise in extracting relevant information from complex human movements. However, we do not yet understand if this advantage is due to signed language experience or the experience of being deaf. We created point-light display (PLD) motion stimuli and designed three tasks. The Random Dot Motion task presents random moving dots, and the participants judge whether more dots are moving left or right. Person Perception shows biological human PLDs and scrambled PLDs, and participants determine if a person is present. Action Identification shows biological human PLDs, both right-side-up and inverted, and asks participants to determine whether the action involves using a ball. We gathered accuracy and reaction time from 230 respondents with varying ASL fluencies (non-signers to fluent signers) and hearing statuses (n = 80 Deaf; 21 Hard-of-hearing; 130 Hearing). Participants performed the three tasks during an online experiment. We analyzed data using bivariate analyses and linear mixed models. We found that Deaf respondents performed significantly more accurately than the other groups on the Action Identification task. We also found that while holding Hearing Status constant, higher ASL Fluency led to a faster and more accurate performance on Action Identification. We found other significant effects of Hearing Status, Age, Age of ASL Acquisition, and ASL Fluency which will be discussed further. These data demonstrate the combinatorial effects of sign language use and

TALK 6: Subregions of the visual word form area show distinct patterns of functional connectivity

Maya Yablonski, Stanford University

The visual word form area (VWFA) is a region of left ventral occipitotemporal cortex (VOTC) which selectively responds to text. Recent findings suggest that the VWFA comprises at least two distinct subregions: the more posterior VWFA-1 is sensitive to visual features, while the more anterior VWFA-2 processes higher level language information. Complementary evidence suggests that these subregions also differ in their structural white matter connections. Here, we explore whether these two subregions exhibit different patterns of functional connectivity, and whether these patterns have relevance for reading development. We address these questions using two complementary datasets: Using the Natural Scenes Datasets (NSD; Allen et al, 2022) we identify word-selective responses in high-quality adult data, and investigate functional connectivity patterns of VWFA-1 and VWFA-2 defined at the individual level. We then turn to the Healthy Brain Network (HBN; Alexander et al., 2017) database to assess whether these patterns replicate in a large developmental sample (N=224, age range 5-21y), and to what extent they relate to reading development. In both datasets, we find that VWFA-1 is strongly correlated with bilateral visual regions including VOTC and posterior parietal cortex. In contrast, VWFA-2 is functionally connected to language regions in the frontal and lateral parietal lobes, particularly bilateral inferior frontal gyrus (IFG). Further, the connectivity strength between VWFA-1 and frontal language regions increases with age, while no correlations were observed with reading ability. Together our findings support the distinction between subregions of the VWFA, showing that adjacent regions are coupled with distinct brain networks.

TALK 7: Tracking the time-course of cross-dialect comprehension with ERPs: Comparing Southern and Mainstream US-accented speech perception

Holly Zaharchuk, The Pennsylvania State University

Listeners use social context to adapt to variation in speech. Despite this adaptability in speech perception, research with mono-dialectal speakers of Mainstream US English (MUSE) has demonstrated a consistent advantage for within-dialect (D1-D1) communication over cross-dialect (D1-D2) communication in terms of accuracy, speed, and cognitive effort. However, since bi-dialectal speakers with substantial exposure to more than one dialect are understudied. it is unclear whether the within-dialect advantage is due to production experience, comprehension experience, perceptions of prestige, or a combination of these factors. To investigate the mechanisms that underlie bi-dialectal speech perception, we are conducting a series of auditory EEG/ERP experiments with mono-dialectal MUSE participants and bi-dialectal Southern US English (SUSE) participants that differ in the predictability of the upcoming accent. In the first experiment presented here, we established an unpredictable dialect context by presenting auditory stimuli in MUSE and SUSE accents in random order. Mono-dialectal MUSE participants performed a cover task while they listened to real words and pseudowords in both accents. Results indicate that phonetic and lexico-semantic access are disrupted in D1-D2 communication. Between 150-300ms, MUSE real words elicited larger P200 effects than SUSE real words, reflecting less effortful phonetic access for the D1 accent. Between 300-500ms, SUSE tokens elicited stronger N400 effects than MUSE tokens, reflecting more effortful lexico-semantic access for the D2 accent, regardless of word type. These findings contribute to the linguistic diversification of traditional speech perception models and set the stage for future experiments that manipulate socio-indexical factors and accent predictability.

TALK 8: The transmodal distributed language network includes an inferior temporal region that shows selectivity for visual word-forms

Joseph Salvo, Northwestern University

Modern estimates of the language network include association regions beyond the classic perisylvian areas. The entire distributed network shows responses to spoken or written language, and is identifiable using functional connectivity (FC) within individuals. The network often includes an underemphasized basal region half-way down the posterior-anterior axis of the inferior temporal cortex (ITC). This region is intriguing due to its anatomical proximity to the visual word-form areas (VWFA), which show selectivity for visual stimuli resembling written words. We investigated the relationship between this basal language network area and the VWFA. We recruited 8 healthy adults fluent in English for 8 MRI sessions. Multi-echo 3T functional MRI data were collected to improve signal-to-noise in the ITC. Tasks included an auditory language localizer, a visual category localizer, and a passive fixation task for network estimation. Data were processed using the 'iProc' pipeline, optimized for within-individual data alignment and minimizing smoothing, and were projected to the fsaverage6 surface. In each participant, seed-based FC, data-driven clustering, and a contrast from the auditory language localizer identified a shared set of distributed regions on the lateral surface. All participants demonstrated a language-active region halfway down the ITC's posterior-anterior axis. For all but one participant, this region overlapped with regions showing selectivity for letter strings without established meaning in English, in the visual category task. Neither face nor scene-selective regions overlapped consistently with the basal language region. Our results suggest that the hierarchy for recognizing visual word-forms converges with the transmodal distributed language network in the ITC.

TALK 9: Biophoton imaging predicts the severity of psychosis symptoms in healthy adult females and not males

Victoria Hossack, Laurentian University

Schizophrenia is a debilitating disorder which often results in irreversible tissue loss in the brain, making it a difficult disorder to treat. The defining feature of schizophrenia is psychosis, which also occurs in substance use disorders and mood disorders. A new line of research seeks to predict individuals who are at a risk of developing psychosis. Research in this area has included disciplines such as psychology, biology, and neuroscience. In this study we sought to investigate the relationship between psychosis symptoms and a novel variable, biophotons. Biophotons are particles of light from biological organisms and have never been included in the study of psychosis before. Previous studies have demonstrated that biophotons measured from human hands display differences when individuals are infected with a cold virus, have multiple sclerosis, or hemiparesis. We measured symptoms of psychosis in healthy adults with the Millon Clinical Multiaxial Inventory (MCMI), by focusing our analysis on Schizoid personality, Schizotypal personality disorder, and Schizophrenia spectrum disorder. In addition to measuring biophotons from the hands of participants, we also took electrocardiography (ECG) and quantitative electroencephalography (QEEG) measurements. There were consistent correlations of weak to moderate strength (Spearman rho ranged from 0.3 to 0.6) between biophoton measurements and Schizoid personality, Schizotypal personality disorder, and Schizophrenia spectrum disorder, however these results in only found in female participants (N=28), and not male participants (N=24). These results demonstrate the potential of biophotons to be a novel biomarker for mental health disorders.

TALK 10: Individual differences in multisensory illusory perception

Maggie Baird, Occidental College

We examined individual differences across two auditory-visual illusions: the McGurk Effect and the Sound-Induced Flash Illusion (SIFI). In the McGurk effect, visual information changes what participants hear; when the sound signal 'ba' is paired with a face mouthing 'va', participants often report hearing a fused sound like 'tha'. For the SIFI, sound changes visual perception; when a single visual flash is accompanied by two beeps presented in quick succession, many people report perceiving a second flash even though only one was presented. We were interested in the extent to which people experienced each of these illusions, whether their perceptual experiences were stable over time, and what brain states contribute to illusory perception. 49 undergraduate participants completed two experimental sessions while their brain activity was recorded using EEG; both sessions included a block of each illusion as well as several types of control trials. We found robust individual variability across both illusions such that some participants always, never, or sometimes experienced the illusions. Susceptibility was stable over time such that across both sessions, people remained either 'seers', 'non-seers', or 'sometimes-seers'. For the SIFI specifically, prior trial type was predictive of whether they would experience the illusion. Moreover, we found neural differences in both central and occipital sites between 'seers' and 'non-seers'. We also report trial-by-trial based EEG analyses demonstrating differences between propensity to experience the two illusions. This study supports and extends the growing literature surrounding individual variability in perception of multisensory illusions.

TALK 11: Decoding spoken words in the early visual cortex of sighted and congenitally blind individuals

Lukasz Bola, Institute of Psychology, Polish Academy of Sciences

In blind individuals, listening to spoken words strongly activates the early 'visual' cortex. However, it is still unclear what properties of spoken words are captured by the early visual areas in the blind, and consequently, what are the implications of this finding for our theories of brain plasticity. To contribute to this debate, we investigated whether early visual cortex activation patterns in blind individuals represent differences between specific spoken words. Furthermore, we asked if some form of spoken word representation can be observed also in the early visual cortex of sighted individuals. We enrolled 20 sighted and 17 congenitally blind participants in an fMRI experiment, in which they listened to spoken words and made semantic decisions on word referents (animals and everyday objects). We used multi-voxel pattern analysis (MVPA) to reveal, in each participant group, brain regions representing differences between words presented during the study. We found that specific spoken words can be decoded from early visual cortex activation patterns in both blind and sighted participants. Furthermore, the searchlight analysis showed that brain networks representing differences between spoken words are overall very similar in both participant groups. We conclude that the overall topography of the spoken word processing networks, as investigated with MVPA, is relatively robust to changes in visual experience. We also suggest that visual cortex responses to spoken words, observed in blind individuals, might originate from neural representation that is computed in this region also in sighted individuals.

TALK 12: Prediction in the midbrain: layer-dependent pattern of human superior colliculus activity during decision-making predicts the modality of expected sensory stimulation

Danlei Chen, Northeastern University

The superior colliculus (SC) is a small structure in the vertebrate midbrain. Evidence from non-human vertebrates shows that the superficial and deep SC layers are involved in visual and somatosensory processing, respectively. Evidence from humans also showed visual and visuomotor processing in SC superficial layers. These studies, however, focused on SC in response to stimulation, rather than prediction. Using 7-Tesla ultra-high-field fMRI (1.1mm isotropic), we localized and measured the human SC BOLD signals during a decision-making task in which a selection between two visually presented shapes was followed by either a visual or somatosensory stimulation in two separate groups of participants (N=40 for each). Across 120 trials, participants actively selected between two shapes or passively viewed a selection made by the computer. The selection was then followed by a neutral or negative stimulation either in the visual domain for some participants (i.e., affective images) or in the somatosensory domain for others (i.e., pressure on the thumbnail). The entire human SC showed greater signals during both active and passive decisions compared to baseline, and greater SC signals in active compared to passive decisions. Critically, superficial SC layers showed greater signals when visual stimulation was expected during decision-making, while deep SC layers showed greater signals when somatosensory stimulation was expected. Thus, layer-dependent SC signals were predictive of the expected sensory stimulation in a manner that was consistent with the anatomical evidence of sensory specificity in SC layers. These results suggest that human SC might be important in the predictive processing during decision-making.

TALK 13: Evidence from prosopometamorphopsia and mouth-specific distortions for independent representations of individual facial features

Alexis Kidder, Dartmouth College; NIMH

Face perception research has largely emphasized holistic processing of faces, and work exploring whether and how individual facial features are represented has been limited. However, recent psychophysical, neuroimaging, and single-unit studies suggest individual facial features may be encoded independently (de Haas et al., 2016; Zhang et al., 2021; Waidmann et al., 2022). Here, we present evidence for mouth-specific representations in the human face processing system from a case study of Willie, a right-handed, 38-year-old man who experiences prosopometamorphopsia (PMO). Willie's day-to-day distortions occur exclusively to mouths, and include whole mouth duplications, illusory mouth motion, and changes to lip shape. We ran a battery of 41 tasks to characterize Willie's distortions. Of the evoked distortions, 98.7% of the distortions were to faces, and 86% of these distortions only affected mouths. We tested predictions of four alternative accounts of the process producing the distortions: (1) low-level visual processing, (2) general visual object processing, (3) the lower half of viewer-centered face representations, or (4) face-centered mouth-specific representations. To test accounts 1 and 2, Willie viewed 946 low-level simple shapes, common objects and scenes, and reported only 2 distortions evoked by objects. To evaluate accounts 3 and 4, faces were displayed at six different picture-plane orientations. Willie saw distortions to mouths rather than features in the lower half of the face at each orientation. Taken together, these results indicate that Willie's distortions reflect disruptions to feature-specific, face-centered representations. His case indicates that mouths, and other facial features, may be represented independently from each other.

TALK 14: Perception of Signing Avatars? Movement Leads to Predictive Processing and Non-Linear Model of Mu / Alpha Frequency Power Changes

Athena Willis, Gallaudet University

Recent research shows that deaf signers show increased behavioral and neural sensitivity to certain types of movement, such as biological motion, human actions, and signing avatars. However, other work suggests that in deaf signers exposed to signed language before age five, there is minimal involvement of the Mirror Mechanism during the perception of signed languages. The disparity in those findings is a crucial question because of the emergence of signing avatars designed to engage learners' prior embodied experience for learning. To understand the role of the mirror mechanism in the perception of signing avatars' movements, we created stimuli that vary in two ways. Four signers differ in their motion (Familiar or Unfamiliar signing movements) and form (Human or Avatar). We collected EEG oscillations from deaf signers (N = 21) as they watched the movements of individual signed words from four different signers. We conducted ANOVA planned contrasts and time frequency analysis between each signer. We found a significant increase in self-reported behavioral rating of Familiarity with the Familiar Avatar after the EEG experiment. While participants were observing a still Familiar Avatar, we found a significant synchronization in mu frequency compared to other three signers. During the perception of signers' movement, we found a pattern of significant power changes in mu frequency across signers that suggests a non-linear model of sensorimotor processing. Our pre-registered EEG study suggest that during the perception of signed words, deaf signers engage their mirror mechanism for predictive processing and action simulation of human movements.

TALK 15: Cortical and subcortical mechanisms of orthographic learning

Yuan Tao, Johns Hopkins University

Research on orthographic learning (in reading and dyslexia) has focused largely on cortical mechanisms. However, it is well-understood that verbal learning recruits both subcortical (e.g., hippocampus) and cortical mechanisms. As highlighted in the Complementary Learning Systems framework (McClelland, et al., 1995), these regions instantiate different types of learning mechanisms whose involvement varies over the time-course of learning. To examine orthographic learning in real time, we adapted the Law et al. (2005) associative learning paradigm requiring participants to learn, through trial and error, the relationship between the pronunciations and spellings of pseudo-words during fMRI scanning. Thirteen healthy volunteers learned the pseudo-words in two twenty-minute scanning sessions, with evaluations of in-scanner and post-scan accuracy. We examined BOLD response for learning trials of different levels of memory strength (Smith et al., 2004) in the hippocampus and the left ventral occipital cortex (LVOT; associated with orthographic processing). We found: (1) Both left and right hippocampi showed that activation increased with memory strength (LH: p=0.0021, RH: p=0.0002), whereas the LVOT showed decreased activation (p=0.03); (2) Larger hippocampal BOLD changes were associated with smaller LVOT changes (r=0.68, p=0.004); (3) Higher post-scan accuracy was correlated with greater activation changes of the hippocampi (r=0.61, p=0.01), but not the LVOT (r=0.38, p=0.11). The results reveal two distinct neural mechanisms in the initial orthographic learning stages assessed in this study. Generally consistent with the CLS framework, the hippocampus specifically contributes to better learning outcomes, while decreased activation of the cortical orthographic processing regions may reflect BOLD-adaption/familiarization.

 

Data Blitz Session 3

Saturday, March 25, 12:00 – 1:30 pm, Bayview Room

Chair: TBA

Speakers: Danika Geisler, Jingyi Wang, Siddhant Iyer, Courtney Jimenez, John Thorp, Shenyang Huang, Stephanie Simpson, Ian Ballard, Nick Wellman, Jia-Hou Poh, Monica Thieu, Victoria Schelkun, Alyssa Sinclair, Wen Jian, Dylan Curtin

 

TALK 1: Self-focused by default: Spontaneous medial prefrontal cortex and DMN core subsystem activity during rest predicts the desire to think about the self

Danika Geisler, Dartmouth

People are particularly self-focused. Yet, the basic brain mechanisms that bias us towards self-focus remain unclear. In the main task of our fMRI session, each trial started with a pre-trial jittered rest, then the trial in which subjects chose who (themselves, a designated friend, or Biden) they wanted to think about in a later task. Parametric modulation analysis of the pre-trial jitter activation with response time to the next trial as the parametric modulator revealed the MPFC during pretrial rest more strongly predicted self (vs friend and Biden) decisions. In other words, stronger 'default' MPFC activation during brief rest biases self-focus on a moment-by-moment basis. Additionally, multi-voxel pattern analysis (MVPA) revealed that spatial patterns in the MPFC during pre-trial rest predict the subsequent choice to think about the self (vs. others) on the next trial. We additionally found that the DMN core is able to predict the subsequent choice to focus on the self (vs. others) more accurately than a) other DMN subsystems and b) the whole brain. Finally, we applied the DMN core MVPA pattern to each TR of a resting state scan that occurred prior to the experimental tasks. During this rest scan, participants periodically rated the extent to which they were thinking about themselves. Participants with DMN core patterns during rest that were highly similar to the pre-trial MVPA pattern reported being the most self-focused during their rest scan. The current results suggest that 'defaulting back' to the MPFC and DMN core subsystem nudges us toward self-focus.

TALK 2: Time and emotion modulate the intrinsic functional organization of lateral prefrontal cortex

Jingyi Wang, University of California, Santa Barbara

Control signals in lateral prefrontal cortex (LPFC) are thought to be organized along a rostro-caudal axis of temporal abstraction, with rostral LPFC (frontopolar cortex/FP) supporting abstract and temporal context-dependent forms of cognitive control (Badre and D'Esposito, 2007; Badre and Nee, 2018). Prior work suggests that the similarity structure of intervoxel functional connectivity patterns in LPFC reflects its intrinsic functional organization, which constrains abstract, goal-directed cognition (Waskom et al., 2017). Here, we used dense sampling fMRI to examine whether the intrinsic functional architecture of LPFC differentially reflects changes in temporal context along the rostro-caudal axis. We also examined whether mood changes differentially explained LPFC functional connectivity patterns given evidence that emotional valence encoding in FP modulates goal-directed cognition (Lapate et al. 2022). Two participants (n=1 Female, 23-y-old; n=1 Male, 26-y-old) underwent daily resting-state scans for n=30 consecutive days. We correlated changes in the similarity of intra-regional functional connectivity patterns in LPFC with changes in elapsed time. We found that the similarity of functional connectivity patterns in FP tracked (and correlated negatively with) elapsed time elapsed over a 30-day period-an association that was attenuated in mid-LPFC, and absent in caudal PFC regions. Moreover, emotional-state changes differentially explained the similarity structure of functional connectivity patterns in LPFC, with the strongest association found in FP, which progressively attenuated in caudal regions. Collectively, these results indicate that time and emotion differentially modulate the intrinsic functional architecture along the rostro-caudal axis of LPFC.

TALK 3: Inter-subject variability in post-encoding default network connectivity explains affects of social memories

Siddhant Iyer, Dartmouth College

Often after interpersonal conversations, each of us recalls the experience differently; some fondly, some with disdain; some are inspired, some deflated. Previous studies have investigated the role of the brain's default mode network (DMN) in variable interpretations of similar social experiences (Finn et al., 2018), yet the network's role post-encoding has largely been overlooked. Given the importance of post-encoding DMN connectivity in social memory consolidation (Collier & Meyer, 2020), here we asked if people remember the same social experience fondly versus with disdain, in part, because of how their DMN consolidates the experience after encoding. To test this, subjects (N=40) underwent fMRI while completing a baseline rest scan, encoding videos of people sharing emotional information, and a post-encoding rest scan. Next, they freely recalled everything they remembered. We calculated inter-subject similarity in timecourse correlations between DMN regions in each experimental phase and sentiment analysis on recall data. Representational similarity analysis between a) subject-by-subject connectivity similarity during post-encoding rest and b) by-subject memory affect showed that subjects with negative memories exhibited similar DMN connectivity, while those with positive memories exhibited idiosyncratic DMN connectivity. Temporal analyses revealed this post-encoding effect occurs quickly, immediately after encoding. Importantly, we found no effect when analyzing video-watching or baseline rest, ruling out perceptual or trait-level resting state explanations. Connectivity outside the DMN yielded null results, further suggesting specificity to DMN. The findings suggest individual differences in DMN connectivity immediately after social encoding may explain why some recall the same social experience fondly while others with disdain.

TALK 4: Dorsomedial Prefrontal Cortex (DMPFC) Prioritizes Social Learning at Rest

Courtney Jimenez, Dartmouth College

As we move through everyday life, we come across an abundance of information. Yet, some experiences stick with us while others are forgotten. Is certain information from encoding prioritized in memory? If so, how? One possibility is that social information-that is, information about people-may be prioritized via consolidation mechanisms at rest. Here, we implement a multivariate neural pattern reinstatement analysis with naturalistic stimuli to show that the amount of social reinstatement in the DMPFC is significantly related to social memory performance. Additionally, we show that nonsocial reinstatement in the lVLPFC is significantly related to nonsocial memory performance. Critically, a linear mixed effects model reveals that the correlation between the number of DMPFC social pattern reinstatements and social memory performance is driven by early rest. We don't see evidence of the same temporal prioritization in the relationship between the number of lVLPFC nonsocial pattern reinstatements and nonsocial memory performance. Further, we replicate findings that implicate the hippocampus in a general consolidation function at rest. We find that the amount of correct pattern reinstatement in the right hippocampus at rest is negatively correlated with overall memory performance. Collectively, these results suggest that the link between neural pattern reinstatement during rest and subsequent memory may be supported by different prefrontal regions for social (DMPFC) and non-social (lVLPFC) memory. These results provide evidence that the DMPFC, a key region of the default network, prioritizes the consolidation of social information for memory during earlier moments of rest.

TALK 5: Hippocampo-cortical replay during rest shapes memory updating

John Thorp, Columbia University

Our understanding of when and how memories update is a burgeoning area of research. Prior work has shown that partial reminders open up a window in which memories can be modified. Recent neuroimaging work has provided evidence that hippocampal univariate activity after these reminders relates to the extent to which memories are updated. We were interested in whether and how partial reminders facilitate reconsolidation by examining neural processes associated with memory consolidation. To this end, we examined post-reminder memory replay during rest and assessed the number and systems-level coordination of replay events using fMRI. Replay was examined locally in the hippocampus as well as across different whole-brain networks. We found that the frequency of replay events for interrupted videos was generally significantly enhanced compared to uninterrupted, or full, videos across both the hippocampus and cortical networks. Similarly, we found that the proportion of simultaneous, coordinated replays between the hippocampus and cortical networks was generally greater for interrupted videos than full videos. Critically, the number and coordination of replay events in some of these areas protected against errors for interrupted videos but led to errors for full videos. Future analyses will explore and characterize the specific relationships between post-reminder memory replay and later memory distortions.

TALK 6: Hippocampal interactions with visual and semantic representations in the cortex support subsequent perceptual and conceptual memory

Shenyang Huang, Duke University

fMRI studies of episodic memory have found that subsequent memory is associated with increased univariate activation in the hippocampus and multivariate representation of visual and semantic stimulus features in cortical regions. Nonetheless, it remains unclear how hippocampal functions integrate with distinct cortical representations to facilitate successful encoding. We collected fMRI data while participants encoded images of real-world objects, and then tested their memory for object concepts and image exemplars (i.e., conceptual and perceptual memory). We quantified hippocampal engagement on each trial in four distinct ways: activation level (univariate activity), neural pattern similarity (correlation in activity patterns across objects), and representational strength (using representational similarity analysis, separately for visual and semantic features). While patterns of cortical visual and semantic representations replicated well-known cortical regions (e.g., visual: occipital cortex; semantic: angular gyrus), we found no evidence of visual or semantic representation in the hippocampus. Critically, hippocampal function modulated the impact of cortical representations on subsequent memory in a memory-specific manner, such that hippocampal modulation of visual (or semantic) representations boosted perceptual (or conceptual) memory in regions associated with visual (or semantic) processing. In predicting perceptual memory, hippocampal activity augmented the effects of visual representations in medio-ventral and lateral occipital regions. In predicting conceptual memory, hippocampal activity enhanced the effect of semantic representations in left inferior frontal gyrus and hippocampal semantic representation boosted the effect of semantic representations in angular gyrus. Collectively, these results suggest the particular contribution of hippocampal modulations on cortical representations specific to the type of information and memory demands.

TALK 7: Effects of aging, neurodegenerative disease, and MTL damage on autobiographical memory recall: A meta-analytic review of the Autobiographical Interview

Stephanie Simpson, University of Toronto; Rotman Research Institute at Baycrest

The Autobiographical Interview is a standardized method of assessing memory for real-life past experiences. It is widely used to derive separate measures of internal (episodic) and external (non-episodic) details from freely recalled autobiographical narratives. This study aims to synthesize the literature on the Autobiographical Interview across the spectrum of healthy aging and neuropathology-related cognitive decline. Focusing on 46 studies with 1821 participants, we conducted a meta-analysis to quantify the pattern of details generated during autobiographical memory recall from healthy younger and older adults as well as patients with mild cognitive impairment (MCI), Alzheimer's Disease (AD), and medial temporal lobe (MTL) lesions. Summary statistics for internal and external details along with inferential statistics concerning group differences were extracted from each article. We observed that the Autobiographical Interview is not only sensitive to the effects of normal aging, but also to cognitive decline associated with neurodegenerative disease and extensive MTL damage, with large effects on the generation of episodic details. These data demonstrate that: 1) fewer internal details were generated in aging and patients with suspected (MCI, AD) and confirmed (lesions) MTL-related neuropathology, 2) but only healthy older adults over-produced external details relative to controls. Results from this study extend the canonical episodic memory impairment observed in neurodegenerative disease and MTL lesions to naturalistic measures of memory that are more representative of real life. This work also sheds light on how mnemonic profiles of recovered episodic and non-episodic content can differentiate groups across the spectrum of age- and neuropathology-related impairment.

TALK 8: Striatal dopamine influences the hemodynamic response in humans

Ian Ballard, University of California, Berkeley

The cerebral vascular response has a critical role in satisfying neuronal demands and is the basis for BOLD imaging. Dopamine and vasculature are closely associated as dopaminergic neurons innervate microvessels and dopamine agonists can elicit cerebrovascular dilations (Edvisson et al., 1985; Krimer et al., 1998). In a group of 52 healthy male and female human subjects, we measured a proxy of hemodynamic delay using BOLD fMRI. We also measured dopamine synthesis capacity using the PET radioligand 6-[18F]fluoro-l-m-tyrosine ([18F]FMT). We found spatial differences of hemodynamic lags within the striatum. Hemodynamic responses in the nucleus accumbens, a major target of mesostriatal dopamine, peak an average of .5 seconds later than more dorsal regions of the striatum and much of cortex. Consistent with dopamine having a direct hemodynamic effect, we found a positive correlation between dopamine synthesis capacity as measured by PET and hemodynamic lag in the nucleus accumbens. In addition, in a separate cohort of 19 healthy male and female subjects performing a reward decision making task, we found that lags in the hemodynamic response are reduced by ~1s for positive relative to negative rewards, consistent with dopamine driving a faster hemodynamic response. In sum, we found convergent evidence that dopamine release in the nucleus accumbens leads to a faster hemodynamic response. Moreover, these results raise the possibility that hemodynamic lags in the nucleus accumbens may provide a proxy measure of dopaminergic tone in humans. However, the relationship between hemodynamic responses and dopamine in humans is unclear.

TALK 9: Brain white matter changes during a 1-year Antarctic winter-over mission

Nick Wellman, University of Pennsylvania

Long term spaceflight presents a unique set of stressors that are not well understood. Mitigating adverse effects of space exploration often focuses on the effects of microgravity exposure yet the impact of other variables, such as the isolated, confined, and extreme (ICE) environment created by space exploration, needs to be further explored. Here we measure changes in brain white matter using diffusion MRI in astronaut surrogates who wintered-over in Antarctica, an ICE environment. Crew members who wintered-over (n = 23) were compared to controls who did not (n = 15). Participants underwent MRI before (Pre), immediately after 12 months in the ICE environment (Post 1), and again 6 months later (Post2). Mixed-effects modeling was implemented using longitudinal ComBat to mitigate scanner site effects. Transient increases in axial diffusivity (AD) were found in crew members in the cingulum bundle (p = 0.008) and superior longitudinal fasciculi (p = 0.009) at Post1 that returned to baseline at Post2. Moreover, ICE-associated change in white matter was associated with cognitive performance, measures of activity, and sleep (Pearson r's > 0.50). Controls showed small, but typical age-related declines in fractional anisotropy in the corticospinal tract (p = 0.009), inferior frontal occipital fasciculi (p = 0.007), inferior longitudinal fasciculi (p = 0.02), and forceps minor (p = 0.03). The present data suggest ICE environments transiently alter brain white matter, which may have consequential effects on performance and behavior. Future studies elucidating brain changes after ICE exposure are needed given the interest in extended space explorations.

TALK 10: Lingering novelty signal facilitates the formation of enduring episodic memory

Jia-Hou Poh, Duke University

Detection of novelty has been proposed to initiate cascades of neuromodulatory activity beneficial for memory formation. Two key mechanisms proposed are cholinergic modulation of an 'encoding state' and dopaminergic tagging for the consolidation of lasting memories. While studies in humans have provided evidence of enhanced encoding following novelty detection, there is scarce evidence for memory persistence in humans. To examine if the persistence of memory is influenced by the detection of novelty in a preceding image, we analyzed data from the Natural Scenes Dataset. Participants (N = 8) performed multiple sessions of a continuous recognition task (Old/New judgment) where images were presented thrice with repetition intervals ranging from 0 to over 300 days. Analyses included only intervals where recognition accuracy was above chance. On initial presentation, participants were highly accurate in judging that an image is New, but they were also less likely to indicate so if it was preceded by a familiar image (p <.001), suggesting lingering mnemonic signals that influence the subjective experience of novelty. Retrieval was examined using recognition accuracy on the 1st repetition (i.e. 2nd presentation). Unsurprisingly, recognition decreased with longer intervals (p <.001). Crucially, images preceded by a Novel image during the first presentation showed a slower rate of decay compared to images preceded by an Old image (p <.001). These findings demonstrate that the lingering effects of novelty facilitate the formation of enduring memory. Ongoing fMRI analyses will examine how subjective novelty and memory persistence relate to the engagement of neuromodulatory networks during encoding.

TALK 11: Episodic-Semantic Linkage for $1000: Episodic memory bolsters acquisition of new semantic knowledge in trivia experts

Monica Thieu, Emory University

Some people exhibit impressive memory for a wide array of semantic knowledge. What makes these trivia experts better able to learn and retain novel facts? We investigated whether episodic memory can bolster learning of novel semantic information in trivia experts. We hypothesized that trivia expertise would be linked to stronger associative binding between complex semantic information and episodic features of an encoding event. 133 participants varying in trivia expertise completed a museum-themed memory task, in which they encoded two 'exhibits' of naturalistic facts paired with related photos. Afterward, participants were tested on cued recall of facts, forced-choice memory for photos, and forced-choice memory for each fact's encoding exhibit. As expected, greater trivia expertise was correlated with higher cued recall for novel facts. Among all participants, source memory for the museum exhibit predicted greater likelihood of fact recall. Conversely, photo memory dissociated trivia experts and non-experts: trivia experts were more likely to successfully recall a fact if they also correctly identified its associated photo, whereas fact recall and photo memory were unrelated among non-experts. These findings suggest that associative episodic memory might scaffold acquisition of new semantic memories in trivia experts They add to a burgeoning line of work highlighting shared cognitive and neural underpinnings of episodic and semantic memories. Finally, our work shows the value of studying trivia experts: a special population that can shed light on the mechanisms of memory.

TALK 12: Hippocampal and cortical activity mechanisms of episodic memory

Victoria Schelkun, Columbia University

Though our experiences unfold continuously, they are remembered as individual episodes. Prior work suggests that ongoing contextual stability supports temporal integration of sequential information, and that event boundaries disrupt ongoing integration thus leading to discrete episodes in memory. Event boundaries have been associated with robust effects on memory, yet it remains to be fully understood how the neural mechanisms at and around event boundaries support this process. In this study, we sought to characterize how activity patterns change in response to event boundaries, and how this subsequently affects memory. Participants underwent fMRI scanning while they viewed sequences of images that were organized into events defined by an associated auditory and motor context. Participants were later tested for item memory and temporal memory. We found that activity profiles in hippocampal and event-related cortical regions reflect the event structure, such that event boundaries are associated with a momentary shift in activation in these regions. Furthermore, trial-by-trial hippocampal activity is related to later memory strength and is moderated by associated cortical activity. We then computed levels of pattern separation in hippocampal subfields via measures of similarity between patterns of activity to test for differences in relational encoding representations as a function of the event structure. We find that the dentate gyrus engages in greater pattern separation within events than across events, suggesting a mechanism by which individual items become integrated into an episode in memory. These results shed new light on the dynamic hippocampal and cortical mechanisms by which event boundaries organize memory.

TALK 13: Instructed Motivational States Bias Reinforcement Learning and Memory Formation

Alyssa Sinclair, Duke University

Motivation influences goals, decisions, and memory formation. Imperative motivation links urgent goals to actions, narrowing the focus of attention and memory. Conversely, interrogative motivation integrates goals over time and space, supporting rich memory encoding for flexible future use. Here, we manipulated motivational states using cover stories presented before a reinforcement learning task: The Imperative group imagined executing a museum heist, whereas the Interrogative group imagined planning a future heist. Participants repeatedly chose among four doors, representing different rooms of the museum, to sample trial-unique paintings with variable rewards. The next day, participants in both groups performed a surprise next-day memory test. Crucially, only the cover stories differed between the Imperative and Interrogative groups; the reinforcement learning task was identical, and all participants only received payment after the memory test. In an initial sample and a pre-registered replication, we demonstrated that Imperative motivation increased exploitation during reinforcement learning. Conversely, Interrogative motivation increased directed (but not random) exploration. At test, the Interrogative group was more accurate at recognizing paintings and recalling associated values, relative to the Imperative group. In the Interrogative group, higher-value paintings were more likely to be remembered; Imperative motivation disrupted this effect of reward modulating memory. Overall, we demonstrate that a subtle motivational manipulation can bias learning and memory, bearing implications for education, behavior change, clinical interventions, and communication.

TALK 14: Dissociable Pupillary Response Patterns During Explicit and Implicit Memory Retrieval

Wen Jian, Brown University

The pupillary old/new effect refers to the larger pupil dilations elicited by previously studied items compared to new items during recognition memory retrieval; the effect is thought to reflect the strength of the memory trace such that more strongly encoded items elicit larger pupil dilations. In this study, we explore whether this interpretation generalizes to implicit as well as explicit memory retrieval conditions. For the explicit condition, 24 participants (age 18-28 years) rated the likability of concrete words during a study phase and provided an old/new response to words during the test phase. For the implicit condition, a separate group of 24 participants (age 18-28 years) received the same study procedure, but were administered a word-stem completion priming task during the test phase. Priming is reflected in the tendency to complete stems with previously studied words: If larger pupil dilation reflects greater memory strength, then successfully primed items should elicit greater dilation than unsuccessfully primed items. Pupillary data was recorded and analyzed using single-trial linear regression models. The expected pupillary old/new effect was observed in the explicit recognition memory task. However, the opposite pattern of pupillary response was observed in the implicit priming task, with successfully primed words eliciting a smaller pupil dilation than unsuccessfully primed words. These findings challenge the view that the magnitude of pupil dilation during memory retrieval directly reflects the strength of the underlying memory trace, but instead suggests that it reflects the interaction between memory strength and processes engaged under different memory retrieval conditions.

TALK 15: Dopamine D2 receptor blockade eliminates exercise-induced changes in cortical inhibition and excitation

Dylan Curtin, Monash University

There is compelling evidence from recent phase-II trials that cardiorespiratory exercise improves clinical outcomes in dopaminergic disorders. Animal models of Parkinson's disease highlight an increase in dopamine D2 receptor expression and enhanced synaptic plasticity as candidate mechanisms driving these benefits, but the link between the D2 receptor and exercise-induced synaptic plasticity in humans is unknown. Here, we examined the effect of a selective dopamine D2 receptor antagonist, sulpiride, on exercise-induced changes in synaptic plasticity. We acquired measures of synaptic excitatory and inhibitory activity of the primary motor cortex using transcranial magnetic stimulation (TMS), both before and after a 20-minute bout of high-intensity interval cycling exercise. We examined the effect of D2 receptor blockade (800 mg sulpiride) on these measures within a randomised, double-blind, placebo-controlled, crossover design. Sulpiride abolished exercise-induced modulation of the cortical excitation:inhibition balance relative to placebo (p < 0.001, Cohen's d = 1.76). Sulpiride blocked both the increase in excitation and reduction in inhibition that was observed following exercise in the placebo condition. Our results provide causal evidence that D2 receptor blockade eliminates exercise-induced synaptic plasticity, and have implications for how exercise should be prescribed in diseases of dopaminergic dysfunction, such as Parkinson's disease and schizophrenia.