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Mini-Symposium Sessions

Session #

Day

Date

Time

Location

Mini-Symposium Session 1

Sunday

March 29

10:00 am - Noon

Grand Ballroom A

Mini-Symposium Session 2

Sunday

March 29

10:00 am - Noon

Grand Ballroom B/C

Mini-Symposium Session 3

Sunday

March 29

10:00 am - Noon

Bay View Room

Mini-Symposium Session 4

Monday

March 30

10:00 am - Noon

Grand Ballroom A

Mini-Symposium Session 5

Monday

March 30

10:00 am - Noon

Grand Ballroom B/C

Mini-Symposium Session 6

Monday

March 30

10:00 am - Noon

Bay View Room

Mini-Symposium Session 7

Monday

March 30

3:30 - 5:30 pm

Grand Ballroom B/C

Mini-Symposium Session 8

Tuesday

March 31

10:00 am - Noon

Grand Ballroom A

Mini-Symposium Session 9

Tuesday

March 31

10:00 am - Noon

Grand Ballroom B/C

Mini-Symposium Session 1

Sunday, March 29, 10:00 am - Noon, Grand Ballroom A

What can be, or should be, the relationship between language and neuroscience?

Chair: Hanna Gauvin, Gent University
Speakers: David Poeppel, Sophie Scott, Fred Dick

The voluminous and fast-growing literature on language in the brain suggests that our understanding of how linguistic processes are computed by the brain is progressing by leaps and bounds. However, many if not most such studies come to the conclusion that ‘area x is involved in/responsible for linguistic process y’. This situation is hardly unique to the cognitive neuroscience of language, but clearly one we need to progress from. The aim of this mini-symposium is to stimulate debate - and potentially even generate some answers - about how we can leverage exciting new developments in natural language processing, linguistic typology, speech recognition, and other fields of linguistics to understand how our brain allows us to develop and master this most extraordinary, unique, yet ubiquitous human skill.

Talk 1: Correlational, integrated, and explanatory neuroscience of language

David Poeppel1,2; 1New York University, 2Max Planck Institute

What would an integrated approach to language research look like that connects theoretical, psycholinguistic, and neurobiological domains of inquiry? To what extent is ‘unification’ (e.g. in the sense of Marr) possible across domains? I discuss the outlines of a program of research at the center of which lies the idea that computational/representational (CR) theories of language must be used to investigate the neurobiological (NB) foundations of language. Unlike most approaches to the neuroscience of language - and borrowing from arguments advanced by Gallistel for the case of spatial navigation - I argue for a more ‘muscular’ cognitive science/linguistics that takes a leading role (in epistemological terms) in motivating neurobiological questions. Different ways are considered in which CR and NB might be connected. These are (1) a correlational way, in which NB computation is correlated with the CR theory (i.e. business as usual); (2) an integrated way, in which NB data provide crucial evidence for choosing among CR theories (this happens, but rarely…); and (3) an explanatory way, in which properties of the neurobiology explain in a causal, mechanistic sense why a computational-representational theory is the way it is (the aspirational goal). I examine various questions concerning the prospects for explanatory connections, in particular, including to what extent it makes sense to say that NB could be specialized for particular linguistic computations.

Talk 2: The brain doesn’t care about your experiment.

Sophie Scott1; 1University College London

Functional imaging has made tremendous leaps in our understanding of the functional anatomy of the intact human brain. Is this of importance to our understanding of human language? Some have been skeptical, and others more confident of the insights. In my talk, I will address some of the strengths and limitations of functional imaging and neuroscientific perspectives. Great strengths of this general approach is the ability to move beyond an uncritical dependence and interpretation on Wernicke’s area and Broca’s area as explanatory constructs, and the possibilities of using other neurobiological frameworks and theories to inform linguistic perspectives. More problematic can be the ways that we exploit this, with a very heavy reliance on the kinds of experimental paradigms that are typically essential when performing behavioural studies, but which can lead to spurious patterns of activation, which are not essential to the linguistic phenomena being studied, but which are associated with the task itself. I also would suggest that we have been historically fixated on more abstract aspects of language processing in a way which may have significantly underplayed the social and emotional significance of the spoken or signed word, and I will use the example of speech and voice as a way of demonstrating the effects of this.

Talk 3: Linguistics and cognitive neuroscience: it's time to take diversity seriously.

Fred Dick1; 1Birkbeck College, University of London

The marriage of cognitive neuroscience and linguistics has been a long and productive one. But as with all relationships, it's easy to end up rehashing the same old routines and conversations if you don't make new friends and try out new approaches to old problems. In this regard, cognitive neuroscience can benefit from a more pluralistic and up-to-date view of linguistic research. I'll highlight some recent studies that have successfully used computational approaches to natural language processing as a way to characterize underlying neural representations, and will suggest some ways we can move forward using such approaches. Such detailed models can also give us a way to think about how 'a language brain' might have evolved, and what it means for neuroscientific theories of language when different brains seem to accomplish very basic language tasks in quite different ways. Here, thinking developmentally will be crucial to understand this 'diversity of neural organization', as well as in testing the predictions of linguistic theories. I will highlight some studies on the slow and rather dramatic developmental changes of very basic language skills that suggest that what seems 'easy' according to most linguistic theories is actually something that takes the brain a very long time to sort out to its own satisfaction. Finally, I will discuss how recent work in learning and language evolution bear on a fairly common assumption about language and the brain, namely that the regularities and 'rules' that we can observe in language are actually represented in the brain.


Mini-Symposium Session 2

Sunday, March 29, 10:00 am - Noon, Grand Ballroom B/C

Zooming-in on the hippocampus: Advances in high-resolution imaging in the context of cognitive aging and dementia

Chair: Naftali Raz, Wayne State University
Speakers: Susanne Mueller, Craig Stark, Geoffrey Kirchner, Michael Yassa

Medial temporal lobe circuits play pivotal roles in fundamental cognitive processes and the hippocampal formation is arguably the most researched constituent of the mammalian brain. However, the hippocampus is not a uniform structure and its components or subfields differ dramatically in their cytoarchitectonic, vascular and electrophysiological properties and exhibit differential vulnerability to multiple pathophysiological and neurotoxic factors. The cumulative record of studies in rodents reveals intricate mapping of diverse cognitive operations on specific hippocampal regions, but until recently investigations of similar brain-behavior associations in humans have been rare. Latest advancements in non-invasive magnetic resonance imaging (MRI) techniques allowed progressively finer resolution of hippocampal regional structure and function thus providing cognitive neuroscientists with intriguing opportunities to delve deeper into the neural basis of cognitive differences and changes that accompany aging, development and neurological disease. In this symposium, we will survey the latest developments in MR imaging of the hippocampal subfields, which include four compartments of Cornu ammonis (CA1-CA4), the dentate gyrus, and the subiculum complex. We will present findings pertaining to the role of distinct subfields in specific aspects of episodic memory of healthy adults and persons with cognitive deficits that are linked to multiple pathophysiological and genetic causes.

Talk 1: Insights into Neuroanatomical Correlates of Episodic Memory from Localized Effects of Cerebrovascular Disease

Susanne Mueller1; 1University of California at San Francisco

Vascular risk and cerebrovascular disease increase dramatically with age and are associated with differential decline the hippocampus and its subfields. Thus, cerebrovascular disease presents a useful model for studying episodic memory through investigation of memory deficits arising from disease-related changes in hippocampal structure and function in elderly subjects. In 150 subjects (range: 66-92 years) with and without mild cognitive impairment due to cerebrovascular disease, we obtain high resolution PD-weighted images of the hippocampus that we manual parcellated to obtain subfield volumes from the anterior third of the hippocampal body and entorhinal cortex. We observed smaller CA1 volumes were smaller cognitively impaired participants and were negatively associated with Framingham coronary risk score. Larger CA1-2 transition zone volumes were associated with lower vascular risk. Larger volume of CA1 was associated with better performance on verbal and non-verbal memory tasks but not with an index of global cognition. Thus, vascular disease and vascular risk factors that have been shown to target areas CA1 and CA1-2 are linked to episodic memory performance and may constitute a common substrate for physiological and pathological memory impairment in the elderly.

Talk 2: Differential role of Hippocampal Subfields and Hippocampal Connectivity in Memory

Craig Stark1; 1University of California at Irvine

The hippocampus has long been linked to declarative or explicit forms of memory, but only recently computational models and electrophysiological studies in rodents have associated different memory functions with distinct hippocampal subregions. One particular function, ascribed to the dentate gyrus, is a pattern separation. By transforming similar representations of similar events into discrete representations (pattern separation or orthogonalization), memories can be formed rapidly without suffering high levels of interference. Our understanding of the hippocampus and its role in various forms of memory (e.g., episodic memory, recollection, etc.) would be greatly enhanced if we could translate these computational and rodent studies and provide experimental validation of these findings in humans. Here, I will present data from high-resolution BOLD fMRI studies that are consistent with differential computations across hippocampal subfields. I will further show how healthy aging is associated with a disruption in hippocampal connectivity that is, in turn, associated with alteration of subfield-level activity and memory behavior tied to pattern separation and the dentate gyrus.

Talk 3: Laminar atrophy in the hippocampus and memory deficits

Geoffrey Kirchner1; 1Stanford University School of Medicine

Hippocampal subregions exhibit selective vulnerability to age and neurodegeneration. This selectivity is apparent not only between subfields, but also between laminae, as post-mortem tissue analysis reveals that the neurites in the CA1 stratum radiatum / stratum lacunosum-moleculare (SRLM) are among the first structures in the hippocampus to exhibit neurofibrillary tau pathology in Alzheimer's disease (AD). Using ultra-high field 7-Tesla MRI and 0.22 mm in-plane resolution, we observed differential SRLM atrophy among patients with AD dementia relative to age-matched controls; among older versus younger cognitively-healthy controls; and among carriers of the ApoE4 allele relative to non-carriers. In patients with AD and amnestic mild cognitive impairment (a prodromal stage of AD), there is a robust and specific correlation between the degree of SRLM atrophy and episodic memory performance, consistent with the notion that loss of synaptic structures in this neuropil region of the hippocampus relates to a core cognitive feature of AD. SRLM atrophy reflects the burden of tau-related neuropathology, as measured by cerebrospinal fluid tau and phospho-tau levels. In summary, quantitative evaluation of hippocampal laminar structure yields important insights into the selective vulnerability SRLM to aging and AD-related neurodegeneration, and its close association with molecular biomarkers and behavioral performance.

Talk 4: Dissecting Hippocampal Computations and Processes: A Translational Perspective Using High-Resolution fMRI

Michael Yassa1, Zachariah Reagh1; 1University of California at Irvine

There has been widespread interest recently in distinguishing the roles that particular hippocampal subfields play in service of episodic memory storage. This is compounded with the fact that subfield-specific patterns of pathology are expressed in the context of various mental disorders including, aging, AD, and depression. I will discuss our recent work in (1) delineating the computational roles various hippocampal subfields play with a particular emphasis on the dentate gyrus and CA3 regions, (2) the interactions of these subfields with other medial temporal lobe regions in the context of specific types of memory, (3) differential vulnerability of hippocampal subfields to aging, AD, and depression, and (4) using subfield-level MRI to derive novel biomarkers for early prediction of disease and treatment outcomes.


Mini-Symposium Session 3

Sunday, March 29, 10:00 am - Noon, Bay View Room

Reasoning: Origins and Development

Chair: Kathy Mann Koepke, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)/NIH
Speakers: Aaron Blaisdell, Silvia Bunge, Ben Rottman, Daniel Krawczyk

Despite great neuroscience advances, pursuit of the mechanisms underlying reasoning abilities has stalled. Without clear models, universal definitions, or normative data on which to build rich, heuristic theoretical models of reasoning, the search for clear neurobiological and genetic underpinnings has been slow. Understanding how reasoning skills develop; identifying developmental challenges, sensitive periods, risks and key prevention, maintenance, and remedial interventions have emerged as critical priorities. Refining nomenclature, developing homologous cross-species measurements, identifying sophisticated analytic methods that incorporate developmental, neurobiological, social and environmental factors, and building predictive theories of real-world reasoning are urgently needed. To this end, NICHD has called together a multidisciplinary work group of leading scientists to identify current knowledge and advancement gaps in reasoning research. Speakers will present current research and focus attention on issues identified by the work group that can be addressed in both the short and longer term before the field can significantly advance. Aaron Blaisdell will introduce evidence of pigeon spatial- and rat causal-inferences, the value and utility of animal models of reasoning. Silvia Bunge will explore brain changes associated with developing reasoning ability and how brain plasticity might be manipulated to improve reasoning. Ben Rottman will examine how people make sophisticated causal inferences with incomplete information. Daniel Krawczyk will introduce the disordered reasoning witnessed in Autism Spectrum Disorder and Traumatic Brain Injury, the underlying neural perturbations, and the clinical implications of disordered reasoning. In each case, the speakers’ own research will both highlight new understanding and important gaps in reasoning research.

Talk 1: Comparative behavioral neuroscience of reasoning processes.

Aaron Blaisdell1; 1UCLA

Reasoning has long been thought to be a uniquely human capacity, but it did not appear de novo in our species. Rather, reasoning is found in a wide spectrum of primate and non-primate species. In this talk, I will review just some of the many elements of reasoning that are found in nonhumans, focusing on experiments in rats and pigeons. I will discuss my own work on spatial inferences in pigeons and causal inferences and imagery in rats, including the neural circuitry that is involved in reasoning about absent events. Despite this increased sophistication in our understanding, the neural basis of reasoning in animals has received inadequate attention. Further, very recent discoveries of deep homologies at the cell-molecular level for many of the brain/cognitive phenotypes seen in humans will be discussed, linking their ancestry far back in evolutionary time. These new cell-molecular mechanisms provide a window to study ontogeny of cognition and an opportunity to fill knowledge gaps. Animal models, such as the rat and the pigeon, can provide valuable tools to investigate the role of neurodevelopmental processes and life-history experience in the establishment of the adult form of reasoning. Animal models can be interrogated at the cell-molecular, neural circuit, behavioral, and computation levels of analysis. Thus, with the advent of more sophisticated neuroimaging and neuromanipulation techniques and assessment of neurogenetics during development, the field of development of reasoning is poised to enter a renaissance and dramatically improve our understanding of human cognitive development and dysfunction.

Talk 2: Neural mechanisms, development, and plasticity of reasoning

Silvia Bunge1; 1University of California at Berkeley

Reasoning, the ability to think logically and solve novel problems, is a prerequisite for scholastic achievement. Despite – or because of – its central role in theories of human intelligence, reasoning has in recent years fallen out of research favor. As the United States slips behind other industrialized nations in mathematics and science achievement, it is time to revisit reasoning research with a fresh perspective. First I will briefly review evidence that various forms of deductive reasoning recruit overlapping regions within the lateral frontoparietal network (LFPN). Specifically, the inferior parietal lobule and rostrolateral prefrontal cortex play key roles in relational reasoning; I will suggest that their contributions may be domain-general. I will then report on longitudinal brain imaging in children ages 6-21, identifying structural and functional changes within the LFPN that best predict the growth of reasoning ability over childhood and adolescence. Next, I will show that 3 months of intensive practice of reasoning skills leads to structural and functional changes in the LFPN in young adults. Finally, I will describe how we are using eyetracking methodology and lateralized stimulus presentation techniques to gain novel insights into how people reason. These studies point to the need for further exploration of: (1) domain-general and domain-specific brain mechanisms that support reasoning, (2) changes in brain structure and function that support optimal reasoning development over childhood and adolescence, (3) the extent to which reasoning skills can be improved via experience-dependent brain plasticity, and (4) approaches for monitoring and predicting the growth of reasoning.

Talk 3: Causal Reasoning: The Role of Temporal Heuristics for Sophisticated Inferences

Ben Rottman1; 1University of Pittsburgh

When learning and reasoning about causal relationships, people are faced with an extremely challenging and underdetermined problem. For example, people often do not know how the data were generated or have misconceptions about the data, and different beliefs and assumptions can lead to different inferences. In the last 15 years, Bayesian models of causal learning originally developed by computer scientists and philosophers have been applied and extended as models of human causal reasoning. Bayesian models are extremely flexible and explain how a rational agent should incorporate knowledge and beliefs when learning in a new situation. However, much of this research has ignored the process or algorithmic-level description of human causal reasoning, focusing exclusively on the computational level. I will discuss research showing that people often make highly sophisticated and flexible causal inferences that go beyond the typical assumptions of most learning algorithms. Yet, these inferences are intuitive and amenable to simple heuristics. Many of these inferences rely upon subtle temporal cues to causality. Furthermore because they unfold over time, these inferences are easily interpretable with algorithmic explanations. At the same time, these inferences often provide insight into pre-existing assumptions and beliefs people have when engaging in causal reasoning, and can inform a Bayesian or computational-level analysis. New models of probabilistic reasoning are reshaping the field of reasoning in dramatic and important ways. To develop a thorough understanding of causal reasoning and probabilistic reasoning more generally, future research will need to integrate heuristic and algorithmic-level explanations with computational-level explanations of reasoning.

Talk 4: Clinical implications for deficits of reasoning: Evidence from Autism Spectrum Disorders and Traumatic Brain Injury

Daniel Krawczyk1; 1University of Texas at Dallas and the University of Texas-Southwestern Medical Center

Reasoning depends on multiple factors including perceiving the relevant context, recall of appropriate knowledge to a given situation, and inference processes. Neuroscience studies have begun to contribute to several of these processes by specifying the conditions when they are engaged and mapping cognition to neural systems. I will discuss examples from three lines of research that illustrate important correspondences between cognitive processes and neural function. First, neuroimaging studies provide converging evidence for the importance of the prefrontal cortex and its functional connections in governing relational perception, the verification of rules, and generating inferences. Second, evidence from adolescents demonstrates that perceiving similarity at multiple levels is needed for abstract reasoning. Such abilities are disrupted in clinical conditions such as traumatic brain injury, and conditions affecting social perception such as autism and schizophrenia. Lastly, neuroimaging studies of expertise highlight the importance of our knowledge of previous successes. Together these approaches provide a more complete picture of the abilities important for reasoning as well as the multiple brain regions and interconnectivity that supports reasoning. Despite our progress to date, there has not been adequate agreement within the field about the key sub-processes that contribute to reasoning. Neuroscience evidence can help to achieve greater clarity on these sub-processes. To achieve this end the research community will need to seek methods that will provide both experimental control and the ability to scale research to simulate the complexity faced in real world reasoning, including social factors, multi-tasking, and the limits of human expertise.


Mini-Symposium Session 4

Monday, March 30, 10:00 am - Noon, Grand Ballroom A

Cerebellar Contributions to Learning and Cognition

Chair: Rich Ivry, University of California, Berkeley
Co-Chair: Arseny Sokolov, Centre Hospitalier Universitaire Vaudoi
Speakers: Rich Ivry, Aparna Suvrathan, Arseny Sokolov, Julie Fiez

This symposium will provide an overview of current ideas concerning the contribution of the cerebellum to learning and cognitive processing. Recent findings from neurophysiology, neuropsychology and brain imaging have led to significant changes in our understanding of the mapping and function of the cerebellum. The symposium will feature an interdisciplinary panel of speakers who will present state-of-the-art research, diverse views and approaches employed to understand cerebellar contributions to learning and cognition. Ivry will discuss the role of the cerebellum in motor learning, and ask how computational principles derived from this work may help explain non-motor functions of this structure. Suvrathan will describe physiological work that addresses how synaptic learning rules are implemented by the cerebellar circuit. Sokolov will present lesion and imaging evidence on the interaction between the cerebellum and temporal cortex during the visual perception of action. Fiez will address the role of the cerebellum in the development of skilled reading, also drawing on lesion and neuroimaging data. The speakers will integrate their talks to consider general principles of intracerebellar processing and cerebellar-cortical communication. The symposium should be of substantial interest to the cognitive neuroscience community, providing fresh ideas on the interaction between the cerebellum and cortex, one that has attracted considerable interest in literatures as diverse as motor control, cognition, psychiatry and development.

Talk 1: The Predictive Brain: Cerebellar Contributions to Action and Cognition

Rich Ivry1; 1University of California, Berkeley

Sensorimotor learning can be studied by asking participants to move in novel workspaces in which they encounter novel forces or systematic distortions of visual feedback (e.g., where the visual feedback is translated or rotated in space). In such tasks, people adapt a sensorimotor map to implicitly compensate for the perturbation. Patients with cerebellar degeneration exhibit a pronounced impairment on such tasks. This learning impairment does not appear to be directly related to problems in motor control per se, but rather in generating expectancies of the sensory consequences of the movements. These expectancies are compared with the actual feedback to generate sensory prediction errors, a signal used to adapt an internal model of the workspace. Recent work has highlighted the obligatory and modular nature of this cerebellar learning system; for example, error-based learning from sensory prediction errors continues to occur even under conditions in which this process is maladaptive. A failure to generate and utilize sensory predictions has also been observed in people with psychiatric disorders such as autism and schizophrenia, conditions in which there is consistent evidence of cerebellar pathology. This work suggests a computational hypothesis concerning how cerebellar dysfunction might contribute to the cognitive deficits observed in these psychiatric populations, as well as a more general view of cerebellar function in healthy individuals.

Talk 2: Tuning of Synaptic Plasticity for Cerebellar Learning

Aparna Suvrathan1, Jennifer Raymond1; 1Stanford University

A broad goal in neuroscience is to understand how the features of behavior and cognition are shaped by the properties of neurons and synapses. Our lab is studying how the neural learning algorithms emerge from, and are shaped by local rules controlling the induction of plasticity at different synapses within the circuit. It has been widely assumed that the plasticity rules are uniform across a given brain structure. For example, the cerebellum is composed of clearly distinct functional zones, with different behavioral roles and hence computational requirements, yet models linking synaptic plasticity mechanisms to cerebellar learning have been based largely on the synaptic properties reported in one small, physiologically accessible region of the cerebellum. We directly compared the synaptic learning rules at equivalent synapses in different functional zones of the cerebellum, and found striking differences. These differences seem to reflect tuning of the plasticity mechanisms for the computational requirements of the specific kinds of learning implemented by each zone.

Talk 3: Interactions Between the Cerebellum and Temporal Cortex During Action Perception

Arseny Sokolov1; 1Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland

Visual perception of human actions is indispensable in our everyday life. Observation of biological motion subserves motor learning, car driving and non-verbal social communication. While the cortical system for action observation has been studied in great detail, subcortical contributions to action understanding have received minimal attention. Our data from neurosurgical patients with tumors to the cerebellum indicate that the integrity of left lateral cerebellar structures is essential for the veridical perception of body motion. Several lines of neuroimaging evidence provide converging evidence in support of this hypothesis. 1) Activity in the left lateral cerebellar lobules Crus I and VIIB in healthy adults is related to action observation. 2) Dynamic causal modelling reveals reciprocal communication between the left lateral cerebellum and the right superior temporal sulcus, a key structure of the cortical networks for action observation and social cognition. 3) A direct structural pathway between these regions can be identified with diffusion tensor imaging. 4) Recovery of biological motion processing after cerebellar tumor removal is paralleled by topographical reorganization in the corresponding cerebro-cerebellar network. In summary, lesion and multimodal imaging evidence illustrate the role of the cerebellum in the circuitry for visual processing of body motion. The findings open a window for further research on interactions between the cerebellum and temporal cortex in social cognition, multimodal integration, language processing, and in neuropsychiatric conditions, such as multiple sclerosis, epilepsy, schizophrenia or autistic spectrum disorders.

Talk 4: Contributions of the Cerebellum to Reading Development

Julie Fiez1; 1University of Pittsburgh

Neurobiological studies of developmental dyslexia have focused predominantly on regions in a dorsal temporo-frontal pathway associated with phonological analysis and speech production, and its interconnections with a putative visual word form area in the mid-fusiform gyrus. However, recent work has provided renewed support for a cerebellar deficit hypothesis of developmental dyslexia proposed 20 years ago. Despite increased evidence in support of this hypothesis, the functional role of the cerebellum in normal and disordered reading remains poorly understood. To gain traction on this issue, a task overlap approach was used to identify cerebellar regions that are active in normal readers learning new visual word forms, and also in two tasks in which normal performance correlates with reading skill (rhyme judgment, immediate serial recall). Based upon the results of this analysis, it is suggested that orthographic learning makes use of a decoding scaffold that involves speech motor planning, with the cerebellum contributing a phonological error-monitoring component to this scaffold. This interpretation is explored through convergent work involving participants with focal lesions to the cerebellum. Phonological analysis and orthographic learning deficits in this population provide support for a phonological monitoring account of cerebellar contributions to orthographic-phonological mapping. Together, the imaging and lesion results provide a neuroanatomical basis for the self-teaching hypothesis of reading (Share, 1995) and a theoretical framework for understanding the role of the cerebellum in the development of skilled reading.


Mini-Symposium Session 5

Monday, March 30, 10:00 am - Noon, Grand Ballroom B/C

Disrupting the face perception network

Chair: David Pitcher, NIMH
Speakers: Arash Afraz, Marlene Behrmann, David Pitcher, Kevin Weiner

Faces are rich sources of social information that simultaneously convey someones identity, attentional focus, and emotional state. Our visual system is so efficient that, to us, processing this information appears to happen effortlessly. Yet the simplest functions, like recognizing your mother or judging her mood, depend on interactions across a network of specialized brain regions. Despite many years of study our understanding of the unique functions performed by each region and how these regions interact to facilitate face perception remains limited. The speakers in this symposium use novel combinations of experimental techniques to study the behavioural effects of disruption in the face perception network. Our aims are to update the fundamental understanding of how faces are cortically represented and to establish common theoretical ground among researchers. To achieve this we will present studies using a range of subject populations (healthy-humans, brain-damaged patients, pre-operative epileptic patients and non-human primates) and experimental methods (optogenetics, fMRI, microstimulation, physiology, TMS, diffusion weighted imaging and neuropsychology). We believe this symposium will be of great interest to CNS attendees for two reasons. Firstly, understanding the neural processes underlying face perception has proven to be a testing ground in which key disputes concerning anatomical specificity and computational modularity take place and which therefore generates great interest amongst all cognitive neuroscientists. Secondly, studying the face network serves as a proxy for studying the whole brain as a network and we believe attendees will be eager to apply the experimental techniques discussed to address their own questions.

Talk 1: The causal role of face-selective neurons in face perception.

Arash Afraz1; 1Massachusetts Institute of Technology

Many neurons in the inferior temporal cortex (IT) of non-human primates respond more strongly to images of faces than to images of non-face objects. Such so-called “face neurons” are thought to be involved in face recognition behaviors such as face detection and face discrimination. While this view implies a causal role for face neurons in such behaviors, the main body of neurophysiological evidence to support it is only correlational. Here, I bring together evidence from electrical microstimulation, optogenetic and pharmacological intervention in macaques to bridge the gap between the neural spiking of IT face selective neurons and face perception.

Talk 2: Reverse engineering the face perception system: insights from congenital prosopagnosia

Marlene Behrmann1; 1Department of Psychology, Carnegie Mellon University, USA

Reverse engineering involves disassembling a complex device and analyzing its components and workings in detail with the goal of understanding how the device works in its intact state. To elucidate the neural components implicated in normal face perception, we investigate the disrupted components in individuals with congenital prosopagnosia, an apparently lifelong impairment in face processing, despite normal vision and other cognitive skills. Structural and functional MRI data reveal compromised connectivity between more posterior face-selective cortical patches and more anterior regions that respond to face stimuli. Computational descriptions of the topology of this connectivity, using measures from graph theory that permit the construction of the network at the level of the whole brain, uncover atypical organization of the face network in CP. Moreover, this network disorganization is increasingly pronounced as a function of severity of the face recognition disorder. Last, we reconstruct the face images viewed by normal and prosopagnosic observers from the neural data and demonstrate the altered underlying representations in key cortical regions in the prosopagnosic individuals. This multipronged approach uncovers in fine-grained detail the alteration in information discrimination in the prosopagnosic individuals as well as the pertubations in the neural network that gives rise to normal face perception.

Talk 3: Transient disruption in the face perception network: combining TMS and fMRI

David Pitcher1; 1National Institute of Mental Health

Faces contain structural information, for identifying individuals, as well as changeable information, that can convey emotion and direct attention. Neuroimaging studies reveal brain regions that exhibit preferential responses to invariant or changeable facial aspects but the functional connections between these regions are unknown. This issue was addressed by causally disrupting two face-selective regions with thetaburst transcranial magnetic stimulation (TBS) and measuring the effects of this disruption in local and remote face-selective regions with functional magnetic resonance imaging (fMRI). Participants were scanned, over two sessions, while viewing dynamic or static faces and objects. During these sessions, TBS was delivered over the right occipital face area (rOFA) or right posterior superior temporal sulcus (rpSTS). Disruption of the rOFA reduced the neural response to both static and dynamic faces in the downstream face-selective region in the fusiform gyrus. In contrast, the response to dynamic and static faces was doubly dissociated in the rpSTS. Namely, disruption of the rOFA reduced the response to static but not dynamic faces, while disruption of the rpSTS itself, reduced the response to dynamic but not static faces. These results suggest that dynamic and static facial aspects are processed via dissociable cortical pathways that begin in early visual cortex, a conclusion inconsistent with current models of face perception.

Talk 4: The human face processing network is resilient after resection of specialized cortical inputs

Kevin Weiner1; 1Department of Psychology, Stanford University

Functional hierarchies are a prevalent feature of brain organization. In high-level visual cortex, the “occipital face area” (OFA/IOG-faces) is thought to be the input to a specialized processing hierarchy subserving human face perception. However, evidence supporting or refuting the causal role of IOG-faces as a necessary input to the face network evades researchers because it necessitates a patient with a focal lesion of the right inferior occipital cortex, as well as functional measurements both before and after surgical removal of this region. Here, in a rare patient fulfilling both of these requirements, we show that the face network is surprisingly resilient in two ways following surgical removal of IOG-faces. First, the large-scale cortical layout and selectivity of the face network are stable after removal of IOG-faces. Second, following resection, face-selective responses in ventral temporal cortex surprisingly become more reliable in the resected hemisphere, but not in the intact hemisphere. Further investigations of the anatomical underpinnings of this resiliency using diffusion tensor imaging suggest the existence of additional white matter pathways connecting early visual cortex to downstream face-selective regions independent of IOG-faces. Thus, after resection, neural signals can still reach downstream regions via these pathways that are largely unconsidered by present neurofunctional models of face processing. Altogether, these measurements indicate that IOG-faces is not the key input to the face network. Furthermore, our results pose important constraints on hierarchical models in high-level sensory cortices and provide powerful insight into the resiliency of such networks after damage or cortical trauma.


Mini-Symposium Session 6

Monday, March 30, 10:00 am - Noon, Bay View Room

Approaches to identify network connectivity in neuroimaging

Chair: Vaughn Steele, The Mind Research Network
Co-Chair: Vince Calhoun, The Mind Research Network
Speakers: Vaughn R. Steele, Edward M. Bernat, Selin Aviyente, Vince D. Calhoun

Connectivity measures are widely used to identify neural correlates of cognitive functions, however many approaches ignore the possibility of time-varying connectivity. We present a series of talks which provide approaches that move beyond such static measures and capture transient or recurring patterns of connectivity. Whole brain connectivity analyses of cognitive control tasks will be presented for electroencephalogram (EEG), event-related potential (ERP), and functional magnetic resonance imaging (fMRI) data. First, we will review steps to ensure reliable cognitive control related signal in both ERP and fMRI. We replicate and extend previous reports by including both ERP and fMRI analysis with stabilization techniques such as bootstrapping and subsampling. Two of the talks are based on a recently proposed complex Cohen’s class time-frequency distribution (Aviyente et al., 2011) to calculate phase-locking values (PLV) providing improved time-frequency resolution. The first utilizes bivariate PLV measures, demonstrating sensitivity to cognitive and motor processes in several active task paradigms. The next talk introduces a multivariate tensor-based dynamic functional connectivity tracking framework to provide a data-driven approach to characterizing changes in network connectivity across time and to determine the different network states during cognitive control based on EEG data. Finally, we will discuss methods related to dynamic functional connectivity of fMRI data using independent component analysis. This includes approaches to both estimation and characterization of recurring patterns of connectivity ‘states’ which may overlap as well as global measures of state behavior ‘meta-states’. Taken together, we summarize practical steps for characterizing intrinsic networks measured using EEG, ERP, and fMRI.

Talk 1: Neuroimaging measures of cognitive control: Extracting reliable signals

Vaughn R. Steele1, Edward M. Bernat2, Vince D. Calhoun1, Kent A. Kiehl1; 1The Mind Research Network, 2University of Maryland

Reliability of measured signal has long been a concern for researchers using event-related potential (ERP) and functional magnetic resonance imaging (fMRI). Using ERP data, reliability measures have been explored in neural correlates of cognitive control (i.e., response inhibition and error-monitoring) suggesting the necessity of 6 to 8 trials. However, identifying the number of trials needed for reliable cognitive control signal measured in fMRI and number of participant needed in each modality has yet to be fully examined. Datasets of healthy participants (ERP n=137; fMRI n=102) who performed a Go/NoGo task were analyzed to replicate and extend previous reports. Specifically, we sought to identify the necessary number of trials and participants needed to achieve reliable cognitive control signal in each neuroimaging modality. Measures related to a false alarm (error-monitoring) were extracted for analysis from ERP (error-related negativity [ERN] and error positivity [Pe]) and fMRI (anterior-cingulate cortex activation) data. For each modality, Cronbach’s alpha became consistent at a similar number of trials (6-8) and number of participants (30-50). Stabilization techniques (i.e., bootstrapping and subsampling) were also used to extract subject-level data for comparison. In addition to these extracted values, simulations were included to highlight advantages when applied to analysis of network connectivity (i.e., characterizing complex patterns of activation among interconnected brain regions). Therefore, we outline best-practices in measuring reliable error-monitoring signals in both ERP and fMRI with respect to the necessary number of trials and participants. Also, we review advantages of using stabilization techniques specifically for analysis of network connectivity.

Talk 2: Indexing Dynamic Functional Integration using Bivariate Time-Frequency Phase-Synchrony with Event-Related Potential Data

Edward M. Bernat1, Selin Aviyente,2, Andrey Anokhin2, Jason Moser3, N. B. Schmidt4; 1University of Maryland, 2Washington University School of Medicine, 3Michigan State University, 4Florida State University

Dynamic functional integration of brain regions during task performance is an important emerging topic of study. Recent work with ERPs has begun to demonstrate the utility of time-frequency (TF) phase-synchrony (PS) approaches for indexing functional integration. Based on a recently developed TF-PS distribution (Aviyente et al., 2011), the work to be presented provides evidence that this TF-PS measure can successfully index dynamic functional integration associated with relevant cognitive and affective processing involving medial-prefrontal (mPFC), lateral-prefrontal (lPFC), motor, and occipital regions. Findings from four studies will be detailed. The first is a longitudinal study of adolescents (at ages: 12, 14, 16; N=214) engaged in a gambling task. Findings indicate that dynamic mPFC-lPFC and lPFC-motor functional integration increases significantly during this period of development. The second study (N=95) investigates functional integration during a common go/no-go task. Here greater mPFC-lPFC integration is observed for no-go trials, and greater mPFC integration with contralateral motor areas during response execution (go) and inhibition (no-go). The final two studies involve clinically-relevant individual differences. In the first (N=94), increases in worry (Penn State Worry Questionnaire, PSWQ) are independently associated with increased error-related negativity (ERN) amplitude and a decrease in mPFC-lPFC functional integration. The fourth study (N=85, collection ongoing) involves gambling feedback ERP data from anxiety patients who have varying levels of suicidal thoughts and urges. Results indicate that both amplitude and mPFC-lPFC TF-PS are related to level of suicidal presentation. Broadly, findings validate the bivariate PLV measure, and provide motivation for the development of multivariate approaches.

Talk 3: A tensor-based approach to tracking dynamics of functional connectivity in the brain

Selin Aviyente1, David Zoltowski1, Arash Mahyari1, Edward M. Bernat2; 1Michigan State University, 2University of Maryland

With the advances in neuroimaging technology, it is now possible to collect multi-channel neurophysiological signals such as electroencephalogram (EEG) data across different experimental conditions and subject groups. In this talk, we propose tensor tracking and compression algorithms to identify change points in network topography and to summarize the quasi-stationary network states. Tucker decomposition of the functional connectivity networks across frequency bands, subjects and time allows us to capture the variation of these higher order datasets using a few orthogonal factors. Using lower rank approximations to the tensor at each time point and subspace distance metrics to quantify the change in the network across time, we identify the change points. Once the change points are detected, each time interval is compressed to a single network state representation through tensor-matrix projection and sparsity optimization. The proposed dynamic functional connectivity network tracking methods are applied to EEG data collected during a study of cognitive control in the brain. The results indicate that during error processing, the brain’s network organization across time and subjects can be efficiently described using 5 distinct network states in the theta (2-5Hz) frequency band, where the network states closely align with the subject’s response time, onset of error-related negativity (ERN) and onset of the error positivity (P3e). Moreover, the topographic summarization of these network states indicates activation of broader brain regions before the response and more specialized and sparse activation patterns during ERN in particular between the medial prefrontal cortex (mPFC) and lateral prefrontal cortex (lPFC).

Talk 4: The chronnectome: time-varying connectivity networks as the next frontier in fMRI data discovery

Vince D. Calhoun1, Vaughn R. Steele1; 1The Mind Research Network

Recent years have witnessed a rapid growth of interest in moving functional magnetic resonance imaging (fMRI) functional connectivity investigations beyond simple scan-length averages and into approaches that capture time-varying properties of connectivity. In this perspective we use the term “chronnectome” to describe such metrics that allow a dynamic view of coupling. In the chronnectome, coupling refers to possibly time-varying levels of correlated or mutually informed activity between brain regions whose spatial properties may also be temporally evolving. We primarily focus on multivariate approaches developed in our group, and review a number of such approaches with an emphasis on matrix decompositions such as principle component analysis and independent component analysis. We also discuss the potential these approaches offer to improve characterization and understanding of brain function, which is inherently dynamic, not-well understood, and thus poorly suited to conventional scan-averaged connectivity measurements. We show examples of how dynamic connectivity can provide important information for both resting fMRI and task-based fMRI (e.g. go/nogo task) data. There are a number of methodological directions which need to be developed further, but chronnectome approaches already show great promise for the study of both the healthy and diseased brain.


Mini-Symposium Session 7

Monday, March 30, 3:30 - 5:30 pm, Grand Ballroom B/C

Interactions Between the Prefrontal Cortex and the Medial-Temporal Lobes Supporting the Control of Memory Retrieval

Chair: Michael Anderson, University of Cambridge
Co-Chair: David Badre, Brown University
Speakers: Helen Barbas, Michael Anderson, David Badre, Howard Eichenbaum

Although memory retrieval often occurs automatically, adaptive behavior frequently recruits cognitive control processes that guide retrieval in a goal directed manner. Sometimes this control demand arises because memories may be difficult to retrieve, due to interference or other factors; other times, the retrieval process itself may need to be suppressed to support cognitive or emotional goals. Moreover, the products of retrieval need to be monitored for adaptive outcomes. Whereas episodic retrieval depends on medial temporal lobe (MTL) systems, the cognitive control of memory retrieval is known to require the prefrontal cortex (PFC), and it is widely believed that cognitive control over memory is achieved by PFC-MTL interactions. Despite this, relatively little is known about the nature of these interactions or the pathways that support them. In this symposium, we examine the nature of PFC-MTL interactions, the pathways mediating them, computations performed, and the mnemonic functions they serve. To address this issue, we bring together research with diverse methods and perspectives, ranging from work with functional and structural imaging with humans, to anatomical studies in non-human primates, and single unit electrophysiology studies of fronto-hippocampal interactions in rodents. We further examine both excitatory and inhibitory modulations of MTL function, in support of the controlled use of memory.

Talk 1: Primate prefrontal pathways to rhinal areas affect the input and output of the hippocampus and memory

Helen Barbas1; 1Boston University

How does information from prefrontal cortices influence memory-related medial temporal cortices? Robust pathways from the anterior cingulate cortex (ACC), associated with the contextual significance of stimuli, innervate the entorhinal cortex, the gateway to the hippocampus. On the other hand, the posterior orbitofrontal cortex (pOFC), associated with the affective value of stimuli, innervates mostly adjacent perirhinal area 36. Both pathways innervate all layers of the respective cortices, suggesting direct or indirect influence on the upper (input) and deep (output) layers of the hippocampus. Both pathways innervate mostly excitatory neurons and smaller though significant proportions innervate inhibitory neurons in the respective rhinal cortices. Among the latter, in the upper layers of the entorhinal cortex the ACC pathway innervates the neurochemical class of calretinin inhibitory neurons, which have disinhibitory influence on nearby excitatory pyramidal neurons, suggesting facilitated passage to the hippocampus. On the other hand, in the upper layers of area 36 the pOFC pathway innervates preferentially calbindin inhibitory neurons, which are synaptically suited to reduce noise and enhance signal, suggesting facilitated focus on relevant stimuli and filtering out noise. In the deep rhinal layers, which receive the output of the hippocampus, both ACC and pOFC pathways innervate preferentially the powerful parvalbumin inhibitory neurons which provide strong perisomatic inhibition of nearby excitatory neurons. These findings suggest that ACC and pOFC pathways facilitate access of stimuli with contextual and affective significance to the hippocampus, but gate hippocampal output to the cortex and may determine which memories endure.

Talk 2: A right dorsolateral prefrontal pathway supports the suppression of mnemonic functions in the hippocampus

Michael Anderson1, Taylor Schmitz1, Catarina Ferreira2; 1University of Cambridge, 2University of Granada

Although memory for the past is usually viewed as desirable, our cognitive and affective goals often require us to limit the accessibility of unwanted memories. For example, people clearly limit the time they spend thinking about unpleasant experiences, a process that begins during encoding, but that continues when cues later remind someone of the unwelcome memory. In this talk, I will review the emerging behavioral and neuroimaging evidence that stopping the episodic retrieval process to suppress awareness of an unwelcome memory is achieved by a supramodal inhibitory control mechanism mediated by the right dorsolateral prefrontal cortex. This mechanism overlaps with mechanisms involved in motor response suppression. Functional and effective connectivity analyses indicate that this top-down control mechanism interacts with medial-temporal lobe structures, disrupting traces that support retention. This mnemonic stopping mechanism acts to globally suppress neural activity in the hippocampus, likely via GABA-ergic interneurons, disrupting both retrieval and encoding processes in non-specific fashion. These findings indicate that the fundamental mnemonic functions of the hippocampus are subject to strategic regulation, and that such regulation introduces lasting biases in which life events remain accessible

Talk 3: Separable ventral and dorsal frontal pathways supporting cognitive control during retrieval.

David Badre1; 1Brown University

It has been well established that memory retrieval performance can be improved through strategic processes. These strategic processes are supported by executive or cognitive control systems that depend, in part, on the frontal lobes. However, the pathways by which frontal cortex can influence memory retrieval, such as in the medial temporal lobe system, remains under specified. In this talk, I will discuss a line of recent studies using human imaging that investigate the pathways linking prefrontal cortex with MTL during the cognitive control of memory. First, I will describe a set of fMRI and functional connectivity experiments demonstrating a functional dissociation between ventral versus dorsal pathways related to control over access to memory versus control over responding. Then, I will provide evidence from high angular resolution diffusion tractography that elaborates the organization of these pathways in the human brain.

Talk 4: An animal model system for understanding prefrontal-hippocampal interactions in memory retrieval

Howard Eichenbaum1; 1Boston University

In humans, in interactions between the prefrontal cortex (PFC) and hippocampus support the retrieval of memories that are relevant to the current context. Here I will outline a rodent model system in which prefrontal-hippocampal interactions can be explored at the level of information coding by neuronal ensembles and local field potentials within these brain areas. Similar to neuropsychological findings in humans, damage to the hippocampus in rats increases forgetting whereas damage to PFC results in failure to suppress context-inappropriate memories. Consistent with these findings, representational similarity analysis reveals that the dorsal (posterior in humans) hippocampus creates a systematic organization of highly specific memories within a context, whereas the ventral (anterior) hippocampus generalizes across memories within a context and strongly distinguishes between memories from different contexts. Furthermore, PFC inactivation reduces the ability of the dorsal hippocampus to suppress inappropriate memory representations, consistent with the behavioral findings on PFC damage. Finally, analysis of the flow of information through the system reveals how bidirectional communication between PFC and the hippocampus supports memory. This analysis showed that, during context-cued memory retrieval, contextual cues initially processed by the ventral hippocampus are sent to PFC, likely via well-known monosynaptic projections; then PFC controls retrieval of memory representations in the dorsal hippocampus by suppressing the activation of context-inappropriate neural and behavioral responses. These findings converge on an understanding, at the cellular level, of fundamental prefrontal-hippocampal interactions that are common across species and domains of declarative memory.


Mini-Symposium Session 8

Tuesday, March 31, 10:00 am - Noon, Grand Ballroom A

Temporal coordination of neuronal processes by cross-frequency interactions

Chair: Ole Jensen, Donders Centre for Cognitive Neuroimaging
Speakers: Sara Szczepanski, Peter Lakatos, Hyojin Park, Ole Jensen

Electrophysiological brain activity is dominated by oscillatory activity during cognitive tasks. The oscillations have been reported in various brain regions and covers a wide range of frequencies. These oscillations are believed to orchestrate neuronal processing and the functional connectivity between brain regions. While oscillations in different bands have been well-characterized over the years, it remains less clear how they interact. Typically robust phase-to-power interactions between slower and faster oscillations have been reported in various kinds of task and species. Examples are delta-to-gamma coupling in auditory cortex, alpha-to-gamma couplings in visual regions and theta-to-gamma couplings in the hippocampus. Most likely the slower oscillations serve to coordinate neuronal processing reflected in higher frequencies bands. The goal of this symposium is to undercover the state-to-the-art of cross-frequency couplings identified in various cognitive states and tasks. This will be done in the context of studies on intracranial recordings in non-human primates and MEG and ECoG recordings in humans. In particular it will be addressed how cross-frequency interactions serve to support cognition by organizing neuronal processing over different temporal scales.

Talk 1: Dynamic Fronto-Parietal Interactions During Attentional Control

Sara Szczepanski1, Rachel Kuperman2, Kurtis Auguste2,3, Josef Parvizi4,5, Robert Knight1; 1University of California, Berkeley, 2Children's Hospital and Research Center, Oakland, CA, 3University of California, San Francisco, 4Laboratory of Behavioral and Cognitive Neurology, 5Stanford University, 6

Attention, critical to visual perception and goal-directed behavior, enables allocation of limited resources depending on current task demands. Frontal and parietal cortical areas, referred to as the fronto-parietal attentional control network, are crucial for controlling the attentional selection process. Although numerous studies have examined the functions of this network using various neuroimaging techniques, considerably less is known about how these frontal and parietal areas interact dynamically to produce behavior on a fine spatio-temporal scale in humans. We examined the temporal dynamics and interactions within and between regions of the fronto-parietal network using electrocorticography (ECoG). ECoG signals were measured directly from subdural electrodes implanted in patients undergoing intracranial monitoring for localization of epileptic foci. Subjects (n=8) performed a dynamic reaction time task, requiring attentional allocation to either the right or left visual field and detection of targets. Phase-amplitude coupling (PAC) between high gamma power (70-250 Hz) and delta/theta phase (2-5 Hz) within electrodes over frontal, parietal, and occipital cortex increased when subjects attended to the contralateral (vs. ipsilateral) visual field. These PAC modulations tracked attentional performance across single trials. We also found significant increases in phase coherence in the delta (2-4 Hz) and theta (5-8 Hz) frequency bands between intrahemispheric frontal, parietal, and visual electrodes that was enhanced for attention to the contralateral (vs. ipsilateral) visual field. These results highlight the roles of PAC and phase coherence as mechanisms for coordination within and between human fronto-parietal and visual areas, which adjust parameters on a sub-second basis depending on momentary attentional demands.

Talk 2: Slow modulation of cross-frequency oscillatory dynamics in thalamocortical networks

Peter Lakatos1,2, Annamaria Barczak1, Monica O'Connell1; 1Nathan Kline Institute, Orangeburg, NY, 2NYU School of Medicine

When temporally regular stimulus sequences are attended, the brain’s rhythmic excitability fluctuations become aligned to these via oscillatory entrainment, in order to sharpen and stabilize the stimulus representation. The goal of our study was to examine the global, long time-scale dynamics of entrainment in primary auditory cortex and thalamus in non-human primates performing an intermodal selective attention task. For all subjects, neuroelectric activity was recorded simultaneously using two linear electrode arrays positioned either in corresponding primary auditory cortex (A1) regions of the two hemispheres, or auditory thalamic regions and ipsilateral A1. By analyzing changes in layer-specific neuronal ensemble activity of A1 and simultaneous thalamic activity on the timescale of seconds, we identified a counterphase slow (< 0.1 Hz) fluctuation of two discrete thalamocortical operational modes. One of these was characterized by high amplitude delta-theta frequency band neuronal activity, oscillatory entrainment to the attended stimulus stream, stable response amplitudes and good behavioral performance. The other distinct operational mode was characterized by high amplitude alpha oscillations, generally suppressed, more variable event related responses and poor behavioral performance. We also found that coupling between the amplitude of gamma oscillations and the phase of lower, alpha vs. delta-theta band oscillatory activity followed the same counterphase dynamics, resulting in alpha vs. delta-theta patterning of high frequency neuronal ensemble activity and neuronal firing respectively. We propose that the slow counterphase modulation of oscillatory dynamics in thalamocortical networks reflects intermittent dominance of “task positive” and “task negative” large-scale functional networks in regulating and utilizing information processing resources.

Talk 3: Multiplexed cross-frequency information transfer during continuous speech perception

Hyojin Park1, Gregor Thut1, Joachim Gross1; 1Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom

Comprehension of coherent speech entails neural representation from early perceptual processing to higher cognitive functions as a network. Cortical oscillations are promising tools to study this network considering their inherent spectrotemporal characteristics. We previously found that segmentation and coding of speech relies on a nested hierarchy of entrained cortical oscillations. Speech entrains the phase of delta and theta and the amplitude of gamma oscillations in the auditory cortex. Importantly, phase entrainment is stronger in the right auditory cortex and amplitude entrainment is stronger in the left auditory cortex. Based on this asymmetry, we further investigated top-down directional information transfer on left and right auditory cortices (LAC and RAC) using transfer entropy. MEG data from 22 participants was obtained during passive listening to a 7-minute real-life story (intelligible speech) and the same story played backward (unintelligible speech). We performed transfer entropy analysis within and between the relevant frequency bands (delta, theta, gamma) and identified cortical regions of information transfer that was significantly stronger in intelligible than unintelligible speech. Our results revealed that delta phase in the left inferior frontal gyri including BA44/45/47 regions and right temporal regions modulated delta phase in LAC. Interestingly, the left hemisphere delta phase results match information transfer from gamma to delta phase in LAC, and the right hemisphere delta phase results match information transfer from theta to delta phase in LAC. This suggests that multiplexed directed interactions between entrained brain oscillations across cortical areas could be an important mechanism for cortical processing of continuous speech streams.

Talk 4: How coupled alpha and gamma oscillations might serve to allocate attention

Ole Jensen1, Eelke Spaak1, Bart Gips1, Til Ole Bergmann1, Mathilde Bonnefond1; 1Donders Centre for Cognitive Neuroimaging, Radboud University, The Netherlands

In our daily lives we are bombarded with sensory input. Thus networks in the brain must rely on powerful mechanism for limiting and prioritizing the input flow in order to prevent information overload. In the rat hippocampus, it is well established that neurons representing different spatial representations fire at different phases of the theta cycle. This mechanism limits the information presented by producing sweeps of spatial representations organized according to excitability. Similarly, we hypothesize that alpha oscillations provide a mechanism for ordering visual input according to ‘relevance’. This alpha band activity is under top-down control. Gamma oscillations phase-locked to the alpha oscillations serve to keep competing representations apart in time. Further, neuronal synchronization in the gamma band provides a strong feed forward drive. As a result sweeps representing short 'to‐do‐lists' organized as a temporal phase code is produced in every alpha cycle. Empirical support for such a mechanism will be discussed. These studies are based on MEG in humans performing various kinds of cross-model, memory and spatial attention task. Further empirical support includes findings in non-human primates. Finally predictions and future work required for testing the framework will be discussed.


Mini-Symposium Session 9

Tuesday, March 31, 10:00 am - Noon, Grand Ballroom B/C

Fresh perspectives on social perception: From functional specialization to connectivity

Chair: Emily S. Cross, Radboud University Nijmegen, Bangor University
Speakers: Kami Koldewyn, Emily S. Cross, Zeynep Saygin

Over the past decade, a growing interest in the neurobiological foundations of how we perceive and interact with others has emerged. While the idea of a “social brain” is not new (c.f., Brothers, 1990), the past several years have seen ever-increasing neuroimaging studies seeking to map the neural correlates of myriad social perceptual processes, ranging from how we perceive bodies or faces to how we make sense of others’ actions and social interactions. This minisymposium highlights three novel findings in this domain, each stemming from a distinct methodological approach. Kami Koldewyn introduces the discovery of a portion of the superior temporal sulcus specialized for perceiving dynamic social interactions. This region was identified with targeted functional localization scans, which confirm this region to be distinct from nearby brain areas sensitive to other social perceptual cues, including biological motion, faces, and bodies. Emily Cross highlights how effective connectivity approaches, such as dynamic causal modeling, offer new ways to test models of social action perception. Her work uses DCM to evaluate a predictive coding model of action observation and demonstrates how familiarity alters effective connectivity between sensorimotor cortical regions. Finally, Zeynep Saygin uses structural connectivity and resting-state functional connectivity to explore functional specialization for several social perceptual features, including faces, bodies, and theory of mind. Her data provide converging evidence for a tight link between functional and anatomical connectivity and function. Together, the presentations emphasize how different methodological approaches can complement each other and together fuel novel discoveries in the social perception domain.

Talk 1: Is a region in the Posterior Superior Temporal Sulcus (pSTS) selectively engaged in the perception of social interactions?

Kami Koldewyn1, Sarah Weigelt2, Kilian Semmelmann2, Nancy Kanwisher3; 1School of Psychology, Bangor University, 2Fakultät für Psychologie, Ruhr-Universität Bochum, 3Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology

Successful social behavior requires the ability to perceive not just individuals and their behavior, but pairs of people and the interactions between them. Social interactions are multifacted, subtle, and important. We can quickly discern if two people are cooperating or competing, flirting or fighting, and helping or hindering. The brain basis of this remarkable ability has remained largely unexplored. Here, using fMRI, we show that a region in the superior temporal sulcus, identifiable in the majority of subjects individually with a short functional localizer scan, responds about twice as strongly when viewing pairs of people interacting with each other compared to pairs of people acting independently. This selective response to seeing social interactions is unlikely to be accounted for in terms of simple perceptual features because the same region responds more to interactions than independent actions whether the agents are people depicted in video clips, people in point-light displays, or simple animated shapes. This functional response is nearby but both distinct from, and not explainable by, previously reported cortical responses to biological motion, faces, and other people’s thoughts. Although the precise computations conducted and representations extracted in this region remain to be discovered, our evidence points to a specialized role of this region in the perception of dynamic social interactions.

Talk 2: The modulation of sensorimotor connectivity by familiarity during action observation

Emily S. Cross1,2, Thomas Gardner2; 1Behavioural Science Institute; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 2School of Psychology, Bangor University

Watching another person’s actions engages a network of sensorimotor brain regions collectively termed the action observation network (AON). Previous research suggests the AON is more active when watching familiar compared to unfamiliar actions. More recent evidence suggests the relationship between AON engagement and action familiarity is not as straightforward as previously thought, leading to a re-examination of how an observer’s prior action experience shapes perception of others in motion. We examined how observed movement familiarity modulates connections between sensorimotor brain regions using dynamic causal modeling (DCM), a type of effective connectivity analysis. Twenty-one subjects underwent fMRI scanning whilst viewing whole-body movements that varied in terms of their familiarity. Participants’ task was to either predict the next posture the dancer’s body would assume or to respond to a non-action related attentional control question. To assess individuals’ familiarity with each movement, participants rated each video on a measure of visual familiarity outside the scanner. Parametric analyses showed more activity in left middle temporal gyrus, inferior parietal lobule and inferior frontal gyrus as the videos were rated as increasingly familiar. These clusters of activity formed the regions of interest for DCM analyses, which revealed an attenuation of top-down modulation (influence from anterior to posterior nodes of the AON), as well as attenuation in the corresponding reciprocal connection when participants observed videos rated as more familiar. The findings provide support for a predictive coding model of AON function, as well as illuminate how effective connectivity approaches can advance understanding of social action perception.

Talk 3: Connectivity fingerprints for the social brain

Zeynep Saygin1,2, David E. Osher1,3, Kami Koldewyn4, John Gabrieli1, Rebecca Saxe1, Nancy Kanwisher1; 1Brain and Cognitive Sciences, MIT, 2Martinos Center, MGH, 3Department of Psychological and Brain Sciences, Boston University, 4School of Psychology, Bangor University

A fundamental hypothesis in neuroscience is that connectivity mirrors function at a fine spatial grain across the brain. Previous research supports this hypothesis by demonstrating that the degree of voxelwise face-selectivity in the fusiform gyrus of individual subjects can be predicted from that voxel’s connections to the rest of the brain (its unique connectivity fingerprint), measured through diffusion-weighted imaging (DWI). Here we asked whether resting-state functional connectivity (fcMRI) can also predict face-selectivity in the fusiform, whether structural or functional connectivity fingerprints also predict other visual selectivities throughout the brain, and whether connectivity fingerprints exist for higher-level social cognition. We found that both fcMRI and DWI connectivity predicted face selectivity in the fusiform more accurately than did a group analysis of face-selectivity from other subjects. Further, the subset of connections that best predicted face-selectivity were similar between DWI and fcMRI. We performed similar comparisons of DWI and fcMRI connectivity fingerprints for the rest of cortex, for body, object, and scene perception, and for theory-of-mind activation. These data provide converging evidence from both DWI and fcMRI that i) connectivity and function are tightly linked at a voxelwise scale across the whole brain, and ii) functionally-selective voxels can be predicted from either DWI or fcMRI data alone. These results also raise the possibility that connectivity fingerprints direct the functional specialization of cortex in development. Finally, this work provides researchers and clinicians with tools to infer functional brain maps from connectivity alone in individuals who cannot be functionally scanned (e.g., comatose subjects, sleeping infants).