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Cortical mechanisms for transsaccadic perception and memory

Symposium Session 9: Tuesday, April 16, 2024, 1:30 – 3:30 pm EDT, Ballroom East

Chairs: John Douglas Crawford1, Bianca Baltaretu2; 1York University, Toronto Canada, 2Justus Liebig University Giessen, Germany
Presenters: Marisa Carrasco, Nina Hanning, Antonio Fernández, A. Caglar Tas, Jessica Parker, Aaron Buss, Julie Golomb, Bianca Baltaretu, John Douglas Crawford

Visual perception and memory are usually studied in the laboratory with the eyes fixed on one location, but in real world circumstances we make saccades several times per second. Thus, ‘transsaccadic’ perception and memory is the normal state of the visual system. Although saccades help us to place the fovea (and corresponding expanded cortical regions) on objects of interest, they also briefly disrupt vision and then alter the spatial register between eye-fixed memory signals and the external world. Therefore, transsaccadic vision requires additional mechanisms (such as matching remembered and new retinal information) that are not evident when the eyes fixate. In the current symposium, we will highlight recent psychophysical, computational, and neuroimaging approaches to human transsaccadic vision, including 1) the specific roles of early visual cortex and human frontal eye fields in presaccadic attention, 2) the relationship between transsaccadic memory and traditional concepts of visual working memory, 3) mechanisms for remapping visual information across saccades, and 4) cortical mechanisms for transsaccadic perception of specific object features. An emerging theme of this symposium is that although transsaccadic vision recruits specific cortical mechanisms, it engages the entire cortical networks for saccades, vision, and visual memory, as well as other cognitive / sensorimotor systems, to optimize behavior for real world conditions.


Dissociable roles of human frontal eye fields and early visual cortex in presaccadic and covert attention

Marisa Carrasco1, Nina Hanning1,2, Antonio Fernández1; 1New York University, NY, 2Humboldt University, Berlin

Attention is a central neural process that enables selective and efficient processing of visual information. People can attend to specific information either overtly, by making an eye movement to an object of interest, or covertly, without moving their eyes. First, I will highlight some behavioral, neurophysiological, and computational evidence of presaccadic attentional modulations that occur while preparing saccadic eye movements and their differences from those of covert spatial endogenous (voluntary) and exogenous (involuntary) attention (Li, Hanning & Carrasco, TINS 2021). Then, I will present recent transcranial magnetic stimulation (TMS) studies revealing the dissociable roles of early visual cortex (V1/V2) and human frontal eye fields (rFEF+) in presaccadic attention (Hanning, Fernández & Carrasco, Nature Comm, 2023) and endogenous covert attention (Fernández, Hanning & Carrasco, PNAS, 2023). Our findings indicate that presaccadic and endogenous attention modulate perception through cortico-cortical feedback –but with different temporal dynamics– and further dissociate presaccadic and covert spatial attention.

The relationship between transsaccadic visual stability and visual working memory: an fNIRS study

A. Caglar Tas1, Jessica Parker1, Aaron Buss1; 1University of Tennessee, Knoxville, USA

Transsaccadic visual stability (VS) is the process by which the visual system creates a continuous representation of the visual world across saccades. It has been suggested that visual working memory (VWM) plays a direct role in VS by automatically encoding and updating the saccade target properties (Aagten-Murphy & Bays, 2019; van der Stigchel & Hollingworth, 2018). The present study investigates neural signatures of VS, and the possible role of VWM in VS. We recorded neural data using functional near-infrared spectroscopy (fNIRS) while participants completed a VS task (blanking task) and a VWM task (color change detection, CD) separately. In the blanking task, participants were asked to report which direction the saccade target was displaced. On some trials, VS was manipulated by briefly removing the saccade target from the screen (blank). On the others, VS was not disrupted (no-blank). Behaviorally, we found a significant correlation between the blanking and CD tasks: Participants with a higher VWM capacity performed better in the blanking task. Neurally, we found that left inferior parietal cortex was more strongly activated for no-blank than blank trials, suggesting this region is involved in establishing visual stability. In comparison, superior parietal cortex showed increased activation as VWM load increased from 2 to 4 items during the CD task. Importantly, there was a significant positive association between activation in this region during blank trials and performance in the CD task, suggesting a significant link between VWM and the processes by which the visual system establishes VS.

Understanding remapping and its consequences for perception

Julie Golomb1; 1The Ohio State University, USA

Remapping is the updating process that helps align visual input from before and after a saccade. Initial work on remapping focused on anticipatory, presaccadic shifts of neuronal spatial receptive fields, but over time, it has become clear that there are multiple forms of remapping that may operate at different timescales and be mediated by different neural mechanisms. Moreover, there is evidence that remapping may not always be efficient, and the consequences of this can extend to non-spatial processing, resulting in distorted visual feature perception, object binding errors, and disruption of working memory filters following saccades. In this talk I will share recent behavioral and neuroimaging work revealing some of these consequences of saccades and imperfect updating, along with efforts to determine whether factors such as dynamic saccade context and reward/motivation can mitigate these consequences and improve perceptual stability across saccades.

Cortical mechanisms for transsaccadic perception of low-level object features

Bianca Baltaretu1, John Douglas Crawford2; 1Justus Liebig University Giessen, Germany, 2York University, Toronto, Canada

Spatial updating of a single point target has been studied for many years, but the cortical underpinnings for transsaccadic memory and perception of specific object features has received less attention. For example, some studies point to the role of posterior parietal cortex in the transsaccadic updating of a low-level object feature, such as orientation (Dunkley et al., Cortex, 2016), but it is unknown whether parietal cortex plays a general role in transsaccadic perception or if multiple, feature-specific mechanisms are involved. To address this question, we used functional magnetic resonance imaging (fMRI) to test for the cortical correlates of 1) transsaccadic perception of orientation for grasping (Baltaretu et al., J. Neurosci., 2020), 2) a different low-level object feature (i.e., spatial frequency; Baltaretu et al., Sci. Rep., 2021), and 3) multiple object features (i.e., orientation and shape; Baltaretu et al., Sci. Rep., 2023). Our findings, suggest that different occipital and parietal areas are recruited for transsaccadic vision, depending on the nature of the stimulus features, and that these areas become associated with different functional networks, depend on the nature of the task for perception and / or action.







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April 13–16  |  2024