Biology subjects

Szinte, M.

Publications and source records attributed to Szinte, M..

10 recordsLinked to original sources

bioRxiv2026

Optimizing MR-based gaze-decoding for eyes-closed eye-tracking in fMRI

Eye movements provide valuable insights into human cognition and are a critical variable in numerous functional magnetic resonance imaging (fMRI) studies. Yet, when the eyes are closed, camera-based eye-tracking is unavailable, making studies of eyes-closed states challenging. Here, we address this gap using DeepMReye, a deep learning framework for camera-free gaze reconstruction from the MR-signal of the eyes. We first show that fine-tuning DeepMReye on visuomotor calibration data acquired with the eyes open significantly improves gaze decoding, and that this fine-tuning does not require simultaneous camera-based data. We next assessed whether decoding could be extended to eyes-closed states using a novel auditory-guided task, in which participants gazed at learned target positions with and without visual input, and with their eyes open, blinking, or closed. While DeepMReye was originally trained exclusively on eyes-open data, the network successfully generalized to eyes-closed periods, and this generalization was further improved through task-specific fine-tuning. Finally, fine-tuning also improved decoding of eyelid-state (open versus closed) directly from the MR-signal. These findings demonstrate that gaze and eyelid-state monitoring during eyes-closed periods is feasible, enabling broader integration of eye-tracking in fMRI research.

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bioRxiv2026

Eye-Tracking-BIDS: the Brain Imaging Data Structure extended to gaze position and pupil data

The Brain Imaging Data Structure (BIDS) is a widely adopted, community-driven standard to organize neuroimaging data and metadata. Although numerous extensions have been developed to incrementally extend coverage to new modalities and data types, an unambiguous, granular specification for eye-tracking recordings is lacking. Here, we present how BIDS will structure data and metadata produced by eye-tracking devices, including gaze position and pupil data. In addition to prescribing the organization of the unprocessed (raw) recordings and associated metadata as produced by the device, BEP20 also resolves gaps in current BIDS specifications beyond the scope of eye tracking. In particular, it adds a mechanism for including asynchronous model parameters and messages, such as contextual information, statuses, and events, such as triggers, generated by the device. BEP20 includes examples that illustrate its applicability in various experimental settings. This BIDS extension provides a robust standard that supports the development of self-adaptive, open, and automated eye-tracking data structures, thereby bolstering transparency and reliability of results in this field.

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bioRxiv2024

A retinotopic reference frame for space throughout human visual cortex

We perceive the world as stable despite our rapid eye movements. To explain our sense of visual stability, it has been suggested that the brain encodes the location of attended visual stimuli in an external, or spatiotopic, reference frame. However, such spatiotopy is seemingly at odds with the fundamental retinotopic organization of visual inputs. Here, we probe the spatial reference frame of vision using ultra-high-field (7T) fMRI and voxel-level receptive field modeling, while manipulating both gaze direction and spatial attention. To manipulate spatial attention, participants performed an equally demanding visual task on either a bar stimulus that traversed the visual field, or a small stimulus at fixation. To dissociate retinal stimulus position from its real-world position the entire stimulus array was placed at one of three distinct horizontal screen positions in each run. We found that population receptive fields in all cortical visual field maps are pinioned to the retina, irrespective of how spatial attention is deployed. This pattern of results is strong evidence for a fully retinotopic reference frame for visual-spatial processing. Reasoning that a spatiotopic reference frame could independently be computed at the population level of entire visual areas rather than in individual voxels, we additionally used Bayesian decoding of stimulus location from the BOLD response patterns in visual areas. We found that decoded stimulus locations also adhere to the retinotopic frame of reference. Again, this result holds for all visual areas and irrespective of the deployment of spatial attention. Our findings reorient the search for visual stability mechanisms toward transient sensorimotor interactions rather than static spatiotopic maps.

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bioRxiv2023

Mammals achieve common neural coverage of visual scenes using distinct sampling behaviors

Most vertebrates use head and eye movements to quickly change gaze orientation and sample different portions of the environment with periods of stable fixation. Visual information must be integrated across several fixations to construct a more complete perspective of the visual environment. In concert with this sampling strategy, neurons adapt to unchanging input to conserve energy and ensure that only novel information from each fixation is processed. We demonstrate how adaptation recovery times and saccade properties interact, and thus shape spatiotemporal tradeoffs observed in the motor and visual systems of different species. These tradeoffs predict that in order to achieve similar visual coverage over time, animals with smaller receptive field sizes require faster saccade rates. Indeed, we find comparable sampling of the visual environment by neuronal populations across mammals when integrating measurements of saccadic behavior with receptive field sizes and V1 neuronal density. We propose that these mammals share a common statistically driven strategy of maintaining coverage of their visual environment over time calibrated to their respective visual system characteristics.

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bioRxiv2019

Visual landmarks calibrate auditory space across eye movements

Visual objects that are present both before and after eye movements can act as landmarks, aiding localization of other visual stimuli. We investigated whether visual landmarks would also influence auditory localization - despite participants head position remaining unchanged. Participants made eye-movements from central fixation to a peripheral visual landmark, which either remained stationary or was covertly displaced. Following the movement, participants judged whether a stimulus (auditory or visual) was shifted in location relative to before the movement. Visual localization estimates shifted along with the landmark, although the landmark displacement itself went unnoticed. Interestingly, auditory localization estimates were also displaced. Thus, despite identical auditory input reaching the ears, two auditory stimuli originating from the same position were perceived as spatially distinct when the visual landmark moved. These results are consistent with the idea that auditory spatial information is encoded within an eye-centered reference frame and subject to spatial recalibration by visual landmarks. HighlightsO_LIVisual landmarks affect stimulus localization across eye movements C_LIO_LIWe show this also for auditory stimuli, even when the head remains stable C_LIO_LIDue to a visual landmark displacement, identical auditory stimuli are perceived as shifted C_LIO_LIThis suggests that auditory space is calibrated on eye-centered maps across saccades C_LI

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bioRxiv2019

Sounds are remapped across saccades

To achieve visual space constancy, our brain remaps eye-centered projections of visual objects across saccades. Here, we measured saccade trajectory curvature following the presentation of visual, auditory, and audiovisual distractors in a double-step saccade task to investigate if this stability mechanism also accounts for localized sounds. We found that saccade trajectories systematically curved away from the position at which either a light or a sound was presented, suggesting that both modalities are represented in eye-centered oculomotor centers. Importantly, the same effect was observed when the distractor preceded the execution of the first saccade. These results suggest that oculomotor centers keep track of visual, auditory and audiovisual objects by remapping their eye-centered representations across saccades. Furthermore, they argue for the existence of a supra-modal map which keeps track of multi-sensory object locations across our movements to create an impression of space constancy.

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bioRxiv2019

Stimulus blanking reveals transsaccadic feature transfer

Across saccadic eye movements, the visual system receives two successive static images corresponding to the pre- and the postsaccadic projections of the visual field on the retina. The existence of a mechanism integrating the content of these images is today still a matter of debate. Here, we studied the transfer of a visual feature across saccades using a blanking paradigm. Participants moved their eyes to a peripheral grating and discriminated a change in its orientation occurring during the eye movement. The grating was either constantly on the screen or briefly blanked during and after the saccade. Moreover, it either was of the same luminance as the background (i.e., isoluminant) or anisoluminant with respect to it. We found that for anisoluminant grating, the orientation discrimination across saccade was improved when a blank followed the onset of the eye movement. Such effect was however abolished with isoluminant grating. Additionally, performance was also improved when an anisoluminant grating presented before the saccade was followed by an isoluminant one. These results demonstrate that a detailed representation of the presaccadic image was transferred across saccades allowing participants to perform better on the trans-saccadic orientation task. While such a transfer of visual orientation across saccade is masked in real-life anisoluminant conditions, the use of a blank and of isoluminant postsaccadic grating allowed here to reveal its existence.\n\nSignificance statementStatic objects are perceived as not moving across eye movements despite their visual projection shifts on our retina. To compensate for such shifts and create a continuous perception of space, our brain may keep track of objects visual features across our movements. We found that shortly blanking a contrast-defined object during and after saccades allows to recover a detailed representation of its orientation. We propose that the transfer of visual content across saccades revealed with the use of a simple blank plays an important role in ensuring our continuous and stable perception of the world.

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bioRxiv2018

Pre-saccadic remapping relies on dynamics of spatial attention

Each eye movement shifts the projections of the visual scene on the retina. It has been proposed that the receptive fields of neurons in oculomotor areas are remapped pre-saccadically to account for these shifts. While remapping of the whole visual scene seems prohibitively complex, selection by visual attention may limit these processes to a subset of attended locations. Because attentional selection consumes time, remapping of attended locations should evolve in time, too. In our study, we cued a spatial location by presenting an attention capturing cue at different times before a saccade and constructed detailed maps of attentional allocation across the visual field. We observed no remapping when the cue appeared shortly before saccade. In contrast, when the cue appeared sufficiently early before saccade, attentional resources were reallocated to the remapped location. Our results suggest that pre-saccadic remapping is an attentional process relying on the spatial and temporal dynamics of visual attention.

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bioRxiv2017

Visual attention is not always spatially coupled to subsequent oculomotor program

The premotor theory of attention postulates that spatial attention arises from the activation of saccade areas and that the deployment of attention is the consequence of motor programming. Yet, attentional and oculomotor processes have been shown to be dissociable at the neuronal level in covert attention tasks. To investigate a potential dissociation at the behavioral level, we instructed human participants to saccade towards one of two nearby, competing saccade cues. The spatial distribution of visual attention was determined using oriented Gabor stimuli presented either at the cue locations, between them or at several other equidistant locations. Results demonstrate that accurate saccades towards one of the cues were associated with presaccadic enhancement of visual sensitivity at the respective saccade endpoint compared to the non-saccaded cue location. In contrast, averaging saccades, landing between the two cues, were not associated with attentional facilitation at the saccade endpoint, ruling out an obligatory coupling of attentional deployment to the oculomotor program. Rather, attention before averaging saccades was equally distributed to the two cued locations. Taken together, our results reveal a spatial dissociation of visual attention and saccade programming. They suggest that the oculomotor program depends on the state of attentional selection before saccade onset, and that saccade averaging arises from unresolved attentional selection.

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bioRxiv2017

Spreading pre-saccadic attentional resources without trade-off

When preparing a saccade, attentional resources are focused at the saccade target and its immediate vicinity. Here we show that this does not hold true when saccades are prepared towards a recently extinguished target. We obtained detailed maps of orientation sensitivity when participants prepared a saccade toward a target that either remained on the screen or disappeared before the eyes moved. We found that attention was mainly focused at the immediate surround of the visible target and increasingly spread to more peripheral locations as a function of the delay between the targets disappearance and the saccade. Interestingly, this spread was accompanied by an overall increase in sensitivity, speaking against a dilution of limited resources over a larger spatial area. We hypothesize that these results reflect the behavioral consequences of the spatio-temporal dynamics of visual receptive fields in the presence and in the absence a structured visual cue.

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