Biology subjects

Huber-Huber, C.

Publications and source records attributed to Huber-Huber, C..

5 recordsLinked to original sources

bioRxiv2026

Visual consequences of saccades explain early cortical response dynamics during natural vision

During natural vision, each saccadic eye movement evokes a large cortical potential known as the lambda response. Traditionally, lambda responses have been considered feedforward responses to new visual input arriving at fixation. In contrast, here we show that they are best explained by the retinal shifts induced by the saccade itself. We first recorded EEG data for thousands of saccades during free viewing of natural scenes and then replayed the same retinal image shifts on a high-speed display during fixation. Temporal response dynamics were virtually identical for real saccades and replayed motion, and most strongly aligned to saccadic peak velocity. A computational model based only on saccade trajectories, 1/f natural-scene statistics, and known human spatiotemporal sensitivity parsimoniously reproduced these dynamics. Our results show that saccade intervals should not be viewed as a gap in visual processing, but as a structured sensory event that shapes human cortical activity during natural viewing.

neuroscience↗

bioRxiv2025

Active vision modulates early cortical stages of visual processing: Evidence from MEG and eye-tracking

It has been hypothesized that the visual system anticipates upcoming visual input contingent on the execution of saccadic eye movements. In line with this idea, it has been shown that changes in visual input across saccades elicit stronger post-saccadic fixation-locked neural responses compared to no-change conditions; an effect known as the preview effect. In the present study, we demonstrate that this preview effect depends on active vision and cannot be explained by either classical or spatiotopic adaptation. In a gaze-contingent experiment, in which participants were cued to make saccades to object stimuli, we concurrently recorded magnetoencephalography (MEG) and eye-tracking data. The source-localized MEG signal was deconvolved with stimulus onset and eye movement events in order to account for systematic variation in gaze behavior related to the no-change (valid preview) and change (invalid preview) conditions. Crucially, preview effects in the primary visual and in ventral-occipital cortices were markedly larger when participants made saccades compared to replay blocks in which we simulated the visual consequences of saccades absent saccade execution, demonstrating that the preview effect cannot be simply explained by classic adaptation. A further control condition ruled out spatiotopic adaptation. Our results show that early visual cortical areas which are not known to exhibit saccadic remapping neurons still show signs of sequential neural history effects across saccades. Previous research might have overlooked this influence of active vision because of the lack of an invalid preview condition which breaks the correspondence between pre-saccadic extrafoveal and post-saccadic foveal stimulation.

neuroscience↗

bioRxiv2025

Narrative Context Shifts Gaze from Visual to Semantic Salience

Humans make over a hundred thousand eye movements daily to gather visual information. But what determines where we look? Current computational models typically link gaze behaviour to visual features of isolated images, but we know that eye movements are also strongly shaped by cognitive goals: Observers gather information that helps them to understand, rather than just represent, the world. Within this framework, observers should focus more on information that updates ones understanding of the environment, and less on what is purely visually salient. Here we tested this hypothesis using a free-viewing paradigm of narratives where we experimentally manipulated the meaningfulness of temporal context by either presenting pictures in a coherent, i.e. correct, order, or in a temporally shuffled order. We developed a novel approach to quantify which visual information is semantically salient (i.e., important for understanding): we separately obtained language narratives for images in stories, and computed the contextual surprisal of visual objects using a large language model. The ability of this semantic saliency model in explaining gaze behaviour was compared to a state-of-the art model of visual saliency (DeepGaze-II). We found that individuals looked relatively more often and more quickly at semantically salient objects when images were presented in coherent compared to shuffled order. In contrast, visual salience did not better account for gaze behaviour in coherent than shuffled order. These findings highlight how internal contextual models guide visual sampling and demonstrate that language models could offer a powerful tool for capturing gaze behavior in richer, meaningful settings.

neuroscience↗

bioRxiv2022

Statistical learning is not error-driven

Prediction errors have a prominent role in many forms of learning. For example, in reinforcement learning, agents learn by updating the association between states and outcomes as a function of the prediction error elicited by the event. One paradigm often used to study error-driven learning is blocking. In forward blocking, participants are first presented with stimulus A, followed by outcome X (A[->]X). In the second phase, A and B are presented together, followed by X (AB[->]X). Here, A[->]X blocks the formation of B[->]X, given that X is already fully predicted by A. In backward blocking, the order of phases is reversed. Here, the association between B and X that is formed during the first learning phase of AB[->]X is weakened when participants learn exclusively A[->]X in the second phase. The present study asked the question whether forward and backward blocking occur during visual statistical learning, the largely automatic and incidental learning of the statistical structure of the environment. In a series of studies, using both forward and backward blocking, we observed robust statistical learning of temporal associations among pairs of images. While we found no compelling evidence for forward blocking, we observed reliable backward blocking in visual statistical learning.

neuroscience↗

bioRxiv2018

Previewing a face in the periphery reduces the fN170: Combined EEG and eye-tracking suggests two stages of trans-saccadic predictive processes

The world appears stable despite saccadic eye-movements. One possible explanation for this phenomenon is that the visual system predicts upcoming input across saccadic eye-movements, based on peripheral preview of the saccadic target. We tested this idea using concurrent electroencephalography (EEG) and eye-tracking. Participants made cued saccades to peripheral upright or inverted face stimuli that could change (invalid preview) or keep their orientation (valid preview) across the saccade. Experiment 1 demonstrated better discrimination performance and a reduced fixation-locked N170 (fN170) with valid than with invalid preview demonstrating integration of pre- and post-saccadic information. Moreover, the early fixation-locked EEG showed a preview face inversion effect suggesting that we perceive pre-saccadic input up to about 170 ms post fixation-onset, at least for face orientation. Experiment 2 replicated Experiment 1 and manipulated the proportion of valid and invalid trials (mostly valid versus mostly invalid, 66.6% to 33.3%) to test whether the preview effect reflected active expectations. A whole-scalp Bayes factor analysis provided evidence for no influence of proportion on the fN170 preview effect. Instead, before the saccade the preview face orientation effect declined earlier in the mostly invalid than in the mostly valid block suggesting some form of pre-saccadic expectations. We conclude that visual stability is achieved by two trans-saccadic integration processes: pre-saccadic prediction, reflected in the pre-saccadic proportion modulation, and early post-saccadic change-detection reflected in the fN170 preview effect.

neuroscience↗