Biology subjects

Orgs, G.

Publications and source records attributed to Orgs, G..

3 recordsLinked to original sources

bioRxiv2023

Top-down biological motion perception does not differ between adults scoring high versus low on autism traits

The perception of biological motion is an important social cognitive ability. Models of biological motion perception recognize two processes that contribute to the perception of biological motion: a bottom-up process that binds optic-flow patterns into a coherent percept of biological motion and a top-down process that binds sequences of body-posture snapshots over time into a fluent percept of biological motion. The vast majority of studies on autism and biological motion perception have used point-light figure stimuli, which elicit biological motion perception predominantly via bottom-up processes. Here, we investigated whether autism is associated with deviances in the top-down processing of biological motion. For this, we tested a sample of adults scoring low vs high on autism traits on a recently validated EEG paradigm in which apparent biological motion is combined with frequency tagging (Cracco et al., 2022) to dissociate between two percepts: 1) the representation of individual body postures, and 2) their temporal integration into movements. In contrast to our hypothesis, we found no evidence for a diminished temporal body posture integration in the high-scoring group. We did, however, find a group difference that suggests that adults scoring high on autism traits have a visual processing style that focuses more on a single percept (i.e. either body postures or movements, contingent on saliency) compared to adults scoring low on autism traits who instead seemed to represent the two percepts included in the paradigm in a more balanced manner. Although unexpected, this finding aligns well with the autism literature on perceptual stability(/rigidity).

neuroscience↗

bioRxiv2022

The Role of Objecthood and Animacy in Apparent Movement Processing

Movement perception involves both motion and form processing. Previous research has shown that processing along the motion pathway requires a familiar but not necessarily a human shape. However, the role of objecthood and animacy in the form pathway is less clear. Here, we used EEG frequency tagging to study how objecthood and animacy influence both posture processing and the integration of postures into movements. Specifically, we measured brain responses to repeating sequences of well-defined or pixelated images (objecthood) of human or corkscrew agents (animacy) performing fluent or non-fluent movements (movement fluency). The results revealed that movement processing was sensitive to objecthood but not to animacy, whereas posture processing was sensitive to both. Thus, our results indicate that movement processing in the form pathway requires a familiar shape, but not necessarily a human shape. Instead, stimulus animacy appears to be relevant only for posture processing.

neuroscience↗

bioRxiv2020

EEG frequency tagging reveals neural entrainment to people moving in synchrony

Humans and other animals have evolved to act in groups, but how does the brain distinguish multiple people moving in group from multiple people moving independently? Across three experiments, we test whether biological motion perception depends on the spatiotemporal relationships among people moving together. In Experiment 1, we apply EEG frequency tagging to apparent biological motion and show that fluently ordered sequences of body postures drive brain activity at three hierarchical levels of biological motion processing: image, body sequence, and movement. We then show that movement-, but not body- or image-related brain responses are enhanced when observing four agents moving in synchrony. Neural entrainment was strongest for fluently moving synchronous groups (Experiment 2), displayed in upright orientation (Experiment 3). Our findings show that the brain preferentially entrains to the collective movement of human agents, deploying perceptual organization principles of synchrony and common fate for the purpose of social perception.

neuroscience↗