Sociality and interaction envelope organize visual action representations.

Area of Science:

• Neuroscience
• Cognitive Science
• Computer Vision

Background:

• The human visual system processes a vast array of observed actions.
• Understanding the organizational principles of the visual cortex for action perception is crucial.

Purpose of the Study:

• To investigate how the visual cortex is organized to represent diverse human actions.
• To identify the key features and large-scale networks involved in visual action processing.

Main Methods:

• Functional neuroimaging (fMRI) was used to measure brain responses.
• Participants viewed short videos of everyday actions.
• Voxel-wise encoding modeling and clustering analyses were applied to probe response structures.

Main Results:

• Visual cortex responses were well explained by feature spaces including body parts and action targets (objects, people, self, space).
• Five large-scale networks were identified, distinguishing social actions and categorizing others by interaction envelope scale.
• Networks ranged from fine-scale object manipulation to large-scale whole-body movements.

Conclusions:

• The visual cortex organizes action representations based on body parts and the scale of interaction.
• These findings suggest major representational divisions in how the brain processes visual action information.