Disentangling Representations of Object Shape and Object Category in Human Visual Cortex: The Animate-Inanimate...

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• The human occipitotemporal cortex shows distinct functional magnetic resonance imaging (fMRI) activity patterns for different object categories, notably animate versus inanimate objects.
• It remains debated whether these distinctions arise from category-specific visual properties or from genuine object categorization.

Purpose of the Study:

• To investigate whether the animate-inanimate distinction in neural representations is driven by visual features or object category.
• To disentangle the contributions of visual properties and semantic category to brain activity patterns.

Main Methods:

• fMRI was used to measure brain responses to animate and inanimate objects carefully matched for shape and low-level visual features.
• Representational Similarity Analysis (RSA) was employed to compare neural dissimilarity with visual and categorical dissimilarity.
• Visual dissimilarity was quantified through visual search experiments measuring outline and texture differences.

Main Results:

• Animate- and inanimate-preferring regions were identified in the temporal cortex, even with matched object pairs.
• Visual dissimilarity (overall, outline, texture) predicted neural dissimilarity in visual cortex.
• Several brain regions showed categorical dissimilarity predicting neural dissimilarity after controlling for visual dissimilarity.

Conclusions:

• The animate-inanimate organization in the visual cortex is not fully explained by visual properties like shape or texture.
• Representations of visual object properties and object category likely coexist in anterior visual system regions.