Primacy of observed action representation during natural vision
| Main Author: | Samuel A. Nastase |
|---|---|
| Format: | info Proceeding Journal |
| Terbitan: |
, 2017
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/4016416 |
Daftar Isi:
- The received understanding of cortical information processing during, e.g., object recognition, is based on experiments using highly-controlled, often static stimuli. However, dynamic naturalistic stimuli convey considerably richer perceptual and semantic information, and can provide complementary insights. The current line of work uses functional MRI to investigate how the brain extracts behaviorally-relevant semantic information during naturalistic vision to support action recognition. Participants viewed brief video clips of animals behaving in their natural environments. Stimuli were organized in a factorial design with four behavioral categories (eating, fighting, running, and swimming) and five taxonomic categories (birds, insects, primates, reptiles, and ungulates). Replicating existing work, we found that animal taxonomy was represented in ventral temporal cortex, while animal behavior was represented in lateral occipitotemporal, anterior parietal, and premotor cortices. Task demands enhanced representational discriminability along behaviorally relevant dimensions in late-stage sensorimotor cortices. Interestingly, throughout much of cortex, animal behavior accounted for markedly more variance in representational geometry than the animal taxonomy—even in ventral temporal cortex. Furthermore, behavioral category classification generalized across stimuli and taxonomic categories. Ongoing research efforts using a broader range of stimuli depicting social and nonsocial human actions are intended to provide insights into the representational geometry supporting action understanding at various stages of cortical processing. Our findings suggest that dynamic stimulus features, particularly those conveying behaviorally-relevant action information, dominate cortical processing during natural vision.