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Experience-dependent modulation of category-related cortical activity
Linda L Chao1, Jill Weisberg, Alex Martin
1Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA. llchao@itsa.ucsf.edu
Cerebral Cortex (New York, N.Y. : 1991)
|April 16, 2002
Summary
Object naming activates specific brain regions, but familiarity reduces this activity across widespread areas. This suggests overlapping object representations in the brain, not discrete category-specific zones.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neuroimaging
Background:
- Object naming activates distinct brain regions, but these areas often respond to multiple categories.
- The precise nature of category representation in the brain remains incompletely understood.
Purpose of the Study:
- To investigate how stimulus familiarity influences category-specific brain activity during object naming.
- To explore whether object representations are localized or distributed in the ventral occipito-temporal cortex.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used to monitor brain activity.
- Participants named pictures of objects from different categories (animals, tools).
- Stimulus familiarity (novel vs. familiar) was manipulated to assess its effect on neural responses.
Main Results:
- Naming familiar objects elicited reduced activation compared to novel objects across object-responsive areas in the ventral occipito-temporal cortex.
- This reduction in activation was independent of the initially maximal category response.
- Experience-dependent reductions in activity were category-specific in regions like the lateral temporal and left premotor cortices.
Conclusions:
- Object representations in the ventral occipito-temporal cortex are widespread and overlapping, rather than confined to discrete category-specific areas.
- Category-related brain activations likely reflect the retrieval of category-specific features and attributes, influenced by experience.