Patchy organization and asymmetric distribution of the neural correlates of face processing in monkey inferotemporal cortex.
BACKGROUND
It is believed that a face-specific system exists within the primate ventral visual pathway that is separate from a domain-general nonface object coding system. In addition, it is believed that hemispheric asymmetry, which was long held to be a distinct feature of the human brain, can be found in the brains of other primates as well. We show here for the first time by way of a functional imaging technique that face- and object-selective neurons form spatially distinct clusters at the cellular level in monkey inferotemporal cortex. We have used a novel functional mapping technique that simultaneously generates two separate activity profiles by exploiting the differential time course of zif268 mRNA and protein expression.


RESULTS
We show that neurons activated by face stimulation can be visualized at cellular resolution and distinguished from those activated by nonface complex objects. Our dual-activity maps of face and object selectivity show that face-selective patches of various sizes (mean, 22.30 mm2; std, 32.76 mm2) exist throughout the IT cortex in the context of a large expanse of cortical territory that is responsive to visual objects.


CONCLUSIONS
These results add to recent findings that face-selective patches of various sizes exist throughout area IT and provide the first direct anatomical evidence at cellular resolution for a hemispheric asymmetry in favor of the right hemisphere. Together, our results support the notion that human and monkey brains share a similarity in both anatomical organization and distribution of function with respect to high-level visual processing.
Zangenehpour
Shahin
S
Department of Psychology, McGill University, Montreal, Quebec, Canada. shahin.zangenehpour@mcgill.ca
Chaudhuri
Avi
A
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D002522:Chlorocebus aethiops / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D051766:Early Growth Response Protein 1; D005145:Face; D007839:Functional Laterality / Q000502:physiology*; D006652:Histological Techniques; D017874:Immediate-Early Proteins / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000378:metabolism; D010775:Photic Stimulation; D012333:RNA, Messenger / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014741:Video Recording; D014796:Visual Perception / Q000502:physiology*
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors