FBS Colloquia No.289Cognitive Neuroscience Group

Another visual pathway: mechanisms underlying rapid processing of facial expression

Facial expression plays an important role in social life of primates including humans. This information is processed along two visual pathways and meets at the amygdala. One pathway is the ventral cortical pathway, and the other is the subcortical pathway. The ventral cortical pathway consists of a series of cortical regions – one part of the most developed regions in the primates brain. The subcortical pathway consists of a fewer stages of phylogenetically ancient regions – superior colliculus, pulvinar, and amygdala. The ventral cortical pathway processes information slowly but accurately, whereas the subcortical pathway rapidly but coarsely. However, the existence of the subcortical pathway has been a focus of hot debates. In this colloquium, I discuss the anatomical and electrophysiological evidence for the subcortical pathway that were recently obtained in the Fujita laboratory. I further discuss my own CNN model analysis of the subcortical pathway. I will demonstrate that the coarse processing is derived from three characteristics of the subcortical pathway, i.e., shallowness of processing stages, receptive field organization, and extent of spatial pooling.