Soc. Neurosci. Abstr. 1997.10


H. Onoe1, M. Kato2*, H. Tsukada3, and I. Fujita2 1Dept.Neurosci., Osaka Bioscience Institute, 2Dept. Cognitive Neurosci., Osaka Univ. Med. Sch., Suita, Osaka 565, Japan; 3Hamamatsu Photonics, PET Center, Hamakita, Shizuoka 434, Japan.

Neurons in the monkey inferior temporal cortex (IT) respond preferentially to complex visual features of objects. Among them are a population of neurons which selectively respond to the sight of faces. Face- responsive neurons have been suggested to be clustered in particular regions of the IT and adjacent cortices within the superior temporal sulcus. In the present study, we applied positron emission tomography (PET) scanning techniques to awake monkeys to determine whether specific regions of the IT are active during presentation of visual images of faces to the monkeys.
A set of pictures of monkey faces or a set of other 2-D geometrical figures (GFs) were sequentially presented to monkeys (Macaca mulatta) which were fixating on a spot on a CRT display. Activated brain regions were examined by regional cerebral blood flow measurement using 15O-labeled water, and were analyzed by the statistical parametric mapping (SPM) method.
Significantly stronger activation was produced by either faces or GFs than by the fixation spot in a series of cortices (striate and prestriate cortices as well as areas TEO and TE in the IT) along the ventral visual pathway. Although the regions activated by faces and those activated by GFs overlapped extensively, discrete regions in the most posterior/dorsal part and an anterior part of area TE were activated by faces, but not by GFs. These findings suggest that subregions in area TE are specifically involved in visual information processing of faces.(Supported by CREST.)