Stimulus inversion and the responses of face and object-sensitive cortical areas

BEHAVIORAL and neuropsychological studies suggest that upright and inverted face stimuli are processed by computationally and anatomically distinct systems. Specifically, inverted faces seem to be addressed by general object perception systems, avoiding face-specific processes. We tested this model by examining the fMRI signal response of a functionally defined fusiform face area and bilateral object-responsive cortical areas during the perception of upright and inverted stimuli (faces and cars). While inversion of face stimuli had no effect upon the magnitude of responses in the fusiform face area, inverted faces evoked greater neural responses compared to upright faces within object regions. This finding supports the assertion that object areas are involved to a greater degree in the perception of inverted vs upright faces. (C) 1999 Lippincott Williams & Wilkins.