Spatial and Temporal Distribution of Face and Object Representations in the Human Brain

Functional brain imaging has revealed that the functional architecture of ventral object vision pathway has a macroscopic organization. This architecture is characterized most commonly in terms of regions that demonstrate category-related response preferences, most notably the fusiform face area, which responds maximally during face perception, and the parahippocampal place area, which responds maximally to scenes and buildings. The representation of faces and object categories, however, extends beyond the boundaries of these regions that are defined by the stimuli that elicit maximal responses. Faces and other object categories evoke distinct patterns of response across expanses of ventral temporal cortex that include cortex that responds submaximally to the category being viewed. Thus, representations of faces are distributed locally within ventral temporal cortex. The representation of faces and objects also is distributed across other cortical areas. A second, locally distributed representation of faces and objects exists in lateral temporal cortex. Whereas the representation in ventral temporal cortex appears to contain information about the appearance of object form, the representation in lateral temporal cortex appears to contain information about how faces, bodies, and objects move. Neural responses to faces are also distributed across time. The early and late parts of responses to faces and objects show different effects of memory and attention and may reflect a differentiation between early feed-forward processing and later processing with stronger effects of interregional interactions. Thus, the neural representations of faces and objects appear to be distributed in time as well as in space.