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Abstract:
In my lab we use functional magnetic resonance imaging (fMRI)
to watch the neural machinery of vision in action as people carry
out various visual tasks. I will describe work we have done
characterizing two functionally distinct regions of human visual
cortex in detail. The "fusiform face area" is a cortical region
that responds strongly and selectively when people view images of
faces, but only weakly when they view images of other kinds of
things. The "parahippocampal place area" responds whenever
participants view images of places (i.e. indoor or outdoor scenes),
but weakly when they view faces or objects. The high degree of
selectivity exhibited by these areas suggests that the perceptual
analysis of different object classes may be carried out by a set of
distinct mechanisms, each tuned for different types of stimuli. I
will describe some of our recent work demonstrating that the face
and place areas are involved not only in visual perception, but
also visual cognition; the activity in these cortical regions can
be modulated by visual attention, correlated with perceptual
awareness (with the stimulus held constant), influenced by
high-level perceptual inferences, and even activated by simply
imaging a face or place with eyes closed when no stimulus is
present at all.
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