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Saturday, May 17, 2008
Champagne Terrace/Bordeaux (Novotel London West)
10:30 AM
Background:
Converging lines of evidence suggest that the fusiform face area (FFA) may be part of the core pathobiology in autism spectrum disorders (ASD). One criticism of fMRI studies of this region is that the existing evidence is confined to face perception. We have hypothesized that the fusiform may be involved in semantic representations of people, not just perceptual representations of faces.
Objectives:
We sought to determine if the fusiform might automatically activate to implicit representations of people, independent of a perceptual representation of a face.
Methods:
Over five hours of training, 22 typical adults learned to associate unique grayscale “Blobs” with sets of semantic terms that described either social (“friendly, jealous, gentle”) or physical characteristics (“grainy, hollow, damp”). Participants then completed an fMRI task, which involved deciding whether two Blobs on the screen were visually identical, without reference to the learned semantic descriptors.
Results:
Random effects region-of-interest analyses showed significantly greater activity in the left FFA in response to social, relative to physical Blobs (t(22)=3.78, p<.005). Social Blobs also activated regions of the motive circuit involving globus pallidus, amygdala, and cingulate cortex, suggesting that the socially-relevant associations were ingrained and rewarding for visual processing tasks.
Conclusions:
Automatic activation of the fusiform gyrus to abstract visual objects associated with social semantic attributes provides evidence that this part of the ventral visual pathway may be instrumental in linking percepts with cognitive representations. Atypical function in this region could be instrumental in bringing about the primary signs and symptoms of autism. The FFA seems to be involved in person recognition and understanding, independent of its role in perceptual analyses of the face. We suggest that the FFA really might be better referred to as the fusiform person area, to expand its role beyond elementary perceptual processes to semantic representations and social knowledge.
Converging lines of evidence suggest that the fusiform face area (FFA) may be part of the core pathobiology in autism spectrum disorders (ASD). One criticism of fMRI studies of this region is that the existing evidence is confined to face perception. We have hypothesized that the fusiform may be involved in semantic representations of people, not just perceptual representations of faces.
Objectives:
We sought to determine if the fusiform might automatically activate to implicit representations of people, independent of a perceptual representation of a face.
Methods:
Over five hours of training, 22 typical adults learned to associate unique grayscale “Blobs” with sets of semantic terms that described either social (“friendly, jealous, gentle”) or physical characteristics (“grainy, hollow, damp”). Participants then completed an fMRI task, which involved deciding whether two Blobs on the screen were visually identical, without reference to the learned semantic descriptors.
Results:
Random effects region-of-interest analyses showed significantly greater activity in the left FFA in response to social, relative to physical Blobs (t(22)=3.78, p<.005). Social Blobs also activated regions of the motive circuit involving globus pallidus, amygdala, and cingulate cortex, suggesting that the socially-relevant associations were ingrained and rewarding for visual processing tasks.
Conclusions:
Automatic activation of the fusiform gyrus to abstract visual objects associated with social semantic attributes provides evidence that this part of the ventral visual pathway may be instrumental in linking percepts with cognitive representations. Atypical function in this region could be instrumental in bringing about the primary signs and symptoms of autism. The FFA seems to be involved in person recognition and understanding, independent of its role in perceptual analyses of the face. We suggest that the FFA really might be better referred to as the fusiform person area, to expand its role beyond elementary perceptual processes to semantic representations and social knowledge.