fMRI investigation of working memory for faces in autism: visual coding and underconnectivity with frontal areas.
Brain activation and functional connectivity were investigated in high functioning autism using functional magnetic resonance imaging in an n-back working memory task involving photographic face stimuli. The autism group showed reliably lower activation compared with controls in the inferior left prefrontal area (involved in verbal processing and working memory maintenance) and the right posterior temporal area (associated with theory of mind processing). The participants with autism also showed activation in a somewhat different location in the fusiform area than the control participants. These results suggest that the neural circuitry of the brain for face processing in autism may be analyzing the features of the face more as objects and less in terms of their human significance. The functional connectivity results revealed that the abnormal fusiform activation was embedded in a larger context of smaller and less synchronized networks, particularly indicating lower functional connectivity with frontal areas. In contrast to the underconnectivity with frontal areas, the autism group showed no underconnectivity among posterior cortical regions. These results extend previous findings of abnormal face perception in autism by demonstrating that the abnormalities are embedded in an abnormal cortical network that manages to perform the working memory task proficiently, using a visually oriented, asocial processing style that minimizes reliance on prefrontal areas.
Koshino
Hideya
H
Department of Psychology, California State University, San Bernardino, CA 92407, USA.
Kana
Rajesh K
RK
Keller
Timothy A
TA
Cherkassky
Vladimir L
VL
Minshew
Nancy J
NJ
Just
Marcel Adam
MA
D000328:Adult; D001321:Autistic Disorder / Q000503:physiopathology*; D001931:Brain Mapping; D005071:Evoked Potentials; D005145:Face; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology*; D010364:Pattern Recognition, Visual; D014793:Visual Cortex / Q000503:physiopathology*