Neural correlates of executive function in autistic spectrum disorders.
BACKGROUND
Some clinical characteristics of high-functioning individuals with autistic spectrum disorder (ASD) such as repetitive stereotyped behaviors, perseveration, and obsessionality have been related to executive function (EF) deficits, more specifically to deficits in inhibitory control and set shifting and mediating frontostriatal neural pathways. However, to date, no functional imaging study on ASD has investigated inhibition and cognitive flexibility and no one has related EF brain activation to brain structure.


METHODS
We compared brain activation (using functional magnetic resonance imaging) in 10 normal intelligence adults with ASD and 12 healthy control subjects during three different EF tasks: 1) motor-inhibition (GO/NO-GO); 2) cognitive interference-inhibition (spatial STROOP); and 3) set shifting (SWITCH). Using voxel-based morphometry, we investigated if cortical areas which were functionally different in people with ASD were also anatomically abnormal.


RESULTS
Compared with control subjects, ASD individuals showed significantly increased brain activation in 1) left inferior and orbital frontal gyrus (motor-inhibition); 2) left insula (interference-inhibition); and 3) parietal lobes (set shifting). Moreover, in individuals with ASD, increased frontal gray matter density and increased functional activation shared the same anatomical location.


CONCLUSIONS
Our findings suggest an association between successful completion of EF tasks and increased brain activation in people with ASD, which partially may be explained by differences in brain anatomy.
Schmitz
Nicole
N
Department of Psychological Medicine, Section of Brain Maturation, Institute of Psychiatry, King' College London, UK. n.schmitz@lumc.nl
Rubia
Katya
K
Daly
Eileen
E
Smith
Anna
A
Williams
Steve
S
Murphy
Declan G M
DG
D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D003657:Decision Making / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011340:Problem Solving / Q000502:physiology*
D010100:Oxygen