Clinicometabolic dissociation of cognitive functions and social behavior in frontal lobe lesions.
OBJECTIVE
Case studies suggest a dissociation between cognitive functions that have been impaired after damage to the dorsolateral prefrontal cortex and social skills disturbed when the ventromedial prefrontal areas are affected. Because this dissociation had not been confirmed in a clinical setting, clinicometabolic correlations were sought in 13 patients with various lesions of the prefrontal cortex.


METHODS
The clinical assessment included extensive testing of executive functions and evaluation of behavioral abnormalities based on an informant questionnaire. Regional cerebral glucose metabolism (rCMRGlu) was measured with [l8F] fluorodeoxyglucose ([18F] FDG) and 31-slide high-resolution PET.


RESULTS
Executive-function test performance was significantly correlated with rCMRGlu in the dorsolateral prefrontal cortex (Brodmann's areas 8, 9, 45, 46, and 47) and anterior cingulate cortex (Brodmann's areas 24 and 32). Behavioral scores were significantly correlated with rCMRGlu in the frontopolar (Brodmann's area 10) and orbitofrontal cortex (Brodmann's areas 11, 12, 13, and 14).


CONCLUSIONS
These results show that impaired executive functions and serial skill deficits are associated with distinct metabolic patterns in patients with frontal lobe pathology. In agreement with activation studies in normal subjects, our data suggest the existence of a modular organization of the frontal cortex in humans, as previously reported in nonhuman primates.
Service Hospitalier Frédéric Joliot, CEA, Orsay, France.
M
M
Sarazin
B
B
Pillon
P
P
Giannakopoulos
G
G
Rancurel
Y
Y
Samson
B
B
Dubois
D000328:Adult; D000368:Aged; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000378:metabolism*; D003287:Contrast Media; D003847:Deoxyglucose / Q000031:analogs & derivatives; D006801:Humans; D001523:Mental Disorders / Q000000981:diagnostic imaging / Q000378:metabolism*; D008609:Mental Status Schedule; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000293:injuries* / Q000378:metabolism* / Q000503:physiopathology; D012919:Social Behavior; D014055:Tomography, Emission-Computed
C110723:1,3,4,6-tetraacetyl-2-fluoro-2-deoxyglucose; D003287:Contrast Media; D003847:Deoxyglucose