The Danish PET/depression project: poor verbal fluency performance despite normal prefrontal activation in patients with major depression.
The verbal fluency (VF) test is associated with prefrontal and cingulate functioning. We used positron emission tomography (PET) to test the hypothesis that inactivity in these regions can explain why patients with depression often perform poorly on this test. Forty-one patients with major depression and 46 controls were scanned during rest and during activation with the VF test. The differences between the two conditions were mapped for each of the two groups, and between-group differences in the activation pattern were calculated on a voxel-by-voxel basis. As predicted, the patients performed significantly more poorly on the test. In both groups activations were seen in the left anterior cingulate region, the left dorsolateral prefrontal cortex, the left medial prefrontal cortex, and the right cerebellum. Performance was correlated to the cerebral perfusion in to the left occipitotemporal gyrus and the left cerebellum. However, no difference in activation between the two groups was significant. The present study had sufficient power to detect potential differences between the two groups, and the subtraction tasks were appropriate. Therefore, the result supports the notion that abnormalities in the prefrontal cortex in depression are qualitative in nature rather than quantitative; this suggests depression involves dys-coordination of neural activity in the frontal lobes rather than a simple reduction in activity.
Department of Biological Psychiatry, Psychiatric Hospital, Aarhus University Hospitals, DK-8240 Risskov, Denmark. videbech@dadlnet.dk
Poul
P
Videbech
Barbara
B
Ravnkilde
Salomeh
S
Kristensen
Annette
A
Egander
Karin
K
Clemmensen
Niels Anton
NA
Rasmussen
Albert
A
Gjedde
Raben
R
Rosenberg
D000328:Adult; D001479:Basal Ganglia / Q000098:blood supply / Q000503:physiopathology; D001933:Brain Stem / Q000098:blood supply / Q000503:physiopathology; D002531:Cerebellum / Q000098:blood supply / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007031:Hypothalamus / Q000098:blood supply / Q000503:physiopathology; D008297:Male; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000098:blood supply / Q000503:physiopathology; D013788:Thalamus / Q000098:blood supply / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014705:Verbal Behavior