Cortical inefficiency in patients with unipolar depression: an event-related FMRI study with the Stroop task.
BACKGROUND
The present study is aimed to examine the neuronal correlates of Stroop interference in medication-free patients with major depressive disorder.


METHODS
Sixteen patients fulfilling Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for unipolar depression and 16 healthy control subjects matched for age, gender, and education were included. All subjects underwent an event-related functional magnetic resonance imaging (fMRI) design with an adapted version of the Stroop task including congruent and incongruent task conditions. The fMRI experiment was conducted on a 1.5 T magnetic resonance (MR) scanner, and item responses were given manually by the subjects.


RESULTS
With regard to behavioral performance, patients revealed no differences in both reaction time and accuracy relative to control subjects. With regard to brain activations, direct comparison of patients with control subjects in the interference condition revealed hyperactivity in rostral anterior cingulate gyrus (rACG) and left dorsolateral prefrontal cortex (DLPFC) in depressive patients, which correlated strongly with the Stroop interference.


CONCLUSIONS
The study provides new evidence for the functioning and dissociation of the anterior cingulate in depressed patients. The greater prefrontal activation may reflect a cortical inefficiency due to hyperactivity in rACG enhancing the cognitive interferences from the emotional state.
Wagner
Gerd
G
Department of Psychiatry, University of Jena, Jena, Germany. wagner.gerd@uni-jena.de
Sinsel
Esther
E
Sobanski
Thomas
T
Köhler
Sabine
S
Marinou
Varvara
V
Mentzel
Hans-Joachim
HJ
Sauer
Heinrich
H
Schlösser
Ralf G M
RG
D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D003118:Color Perception / Q000502:physiology*; D003220:Conflict, Psychological; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011932:Reading; D012016:Reference Values; D012660:Semantics; D013223:Statistics as Topic