A computational analysis of flanker interference in depression.
BACKGROUND
Depression is characterized by poor executive function, but - counterintuitively - in some studies, it has been associated with highly accurate performance on certain cognitively demanding tasks. The psychological mechanisms responsible for this paradoxical finding are unclear. To address this issue, we applied a drift diffusion model (DDM) to flanker task data from depressed and healthy adults participating in the multi-site Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC) study.


METHODS
One hundred unmedicated, depressed adults and 40 healthy controls completed a flanker task. We investigated the effect of flanker interference on accuracy and response time, and used the DDM to examine group differences in three cognitive processes: prepotent response bias (tendency to respond to the distracting flankers), response inhibition (necessary to resist prepotency), and executive control (required for execution of correct response on incongruent trials).


RESULTS
Consistent with prior reports, depressed participants responded more slowly and accurately than controls on incongruent trials. The DDM indicated that although executive control was sluggish in depressed participants, this was more than offset by decreased prepotent response bias. Among the depressed participants, anhedonia was negatively correlated with a parameter indexing the speed of executive control (r = -0.28, p = 0.007).


CONCLUSIONS
Executive control was delayed in depression but this was counterbalanced by reduced prepotent response bias, demonstrating how participants with executive function deficits can nevertheless perform accurately in a cognitive control task. Drawing on data from neural network simulations, we speculate that these results may reflect tonically reduced striatal dopamine in depression.
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
D G
DG
Dillon
Department of Cognitive, Linguistic, and Psychological Sciences,Brown University,Providence,RI,USA.
T
T
Wiecki
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
P
P
Pechtel
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
C
C
Webb
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
F
F
Goer
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
L
L
Murray
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
M
M
Trivedi
Clinical Research Program,Massachusetts General Hospital,Boston,MA,USA.
M
M
Fava
New York State Psychiatric Institute & Department of Psychiatry,College of Physicians and Surgeons of Columbia University,New York,NY,USA.
P J
PJ
McGrath
New York State Psychiatric Institute & Department of Psychiatry,College of Physicians and Surgeons of Columbia University,New York,NY,USA.
M
M
Weissman
Department of Psychiatry and Behavioral Science,Stony Brook University,Stony Brook,NY,USA.
R
R
Parsey
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
B
B
Kurian
New York State Psychiatric Institute & Department of Psychiatry,College of Physicians and Surgeons of Columbia University,New York,NY,USA.
P
P
Adams
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
T
T
Carmody
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
S
S
Weyandt
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
K
K
Shores-Wilson
Department of Psychiatry,University of Texas Southwestern Medical Center,Dallas,TX,USA.
M
M
Toups
Department of Psychiatry,University of Michigan Health System,Ann Arbor,MI,USA.
M
M
McInnis
New York State Psychiatric Institute & Department of Psychiatry,College of Physicians and Surgeons of Columbia University,New York,NY,USA.
M A
MA
Oquendo
Clinical Research Program,Massachusetts General Hospital,Boston,MA,USA.
C
C
Cusin
Department of Psychiatry,University of Michigan Health System,Ann Arbor,MI,USA.
P
P
Deldin
New York State Psychiatric Institute & Department of Psychiatry,College of Physicians and Surgeons of Columbia University,New York,NY,USA.
G
G
Bruder
Center for Depression, Anxiety and Stress Research,McLean Hospital, Harvard Medical School,Belmont,MA,USA.
D A
DA
Pizzagalli
D000293:Adolescent; D000328:Adult; D000368:Aged; D003071:Cognition; D003863:Depression / Q000523:psychology*; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009483:Neuropsychological Tests; D016032:Randomized Controlled Trials as Topic; D011930:Reaction Time; D011795:Surveys and Questionnaires; D055815:Young Adult
Cognitive control; computational modelling; depression; executive function; flanker