Differential brain activation during response inhibition in bipolar and attention-deficit hyperactivity disorders.
OBJECTIVE
To identify differential patterns of brain activation between adolescents with bipolar disorder and adolescents with attention-deficit hyperactivity disorder (ADHD) to better understand the neurophysiology of both disorders. We hypothesized that subjects with ADHD would show altered activation in brain regions involved in executive and sustained attention. In contrast, we hypothesized that bipolar subjects would show altered brain activation in regions responsible for emotionally homeostasis, including the striatum and amygdala.


METHODS
Functional magnetic resonance imaging was performed during a continuous performance task with a response inhibition component in 11 adolescents with bipolar disorder during a manic episode, 10 adolescents with ADHD, and 13 healthy adolescents.


RESULTS
There were no differences in behavioural performance among the three groups. Compared with bipolar subjects, subjects with ADHD showed increased activation in the superior temporal lobe during successful response inhibition. Although bipolar subjects did not show activation differences in the striatum or amygdala compared with ADHD subjects, increased left parahippocampal activation in the bipolar group was associated with increased manic symptoms.


CONCLUSIONS
The patterns of brain activation observed in the current study support divergent patterns of neurophysiological dysfunction in individuals with bipolar disorder as compared with those with ADHD. Therefore, the impulsive behaviour seen in both disorders may be the consequence of dysfunction in different brain regions, and further research may help identify neurobiological markers that are specific to each condition.
Division of Bipolar Disorders Research, Department of Psychiatry, and The Center for Imaging Research, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0559, USA. cerullmc@ucmail.uc.edu
Michael A
MA
Cerullo
Caleb M
CM
Adler
Martine
M
Lamy
James C
JC
Eliassen
David E
DE
Fleck
Stephen M
SM
Strakowski
Melissa P
MP
DelBello
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods / Q000523:psychology*; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000523:psychology; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology