Differences in resting corticolimbic functional connectivity in bipolar I euthymia.
OBJECTIVE
We examined resting state functional connectivity in the brain between key emotion regulation regions in bipolar I disorder to delineate differences in coupling from healthy subjects.


METHODS
Euthymic subjects with bipolar I disorder (n = 20) and matched healthy subjects (n = 20) participated in a resting state functional magnetic resonance imaging scan. Low-frequency fluctuations in blood oxygen level-dependent (BOLD) signal were correlated in the six connections between four anatomically defined nodes: left and right amygdala and left and right ventrolateral prefrontal cortex (vlPFC). Seed-to-voxel connectivity results were probed for commonly coupled regions. Following this, an identified region was included in a mediation analysis to determine the potential of mediation.


RESULTS
The bipolar I disorder group exhibited significant hyperconnectivity between right amygdala and right vlPFC relative to healthy subjects. The connectivity between these regions in the bipolar I disorder group was partially mediated by activity in the anterior cingulate cortex (ACC).


CONCLUSIONS
Greater coupling between right amygdala and right vlPFC and their partial mediation by the ACC were found in bipolar I disorder subjects in remission and in the absence of a psychological task. These findings have implications for a trait-related and clinically important imaging biomarker.
Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior Center for Cognitive Neuroscience, University of California at Los Angeles, CA 90095, USA. storrisi@ucla.edu
Salvatore
S
Torrisi
Teena D
TD
Moody
Nathalie
N
Vizueta
Moriah E
ME
Thomason
Martin M
MM
Monti
Jennifer D
JD
Townsend
Susan Y
SY
Bookheimer
Lori L
LL
Altshuler
D000328:Adult; D001714:Bipolar Disorder / Q000473:pathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000098:blood supply / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008032:Limbic System / Q000098:blood supply / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000098:blood supply / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D012146:Rest
D010100:Oxygen