[Abstract Title]. - Society for Neuroscience

Title: Modulatory effects of comorbid anxiety on neuronal circuitry in depression using current
cource coherence
Authors: *H. FARAHBOD 1,2 , I. A. COOK 2 , D. SCHAIRER 2 , A. KORB 2 , A. F. LEUCHTER 2 ;
1 NPI, 2 UCLA Lab. of Brain, Behavior, and Pharmacology, Semel Inst., UCLA, Los Angeles, CA
Abstract: Major Depressive Disorder (MDD) with comorbid anxiety symptoms has a poorer
treatment outcome than MDD without anxiety. This difference in outcome may reflect
neurophysiologic differences between these two groups. We hypothesized that MDD subjects
with higher levels of anxiety would have stronger neural connectivity between brain regions that
connect the insula and amygdala. We used quantitative electroencephalographic (QEEG), current
source coherence (CSC) to assess real-time connectivity between deeper brain regions. CSC
expands the conventional surface EEG coherence measure by examining signals from deeper
structures determined via LORETA transformation, and yields estimates of connectivity in terms
of shared activity. Regions of interest (ROIs) included the dorsolateral prefrontal cortex
(DLPFC), orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), medial-temporal cortex
(MT), insula, and the amygdala (Amyg). 8 adults with MDD and different levels of anxiety, and
8 healthy controls participated in this study. Severity of each condition was determined using the
Hamilton Depression Rating Scale and the Hamilton Anxiety Scale. QEEG was recorded during
performance of cognitive tasks while viewing images of faces with fearful expressions. Thetaband
CSC was calculated for regions linking the amygdala, DLPFC, ACC, OFC, MT, and insula.
We found significant connectivity differences in MDD patients relative to controls in ROIs, e.g.,
left Insula-Amyg circuit (t(13)=2.32, p