(A) Functional hypoactivation (Z-score) in bipolar patients compared to
controls visualized on the inflated Freesurfer atlas. Significant clusters of
reduced activation show the inferior frontal gyrus (ifg), superior frontal gyrus
(sfg), medial frontal gyrus (mfg), insula (ins), caudal anterior cingulate gyrus
(cACC), superior temporal gyrus (stg), and inferior parietal (ip) regions. (B)
Partial correlations between mean BOLD activation and a priori
mean region-of-interest (ROI) cortical thickness in the right caudal anterior
cingulate (cACC), controlling for age, are displayed separately for bipolar (BP)
patients and controls (CON). Only patients demonstrated a significant
correlation (r = 0.33, p = 0.026) between
thickness and functional activation. (C) Significant disease interaction effect
(p=0.047) was found for the functional activation and cortical thickness in the
left inferior frontal gyrus which consists of the caudal middle frontal, lateral
orbitofrontal, medial orbitofrontal, pars orbitalis, pars triangularis, pars
opercularis, rostral middle frontal, superior frontal, and the frontal pole ROIs
merged together. It was also observed that the left frontal lobe mean
activations were significantly negatively correlated (r =
−0.34, p = 0.021) with the respective mean cortical
thickness in patients when controlled for age and the duration of the euthymic
period but not in controls.