Can't shake that feeling: event-related fMRI assessment of sustained amygdala activity in response to emotional information in depressed individuals.
BACKGROUND
Previous research suggests that depressed individuals engage in prolonged elaborative processing of emotional information. A computational neural network model of emotional information processing suggests this process involves sustained amygdala activity in response to processing negative features of information. This study examined whether brain activity in response to emotional stimuli was sustained in depressed individuals, even following subsequent distracting stimuli.


METHODS
Seven depressed and 10 never-depressed individuals were studied using event-related functional magnetic resonance imaging during alternating 15-sec emotional processing (valence identification) and non-emotional processing (Sternberg memory) trials. Amygdala regions were traced on high-resolution structural scans and co-registered to the functional data. The time course of activity in these areas during emotional and non-emotional processing trials was examined.


RESULTS
During emotional processing trials, never-depressed individuals displayed amygdalar responses to all stimuli, which decayed within 10 sec. In contrast, depressed individuals displayed sustained amygdala responses to negative words that lasted throughout the following non-emotional processing trials (25 sec later). The difference in sustained amygdala activity to negative and positive words was moderately related to self-reported rumination.


CONCLUSIONS
Results suggest that depression is associated with sustained activity in brain areas responsible for coding emotional features.
Siegle
Greg J
GJ
University of Pittsburgh Medical School and Department of Veterans Affairs Medical Center, Pittsburgh, Pennsylvania, USA.
Steinhauer
Stuart R
SR
Thase
Michael E
ME
Stenger
V Andrew
VA
Carter
Cameron S
CS
D000328:Adult; D000679:Amygdala / Q000473:pathology*; D000704:Analysis of Variance; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D003866:Depressive Disorder / Q000473:pathology* / Q000503:physiopathology* / Q000523:psychology; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D013997:Time Factors