Article

Increased Amygdala and Decreased Dorsolateral Prefrontal BOLD Responses in Unipolar Depression: Related and Independent Features

Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Biological Psychiatry (Impact Factor: 10.26). 02/2007; 61(2):198-209. DOI: 10.1016/j.biopsych.2006.05.048
Source: PubMed

ABSTRACT

Major depressive disorder is characterized by increased and sustained emotional reactivity, which has been linked to sustained amygdala activity. It is also characterized by disruptions in executive control, linked to abnormal dorsolateral prefrontal cortex (DLPFC) function. These mechanisms have been hypothesized to interact in depression. This study explored relationships between amygdala and DLPFC activity during emotional and cognitive information processing in unipolar depression.
Twenty-seven unmedicated patients with DSM-IV unipolar major depressive disorder and 25 never-depressed healthy control subjects completed tasks requiring executive control (digit sorting) and emotional information processing (personal relevance rating of words) during event-related functional magnetic resonance imaging (fMRI) assessment.
Relative to control subjects, depressed subjects displayed sustained amygdala reactivity on the emotional tasks and decreased DLPFC activity on the digit-sorting task. Decreased relationships between the time-series of amygdala and DLPFC activity were observed within tasks in depression, but different depressed individuals showed each type of bias.
Depression is associated with increased limbic activity in response to emotional information processing and decreased DLPFC activity in response to cognitive tasks though these may reflect separate mechanisms. Depressed individuals also display decreased relationships between amygdala and DLPFC activity, potentially signifying decreased functional relationships among these structures.

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    • "Furthermore, we expected the H-EC group to show enhanced resting-state functional connectivity between the amygdala and prefrontal regions implicated in the flanker task. These predictions were based on previous findings showing that nonemotional EC training can reduce emotion dysregulation symptoms (Calkins et al., 2014; Siegle et al., 2007; although as noted contradicting evidence was shown by Schweizer et al., 2011), as well as on data from our lab showing that the behavioral (Cohen et al., 2011, 2012, 2015b) and psychophysiological (Cohen et al., 2015c) reactions to aversive information are attenuated following the recruitment of EC. "
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    ABSTRACT: The ability to regulate emotions is essential for adaptive behavior. This ability is suggested to be mediated by the connectivity between prefrontal brain regions and the amygdala. Yet, it is still unknown whether the ability to regulate emotions can be trained by using a non-emotional procedure, such as the recruitment of executive control (EC). Participants who were trained using a high-frequent executive control (EC) task (80% incongruent trials) showed reduced amygdala reactivity and behavioral interference of aversive pictures. These effects were observed only following multiple-session training and not following one training session. In addition, they were not observed for participants exposed to low-frequent EC training (20% incongruent trials). Resting-state functional connectivity analysis revealed a marginally significant interaction between training groups and change in the connectivity between the amygdala and the right inferior frontal gyrus (IFG). Amygdala-IFG connectivity was significantly increased following the training only in the high-frequent EC training group. These findings are the first to show that non-emotional training can induce changes in amygdala reactivity to aversive information and alter amygdala-prefrontal connectivity.
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    • "The ACC and the superior and inferior lateral frontal regions are assumed to play a central role in the top–down regulation of negative emotions by inhibiting and controlling the activation in limbic regions (Aron et al., 2004; Ochsner et al., 2004; Lieberman et al., 2007; Shackman et al., 2009). This top–down pathway seems to be centrally involved in successful emotion regulation , and there is growing evidence that the dorsolateral prefrontal cortex (dlPFC) is dysfunctional in its response to negative selfreferential material in clinically depressed patients (Siegle et al., 2007; Hooley et al., 2009; Lemogne et al., 2009). Correspondingly, Hooley et al. (2005, 2009, 2012) showed that remitted depressed patients failed to activate the dlPFC, predominantly in the right hemisphere , when they heard tape-recorded critical utterances by their own mothers. "

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    • "The ACC and the superior and inferior lateral frontal regions are assumed to play a central role in the top–down regulation of negative emotions by inhibiting and controlling the activation in limbic regions (Aron et al., 2004; Ochsner et al., 2004; Lieberman et al., 2007; Shackman et al., 2009). This top–down pathway seems to be centrally involved in successful emotion regulation , and there is growing evidence that the dorsolateral prefrontal cortex (dlPFC) is dysfunctional in its response to negative selfreferential material in clinically depressed patients (Siegle et al., 2007; Hooley et al., 2009; Lemogne et al., 2009). Correspondingly, Hooley et al. (2005, 2009, 2012) showed that remitted depressed patients failed to activate the dlPFC, predominantly in the right hemisphere , when they heard tape-recorded critical utterances by their own mothers. "

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