A preliminary study of the neural mechanisms of frustration in pediatric bipolar disorder using magnetoencephalography

Abstract

Background: Irritability is prevalent and impairing in pediatric bipolar disorder (BD) but has been minimally studied using neuroimaging techniques. We used magnetoencephalography (MEG) to study theta band oscillations in the anterior cingulate cortex (ACC) during frustration in BD youth. ACC theta power is associated with attention to emotional stimuli, and the ACC may mediate responses to frustrating stimuli.

Methods: We used the affective Posner task, an attention paradigm that uses rigged feedback to induce frustration, to compare 20 medicated BD youth (14.9+/-2.0 years; 45% male) and 20 healthy controls (14.7+/-1.7 years; 45% male). MEG measured neuronal activity after negative and positive feedback; we also compared groups on reaction time, response accuracy, and self-reported affect. Patients met strict DSM-IV BD criteria and were euthymic. Controls had no psychiatric history.

Results: BD youth reported more negative affective responses than controls. After negative feedback, BD subjects, relative to controls, displayed greater theta power in the right ACC and bilateral parietal lobe. After positive feedback, BD subjects displayed lower theta power in the left ACC than did controls. Correlations between MEG, behavior, and affect were nonsignificant.

Conclusion: In this first MEG study of BD youth, BD youth displayed patterns of theta oscillations in the ACC and parietal lobe in response to frustration-inducing negative feedback that differed from healthy controls. These data suggest that BD youth may display heightened processing of negative feedback and exaggerated self-monitoring after frustrating emotional stimuli. Future studies are needed with unmedicated bipolar youth, and comparison ADHD and anxiety groups.

Figure 1. Affective Posner task

Figure details the affective Posner task, which examines attention during different emotional contexts, including frustration in response to rigged negative feedback.

Figure 2. Between-group (BD vs. CON) comparison of Stockwell transformations of raw theta power at right medial frontal sensors

Note: BD = bipolar disorder; CON = control. Figure displays the comparison between BD and CON samples of the time-frequency representations of the averaged raw theta power in response to the presentation of negative feedback as compared to theta power in response to the presentation of the fixation cross. 0.0 on the X-axis reflects the onset of feedback or fixation cross.

Figures 3 & 4. Theta band power differences between youth with bipolar disorder and healthy controls in the left and right anterior cingulate cortex (ACC)

Note: BD = bipolar disorder; CON = control. Figure displays the locations in the left ACC (BA 10/9; 1,47,14) where BD subjects (N=20) had lower theta power than controls (N=20) following positive feedback, and the right ACC (BA 32; 17,31,28) where BD subjects had greater theta power than controls following negative feedback.

Figures 3 & 4. Theta band power differences between youth with bipolar disorder and healthy controls in the left and right anterior cingulate cortex (ACC)

Note: BD = bipolar disorder; CON = control. Figure displays the locations in the left ACC (BA 10/9; 1,47,14) where BD subjects (N=20) had lower theta power than controls (N=20) following positive feedback, and the right ACC (BA 32; 17,31,28) where BD subjects had greater theta power than controls following negative feedback.

Figures 5 & 6. Theta band power differences between youth with bipolar disorder and healthy controls in the left inferior parietal lobule (IPL) and right superior parietal lobule (SPL)

Note: BD = bipolar disorder; CON = control. Figure displays the locations in the left IPL (BA 40; -55,-43,35) and right SPL (BA 7; 20,-67,45) where BD subjects (N=20) had greater theta power than controls (N=20) following negative feedback.

Figures 5 & 6. Theta band power differences between youth with bipolar disorder and healthy controls in the left inferior parietal lobule (IPL) and right superior parietal lobule (SPL)

Note: BD = bipolar disorder; CON = control. Figure displays the locations in the left IPL (BA 40; -55,-43,35) and right SPL (BA 7; 20,-67,45) where BD subjects (N=20) had greater theta power than controls (N=20) following negative feedback.