fMRI during affect discrimination in bipolar affective disorder.
ABSTRACT It has been hypothesized that disturbances in affect may represent distinct etiologic factors for bipolar affective disorder. The neural mechanisms mediating affective processes and their relationship to brain development and the pathophysiology of bipolar affective disorder remain to be clarified. Recent advances in neuroimaging techniques have made possible the non-invasive examination of specific brain regions during cortical challenge paradigms. This study reports findings based on fMRI data acquired during fearful and happy affect recognition paradigms in patients with bipolar affective disorder and in healthy adult subjects.
Prior to the scan, subjects were instructed to view the stimuli and to identify the type of facial expression presented. Echo planar scanning was performed on a 1.5 Tesla scanner which had been retrofitted with a whole body echo planar coil, using a head coil.
The data indicate that in adult subjects with bipolar affective disorder, there is a reduction in dorsolateral prefrontal cortex activation and an increase in amygdalar activation in response to fearful facial affect. In a healthy comparison group, signal intensity changes were not found in these regions. In addition, although the patients with bipolar affective disorder completed the task demands, they demonstrated an impaired ability to correctly identify fearful facial affect but not the happy facial affect displayed.
These findings are consistent with the hypothesis that in some patients with bipolar affective disorder, there may be a reduction of frontal cortical function which may be associated with affective as well as attentional processing deficits.
Full-textDOI: · Available from: William D. S. Killgore, Jul 06, 2015
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ABSTRACT: Social cognitive difficulties are common in the acute phase of bipolar disorder and to a lesser extent during the euthymic stage, and imaging studies of social cognition in euthymic bipolar disorder have implicated mirror system brain regions. This study aimed to use a novel multimodal approach (i.e. including both TMS and EEG) to investigate mirror systems in bipolar disorder. 15 individuals with euthymic bipolar disorder and 16 healthy controls participated in this study. Single-pulse TMS was applied to the optimal site in the primary motor cortex (M1) which stimulates the muscle of interest during the observation of hand movements (goal-directed or interacting) designed to elicit mirror system activity. Single EEG electrodes (C3, CZ, C4) recorded mu rhythm modulation concurrently. Results revealed that the patient group showed significantly less mu suppression compared to healthy controls. Surprisingly, motor resonance was not significantly different overall between groups, however, bipolar disorder participants showed a pattern of reduced reactivity on some conditions. While preliminary, this study indicates a potential mirror system deficit in euthymic bipolar disorder which may contribute to the pathophysiology of the disorder.Social Neuroscience 03/2015; DOI:10.1080/17470919.2015.1029140 · 2.87 Impact Factor
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ABSTRACT: Research in bipolar disorder (BD) implicates fronto-limbic-striatal dysfunction during face emotion processing but it is unknown how such dysfunction varies by task demands, face emotion and patient age. Method During functional magnetic resonance imaging (fMRI), 181 participants, including 62 BD (36 children and 26 adults) and 119 healthy comparison (HC) subjects (57 children and 62 adults), engaged in constrained and unconstrained processing of emotional (angry, fearful, happy) and non-emotional (neutral) faces. During constrained processing, subjects answered questions focusing their attention on the face; this was processed either implicitly (nose width rating) or explicitly (hostility; subjective fear ratings). Unconstrained processing consisted of passive viewing. Pediatric BD rated neutral faces as more hostile than did other groups. In BD patients, family-wise error (FWE)-corrected region of interest (ROI) analyses revealed dysfunction in the amygdala, inferior frontal gyrus (IFG), anterior cingulate cortex (ACC) and putamen. Patients with BD showed amygdala hyperactivation during explicit processing (hostility ratings) of fearful faces and passive viewing of angry and neutral faces but IFG hypoactivation during implicit processing of neutral and happy faces. In the ACC and striatum, the direction of dysfunction varied by task demand: BD demonstrated hyperactivation during unconstrained processing of angry or neutral faces but hypoactivation during constrained processing (implicit or explicit) of angry, neutral or happy faces. Findings suggest amygdala hyperactivation in BD while processing negatively valenced and neutral faces, regardless of attentional condition, and BD IFG hypoactivation during implicit processing. In the cognitive control circuit involving the ACC and putamen, BD neural dysfunction was sensitive to task demands.Psychological Medicine 08/2013; DOI:10.1017/S003329171300202X · 5.43 Impact Factor