Normal amygdala activation but deficient ventrolateral prefrontal activation in adults with bipolar disorder during euthymia

Abstract

Functional neuroimaging studies have implicated the involvement of the amygdala and ventrolateral prefrontal cortex (vlPFC) in the pathophysiology of bipolar disorder. Hyperactivity in the amygdala and hypoactivity in the vlPFC have been reported in manic bipolar patients scanned during the performance of an affective faces task. Whether this pattern of dysfunction persists during euthymia is unclear. Using functional magnetic resonance imaging (fMRI), 24 euthymic bipolar and 26 demographically matched healthy control subjects were scanned while performing an affective task paradigm involving the matching and labeling of emotional facial expressions. Neuroimaging results showed that, while amygdala activation did not differ significantly between groups, euthymic patients showed a significant decrease in activation of the right vlPFC (BA47) compared to healthy controls during emotion labeling. Additionally, significant decreases in activation of the right insula, putamen, thalamus and lingual gyrus were observed in euthymic bipolar relative to healthy control subjects during the emotion labeling condition. These data, taken in context with prior studies of bipolar mania using the same emotion recognition task, could suggest that amygdala dysfunction may be a state-related abnormality in bipolar disorder, whereas vlPFC dysfunction may represent a trait-related abnormality of the illness. Characterizing these patterns of activation is likely to help in understanding the neural changes related to the different mood states in bipolar disorder, as well as changes that represent more sustained abnormalities. Future studies that assess mood-state related changes in brain activation in longitudinal bipolar samples would be of interest.

Modulation of brain response to emotional conflict as a function of current mood in bipolar disorder: Preliminary findings from a follow-up state-based fMRI study

“…However, our findings are consistent with previous Stroop studies that reported reduced activation to conflict trials in IFG/MFG, medial SFG/SMA, parietal cortex, and basal ganglia in euthymic BD patients (Malhi et al, 2005;Strakowski et al, 2005;Kronhaus et al, 2006;Roth et al, 2006;Pompei et al, 2011). Stroop-like conflict has rarely been studied during affective episodes, but decreased activity in the IFG, together with hypoactivation of the basal ganglia, thalamus and/or parietal areas, was reported during inhibition and emotion categorization tasks in manic and depressed patients, as well as euthymic patients Foland-Ross et al, 2012;Vizueta et al, 2012). Together with our findings, these studies suggest that functional anomalies in ventrolateral prefrontal-striato-pallido-thalamic networks may persist in BD patients across clinical changes, but to a different degree depending on mood and available cognitive resources.…”

Deficits in recognition, identification, and discrimination of facial emotions in patients with bipolar disorder

“…The ability to recognize emotion expressions was evaluated in both groups using the following three tasks: 1) the Facial Emotion Identification Test (FEIT) [8][9][10][11][12][13][14][15][16] shows 19 black and white pictures of six basic emotions (happy, sad, anger, surprise, disgust, and shame) which the participant must identify; 2) the Facial Emotion Discrimination Test (FEDT) [8][9][10][11][12][13][14][15][16] comprises 30 pairs of black and white pictures with faces presented concurrently. This test requires the participant to determine whether the two faces in each pair of pictures are displaying the same or different emotions; and 3) Emotion Recognition-40 (ER40).…”

“…This test requires the participant to determine whether the two faces in each pair of pictures are displaying the same or different emotions; and 3) Emotion Recognition-40 (ER40). [9][10][11][12][13][14][15][16][17] This test shows 40 pictures in which participants have to identify the displayed emotion. There are five options: anger, sad, fear, happy, and no emotion.…”

“…This test consists of 10 brief stories that describe interactions ending in a hint; the individual has to derive the content of said hint. [10][11][12][13][14][15][16][17][18] Clinical features included in the study were the following: number and type of episodes, duration of illness, previous psychotic symptoms, number of hospitalizations, and type of BD (I or II). The presence of depressive symptoms was assessed with the Spanish version of the Hamilton Depression Rating Scale (HDRS) and manic symptoms with the Young Mania Rating Scale (YMRS).…”

“…9 Several neuroimaging studies have explored the neural correlates of this trait deficit of emotion recognition in BD. [10][11][12][13] Despite some mixed findings, they overall propose an abnormally increased activity in subcortical and limbic emotion processing regions (e.g., the amygdala) and reduced responses in prefrontal cortical emotion regulation regions (see reviews). 14,15 The main goal of this study is to analyze the recognition, identification, and discrimination of facial emotions in a group of outpatients with BD compared with a control sample of healthy subjects.…”