Bipolar I disorder and major depressive disorder show similar brain activation during depression

Abstract

Objectives Despite different treatments and course of illness, depressive symptoms appear similar in major depressive disorder (MDD) and bipolar I disorder (BP-I). This similarity of depressive symptoms suggests significant overlap in brain pathways underlying neurovegetative, mood, and cognitive symptoms of depression. These shared brain regions might be expected to exhibit similar activation in individuals with MDD and BP-I during functional magnetic resonance imaging (fMRI). Methods fMRI was used to compare regional brain activation in participants with BP-I (n = 25) and MDD (n = 25) during a depressive episode as well as 25 healthy comparison (HC) participants. During the scans, participants performed an attentional task that incorporated emotional pictures. Results During the viewing of emotional images, subjects with BP-I showed decreased activation in the middle occipital gyrus, lingual gyrus, and middle temporal gyrus compared to both subjects with MDD and HC participants. During attentional processing, participants with MDD had increased activation in the parahippocampus, parietal lobe, and postcentral gyrus. However, among these regions, only the postcentral gyrus also showed differences between MDD and HC participants. Conclusions No differences in cortico-limbic regions were found between participants with BP-I and MDD during depression. Instead, the major differences occurred in primary and secondary visual processing regions with decreased activation in these regions in BP-I compared to major depression. These differences were driven by abnormal decreases in activation seen in the participants with BP-I. Posterior activation changes are a common finding in studies across mood states in participants with BP-I.

Co-altered functional networks and brain structure in unmedicated patients with bipolar and major depressive disorders

“…Objective markers derived from neuroimaging hold the potential to increase the accuracy of differentiating between BD and MDD patients to an extent that may improve the clinical and functional outcomes for individuals suffering from these disorders (de Almeida and Phillips 2013). In the decade both functional (Cerullo et al 2014; Delvecchio et al 2012) and structural (Kempton et al 2011; Konarski et al 2008) brain abnormalities in BD and MDD have been extensively studied in the magnetic resonance imaging (MRI) literature, however, few studies focused on data-driven, multimodal fusion techniques that exploit the complementary information between fMRI and sMRI in order to differentiate the two mood disorders.…”

Differential failure to deactivate the default mode network in unipolar and bipolar depression

“…Examination of functional connectivity between the amygdala and the orbitofrontal/medial frontal cortex in these patients, however, only revealed evidence of a difference between patients and healthy controls . In a study published after Almeida and Phillips’ review, Cerullo et al . compared 25 BDD and 25 MDD patients as well as 25 healthy controls during performance of a modified form of the continuous performance task where some trials used pictures with both neutral and emotional distractors.…”

Resting-state functional network connectivity in prefrontal regions differs between unmedicated patients with bipolar and major depressive disorders

“…For example, functional magnetic resonance imaging (fMRI) may prove helpful for identifying neurophysiological abnormalities that distinguish BD from MDD. Different patterns of functional activities have been found in BD versus MDD during resting-state or task-based fMRI studies (Almeida et al, 2010; Bertocci et al, 2012; Cerullo et al, 2014; de Almeida et al, 2009; Diler et al, 2013; Taylor Tavares et al, 2008). …”