Depressive rumination is correlated with brain responses during self-related processing

Abstract

Background: Rumination, a tendency to focus on negative self-related thoughts, is a central symptom of depression. Studying the self-related aspect of such symptoms is challenging because of the need to distinguish self effects from the emotional content of task stimuli. This study employed an emotionally neutral self-related paradigm to investigate possible altered self-processing in depression and its link to rumination. Methods: People with major depressive disorder (n = 25) and controls (n = 25) underwent task-based electroencephalogram recording. We studied late event-related potentials, along with low-frequency oscillatory power. We compared electroencephalogram metrics between groups and correlated them with depressive symptoms and reported rumination. Results: Participants with major depressive disorder displayed a difference in late positive potentials across frontocentral electrodes between self-related and non-self-related conditions. We found no such difference in controls. The magnitude of this difference was positively correlated with depressive symptoms and reported rumination. Participants with major depressive disorder also had elevated theta oscillation power at central electrodes in self-related conditions, a finding that we did not see in controls. Limitations: Patients with major depressive disorder were medicated at the time of the study. The group studied was primarily female, so the observed effects may have been sex-specific. Conclusion: Rumination appears to be linked to altered self-related processing in depression, independ ent of stimuli-related emotional confounds. This connection between self-related processing and depression may point to a self disorder as a core component of depression.

Abnormal global signal topography of self modulates emotion dysregulation in major depressive disorder

“…Unlike the intero-and exteroceptive self, the mental self is associated with specifically the CMS while recapitulating the regions of both interoceptive (bilateral insula) and exteroceptive (temporo-parietal junction, premotor) self in a nested hierarchical way [7]. Applying this three-layer topography of self for the first time to MDD, we, based on recent findings [11][12][13][14], hypothesized that post-acute MDD subjects would show increased global brain activity (global signal representation) in specifically the CMS regions of the mental self (and the exteroceptive self).…”

“…The self is known to modulate cognitive, somatic, affective, social, and motor changes [5][6][7][8][9][10] and may therefore be an ideal candidate to provide a more global or basic disturbance (see discussion for definition) of MDD that, in turn, modulates the various functions in an abnormal way. There is indeed strong evidence that the self may be altered in MDD as these subjects show an abnormal focus on their own self in their emotions, cognitions, etc., e.g., increased selffocus [11][12][13][14]. Given the assumption that the self is a more global and basic disturbance of MDD [6,10], one would assume changes in self to be a trait feature (rather than a state feature) which, therefore, should also be present in post-acute MDD [15,16].…”

Brain State Relays Self-Processing and Heartbeat-Evoked Cortical Responses

“…Participants with major depressive disorder (MDD) showed a greater tendency to agree with negative self-referential statements and reject positive ones in comparison to healthy controls [49]. Additionally, the measured EEG activity of MDD patients became less negative over time for self-related decision-making conditions was found to be more negative than the non-self-related one, across frontocentral electrodes, while the healthy group did not [50]. Individuals with anxiety had a lower positive self-view compared to the control group, while those with depression exhibited a stable past-to-present self-view and an improving present-to-future self-view [51].…”

“…The attentional state can manifest in measures such as reaction time [36][37][38][39][40], accuracy [40], recall percentage [41], and N2 posterior-contralateral component, which serves as a neural marker of spatial selective attention [42]. Mood states can be gauged in a self-reported way [43][44][45][46][47][48][49][50][51][52][53][54][55][56] or by physiological indices such as blood pressure [57] and cortisol levels [58].…”