major depressive disorder
Research Papers
Showing 6 of 1116 Aberrant emotional memory encoding in a transdiagnostic sample of patients with intrusive memories
Emotion can affect the way in which experiences are stored in our memory. The dual representation account proposes that traumatic events may be encoded as fragmented sensory-perceptual details without a broader conceptual organisation. This can result in involuntary retrieval of perceptual information triggered by environmental cues without the associated context – a phenomenon referred to as intrusive memories.Currently, it is unknown whether individuals who experience intrusive memories have an underlying vulnerability to aberrant memory encoding, which may lead to the onset or maintenance of symptoms.In Experiment 1, we examined memory recall for neutral and negative images in a transdiagnostic sample of patients with intrusive memories (N = 36), compared to healthy controls (N = 44). Clinical diagnoses in the patient sample included Post-Traumatic Stress Disorder, Major Depressive Disorder, Social Anxiety Disorder, Generalised Anxiety Disorder, Panic Disorder and Other Specified Feeding or Eating Disorders. We excluded participants currently taking psychotropic medication. At encoding, participants viewed neutral, negative and mixed valence image pairs. In the test phase, participants were presented with cues and, if recognised, were asked to recall the associated image. We found a significant group effect, with patients demonstrating impaired item memory for negative images [F(1,280) = 4.435, p = 0.036], relative to healthy controls. This group difference might suggest that individuals with intrusive memories experienced greater sensitivity to negative stimuli, leading to disruptions in memory encoding. Recent work highlights attention maintenance on threat and high levels of threat-related emotional arousal in anxiety- and fear-related disorders which may be one factor driving the disruption to item memory observed in our clinical population.For Experiment 2, in a separate sample of healthy participants (N = 18) we measured eye-tracking behaviour during the encoding phase of the same task. Healthy participants showed greater item memory [F(3, 136 = 2.893, p = 0.0377] and avoidance of fixation [F(1, 110) = 4.898, p = 0.029] on highly arousing, negative stimuli relative to neutral. This might suggest that a shift in attention away from negative stimuli prevents item memory impairments for emotional information.Our future work will identify biological factors driving attentional biases and higher emotional arousal in clinical populations.
View Full Paper →Neurofeedback training in major depressive disorder: A systematic review of clinical efficacy, study quality and reporting practices
Major depressive disorder (MDD) is the leading cause of disability worldwide. Neurofeedback training has been suggested as a potential additional treatment option for MDD patients not reaching remission from standard care (i.e., psychopharmacology and psychotherapy). Here we systematically reviewed neurofeedback studies employing electroencephalography, or functional magnetic resonance-based protocols in depressive patients. Of 585 initially screened studies, 24 were included in our final sample (N = 480 patients in experimental and N = 194 in the control groups completing the primary endpoint). We evaluated the clinical efficacy across studies and attempted to group studies according to the control condition categories currently used in the field that affect clinical outcomes in group comparisons. In most studies, MDD patients showed symptom improvement superior to the control group(s). However, most articles did not comply with the most stringent study quality and reporting practices. We conclude with recommendations on best practices for experimental designs and reporting standards for neurofeedback training.
View Full Paper →Altered task-based and resting-state amygdala functional connectivity following real-time fMRI amygdala neurofeedback training in major depressive disorder
Background We have previously shown that in participants with major depressive disorder (MDD) trained to upregulate their amygdala hemodynamic response during positive autobiographical memory (AM) recall with real-time fMRI neurofeedback (rtfMRI-nf) training, depressive symptoms diminish. Here, we assessed the effect of rtfMRI-nf on amygdala functional connectivity during both positive AM recall and rest. Method The current manuscript consists of a secondary analysis on data from our published clinical trial of neurofeedback. Patients with MDD completed two rtfMRI-nf sessions (18 received amygdala rtfMRI-nf, 16 received control parietal rtfMRI-nf). One-week prior-to and following training participants also completed a resting-state fMRI scan. A GLM-based functional connectivity analysis was applied using a seed ROI in the left amygdala. We compared amygdala functional connectivity changes while recalling positive AMs from the baseline run to the final transfer run during rtfMRI-nf training, as well during rest from the baseline to the one-week follow-up visit. Finally, we assessed the correlation between change in depression scores and change in amygdala connectivity, as well as correlations between amygdala regulation success and connectivity changes. Results Following training, amygdala connectivity during positive AM recall increased with widespread regions in the frontal and limbic network. During rest, amygdala connectivity increased following training within the fronto-temporal-limbic network. During both task and resting-state analyses, amygdala-temporal pole connectivity decreased. We identified increased amygdala-precuneus and amygdala-inferior frontal gyrus connectivity during positive memory recall and increased amygdala-precuneus and amygdala-thalamus connectivity during rest as functional connectivity changes that explained significant variance in symptom improvement. Amygdala-precuneus connectivity changes also explain a significant amount of variance in neurofeedback regulation success. Conclusions Neurofeedback training to increase amygdala hemodynamic activity during positive AM recall increased amygdala connectivity with regions involved in self-referential, salience, and reward processing. Results suggest future targets for neurofeedback interventions, particularly interventions involving the precuneus.
View Full Paper →Amygdala real-time functional magnetic resonance imaging neurofeedback for major depressive disorder: A review
Advances in imaging technologies have allowed for the analysis of functional magnetic resonance imaging data in real-time (rtfMRI), leading to the development of neurofeedback (nf) training. This rtfMRI-nf training utilizes functional magnetic resonance imaging (fMRI) tomographic localization capacity to allow a person to see and regulate the localized hemodynamic signal from his or her own brain. In this review, we summarize the results of several studies that have developed and applied neurofeedback training to healthy and depressed individuals with the amygdala as the neurofeedback target and the goal to increase the hemodynamic response during positive autobiographical memory recall. We review these studies and highlight some of the challenges and advances in developing an rtfMRI-nf paradigm for broader use in psychiatric populations. The work described focuses on our line of research aiming to develop the rtfMRI-nf into an intervention, and includes a discussion of the selection of a region of interest for feedback, selecting a control condition, behavioral and cognitive effects of training, and predicting which participants are most likely to respond well to training. While the results of these studies are encouraging and suggest the clinical potential of amygdala rtfMRI-nf in alleviating symptoms of major depressive disorder, larger studies are warranted to confirm its efficacy.
View Full Paper →Effects of salience-network-node neurofeedback training on affective biases in major depressive disorder
Neural models of major depressive disorder (MDD) posit that over-response of components of the brain's salience network (SN) to negative stimuli plays a crucial role in the pathophysiology of MDD. In the present proof-of-concept study, we tested this formulation directly by examining the affective consequences of training depressed persons to down-regulate response of SN nodes to negative material. Ten participants in the real neurofeedback group saw, and attempted to learn to down-regulate, activity from an empirically identified node of the SN. Ten other participants engaged in an equivalent procedure with the exception that they saw SN-node neurofeedback indices from participants in the real neurofeedback group. Before and after scanning, all participants completed tasks assessing emotional responses to negative scenes and to negative and positive self-descriptive adjectives. Compared to participants in the sham-neurofeedback group, from pre- to post-training, participants in the real-neurofeedback group showed a greater decrease in SN-node response to negative stimuli, a greater decrease in self-reported emotional response to negative scenes, and a greater decrease in self-reported emotional response to negative self-descriptive adjectives. Our findings provide support for a neural formulation in which the SN plays a primary role in contributing to negative cognitive biases in MDD.
View Full Paper →The efficacy of neurofeedback among patients with major depressive disorder: preliminary study
Introduction: Alpha asymmetry of the left and right frontal hemisphere is a potential biomarker for major depressive disorder (MDD). Neurofeedback (NFB) is a clinical intervention program for regulating brain activity and decreasing alpha asymmetry. The purpose of this study was to explore the efficacy of NFB among patients with MDD. Methods: Fourteen patients with MDD were randomly assigned to a NFB group that received neurofeedback training 1 hr weekly for 6 weeks and to a control group that was treated without training. A 5-min resting baseline of electroencephalogram (EEG) was recorded at F3 (left) and F4 (right) before and after NFB, and the alpha power was analyzed as an asymmetry index (A1). Results: The A1 of the control group decreased from pre- to post-interventions while the A1 of the NFB group increased from pre- to post-interventions. Anxiety and depression scores of the responder group decreased from pre- to post-interventions, while the scores of the non-responder group increased from pre- to post-interventions. Conclusion: Patients who respond to the NFB training showed a decrease in anxiety and depression scores compared to those who do not. This study indicated that NFB could improve left frontal hypoarousal or right frontal hyperarousal among patients with MDD.
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