Neurophysiological correlates of disorder-related autobiographical memory in anorexia nervosa.

BACKGROUND: Anorexia nervosa (AN) is characterized by an overgeneralization of food/body-related autobiographical memories (AM). This is regarded as an emotion regulation strategy with adverse long-term effects implicated in disorder maintenance and treatment resistance. Therefore, we aimed to examine neural correlates of food/body-related AM-recall in AN. METHODS: Twenty-nine female patients with AN and 30 medication-free age-sex-matched normal-weight healthy controls (HC) underwent functional magnetic resonance imaging while recalling AMs in response to food/body-related and neutral cue words. To control for general knowledge retrieval, participants engaged in a semantic generation and riser detection task. RESULTS: In comparison to HC, patients with AN generated fewer and less specific AMs in response to food/body-related words, but not for neutral cue words. Group comparisons revealed reduced activation in regions associated with self-referential processing and memory retrieval (precuneus and angular gyrus) during the retrieval of specific food/body-related AM in patients with AN. Brain connectivity in regions associated with memory functioning and executive control was reduced in patients with AN during the retrieval of specific food/body-related AM. Finally, resting-state functional connectivity analysis revealed no differences between groups, arguing against a general underlying disconnection of brain networks implicated in memory and emotional processing in AN. CONCLUSIONS: These results indicate impaired neural processing of food/body-related AM in AN, with a reduced involvement of regions involved in self-referential processing. Our findings are discussed as possible neuronal correlates of emotional avoidance in AN and provide new insights of AN-pathophysiology underscoring the importance of targeting dysfunctional emotion regulation strategies during treatment.

Consensus on the reporting and experimental design of clinical and cognitive-behavioural neurofeedback studies (CRED-nf checklist).

Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.

Effect of deactivation of activity patterns related to smoking cue reactivity on nicotine addiction.

With approximately 75% of smokers resuming cigarette smoking after using the Gold Standard Programme for smoking cessation, investigation into novel therapeutic approaches is warranted. Typically, smoking cue reactivity is crucial for smoking behaviour. Here we developed a novel closed-loop, smoking cue reactivity patterns EEG-based neurofeedback protocol and evaluated its therapeutic efficacy on nicotine addiction. During an evoked smoking cue reactivity task participants' brain activity patterns corresponding to smoking cues were obtained with multivariate pattern analysis of all EEG channels data, then during neurofeedback the EEG activity patterns of smoking cue reactivity were continuously deactivated with adaptive closed-loop training. In a double-blind, placebo-controlled, randomized clinical trial, 60 nicotine-dependent participants were assigned to receive two neurofeedback training sessions (∼1 h/session) either from their own brain (n = 30, real-feedback group) or from the brain activity pattern of a matched participant (n = 30, yoked-feedback group). Cigarette craving and craving-related P300 were assessed at pre-neurofeedback and post-neurofeedback. The number of cigarettes smoked per day was assessed at baseline, 1 week, 1 month, and 4 months following the final neurofeedback visit. In the real-feedback group, participants successfully deactivated EEG activity patterns of smoking cue reactivity. The real-feedback group showed significant decrease in cigarette craving and craving-related P300 amplitudes compared with the yoked-feedback group. The rates of cigarettes smoked per day at 1 week, 1 month and 4 months follow-up decreased 30.6%, 38.2%, and 27.4% relative to baseline in the real-feedback group, compared to decreases of 14.0%, 13.7%, and 5.9% in the yoked-feedback group. The neurofeedback effects on craving change and smoking amount at the 4-month follow-up were further predicted by neural markers at pre-neurofeedback. This novel neurofeedback training approach produced significant short-term and long-term effects on cigarette craving and smoking behaviour, suggesting the neurofeedback protocol described herein is a promising brain-based tool for treating addiction.

Control freaks: Towards optimal selection of control conditions for fMRI neurofeedback studies.

fMRI Neurofeedback research employs many different control conditions. Currently, there is no consensus as to which control condition is best, and the answer depends on what aspects of the neurofeedback-training design one is trying to control for. These aspects can range from determining whether participants can learn to control brain activity via neurofeedback to determining whether there are clinically significant effects of the neurofeedback intervention. Lack of consensus over criteria for control conditions has hampered the design and interpretation of studies employing neurofeedback protocols. This paper presents an overview of the most commonly employed control conditions currently used in neurofeedback studies and discusses their advantages and disadvantages. Control conditions covered include no control, treatment-as-usual, bidirectional-regulation control, feedback of an alternative brain signal, sham feedback, and mental-rehearsal control. We conclude that the selection of the control condition(s) should be determined by the specific research goal of the study and best procedures that effectively control for relevant confounding factors.

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.

The Effect of Mineralocorticoid and Glucocorticoid Receptor Antagonism on Autobiographical Memory Recall and Amygdala Response to Implicit Emotional Stimuli.

BACKGROUND: Acutely elevated cortisol levels in healthy humans impair autobiographical memory recall and alter hemodynamic responses of the amygdala to emotionally valenced stimuli. It is hypothesized that the effects of the cortisol on cognition are influenced by the ratio of mineralocorticoid receptor to glucocorticoid receptor occupation. The current study examined the effects of acutely blocking mineralocorticoid receptors and glucocorticoid receptors separately on 2 processes known to be affected by altering levels of cortisol: the specificity of autobiographical memory recall, and the amygdala hemodynamic response to sad and happy faces. METHODS: We employed a within-subjects design in which 10 healthy male participants received placebo, the mineralocorticoid receptor antagonist spironolactone (600mg) alone, and the glucocorticoid receptor antagonist mifepristone (600mg) alone in a randomized, counter-balanced order separated by 1-week drug-free periods. RESULTS: On autobiographical memory testing, mineralocorticoid receptor antagonism impaired, while glucocorticoid receptor antagonism improved, recall relative to placebo, as evinced by changes in the percent of specific memories recalled. During fMRI, the amygdala hemodynamic response to masked sad faces was greater under both mineralocorticoid receptor and glucocorticoid receptor antagonism relative to placebo, while the response to masked happy faces was attenuated only during mineralocorticoid receptor antagonism relative to placebo. CONCLUSIONS: These data suggest both mineralocorticoid receptor and glucocorticoid receptor antagonism (and potentially any deviation from the normal physiological mineralocorticoid receptor/glucocorticoid receptor ratio achieved under the circadian pattern) enhances amygdala-based processing of sad stimuli and may shift the emotional processing bias away from the normative processing bias and towards the negative valence. In contrast, autobiographical memory was enhanced by conditions of reduced glucocorticoid receptor occupancy.

Kynurenine pathway metabolites are associated with hippocampal activity during autobiographical memory recall in patients with depression.

Inflammation-related changes in the concentrations of inflammatory mediators such as c-reactive protein (CRP), interleukin 1ß (IL-1), and IL-6 as well as kynurenine metabolites are associated with major depressive disorder (MDD) and affect depressive behavior, cognition, and hippocampal plasticity in animal models. We previously reported that the ratios of kynurenic acid (KynA) to the neurotoxic metabolites, 3-hydroxykynurenine (3HK) and quinolinic acid (QA), were positively correlated with hippocampal volume in depression. The hippocampus is critical for autobiographical memory (AM) recall which is impaired in MDD. Here we tested whether the ratios, KynA/3HK and KynA/QA were associated with AM recall performance as well as hippocampal activity during AM recall. Thirty-five unmedicated depressed participants and 25 healthy controls (HCs) underwent fMRI scanning while recalling emotionally-valenced AMs and provided serum samples for the quantification of kynurenine metabolites, CRP, and cytokines (IL-1 receptor antagonist - IL-1RA; IL-6, tumor necrosis factor alpha - TNF, interferon gamma -IFN-γ, IL-10). KynA/3HK and KynA/QA were lower in the MDD group relative to the HCs. The concentrations of the CRP and the cytokines did not differ significantly between the HCs and the MDD group. Depressed individuals recalled fewer specific AMs and displayed increased left hippocampal activity during the recall of positive and negative memories. KynA/3HK was inversely associated with left hippocampal activity during specific AM recall in the MDD group. Further, KynA/QA was positively correlated with percent negative specific memories recalled in the MDD group and showed a non-significant trend toward a positive correlation with percent positive specific memories recalled in HCs. In contrast, neither CRP nor the cytokines were significantly associated with AM recall or activity of the hippocampus during AM recall. Conceivably, an imbalance in levels of KynA versus QA-pathway metabolites may adversely impact the function of the hippocampus and AM recall, raising the possibility that kynurenine pathway may affect emotion-dependent memory within the context of depression.

Differential neural correlates of autobiographical memory recall in bipolar and unipolar depression.

OBJECTIVES: Autobiographical memory (AM) recall is impaired in both bipolar depression (BD) and major depressive disorder (MDD). The current study used functional magnetic resonance imaging (fMRI) to investigate differences between healthy controls (HCs) and depressed participants with either BD or MDD as they recalled AMs that varied in emotional valence. METHODS: Unmedicated adults in a current major depressive episode who met criteria for either MDD or BD and HCs (n=16/group) underwent fMRI while recalling AMs in response to emotionally valenced cue words. Control tasks involved generating examples from a given category and counting the number of risers in a letter string. RESULTS: Both participants with BD and those with MDD recalled fewer specific and more categorical memories than HC participants. During specific AM recall of positive memories, participants with BD showed increased hemodynamic activity in the ventrolateral prefrontal cortex, posterior cingulate cortex, anterior insula, middle temporal gyrus, parahippocampus, and amygdala relative to MDD and HC participants, as well as decreased dorsolateral prefrontal (DLPFC) activity relative to MDD participants. During specific AM recall of negative memories, participants with BD manifested decreased activity in the precuneus, amygdala, anterior cingulate, and DLPFC along with increased activity in the dorsomedial PFC relative to MDD participants. CONCLUSIONS: While depressed participants with BD and MDD exhibited similar depression ratings and memory deficits, the brain regions underlying successful AM recall significantly differentiated these patient groups. Differential amygdala activity during emotional memory recall (particularly increased activity in participants with BD for positive AMs) may prove useful in the differentiation of individuals with MDD and BD experiencing a depressive episode.

Contrast enhancement by combining T1- and T2-weighted structural brain MR Images.

PURPOSE: In order to more precisely differentiate cerebral structures in neuroimaging studies, a novel technique for enhancing the tissue contrast based on a combination of T1-weighted (T1w) and T2-weighted (T2w) MRI images was developed. METHODS: The combined image (CI) was calculated as CI = (T1w - sT2w)/(T1w + sT2w), where sT2w is the scaled T2-weighted image. The scaling factor was calculated to adjust the gray- matter (GM) voxel intensities in the T2w image so that their median value equaled that of the GM voxel intensities in the T1w image. The image intensity homogeneity within a tissue and the discriminability between tissues in the CI versus the separate T1w and T2w images were evaluated using the segmentation by the FMRIB Software Library (FSL) and FreeSurfer (Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital, Boston, MA) software. RESULTS: The combined image significantly improved homogeneity in the white matter (WM) and GM compared to the T1w images alone. The discriminability between WM and GM also improved significantly by applying the CI approach. Significant enhancements to the homogeneity and discriminability also were achieved in most subcortical nuclei tested, with the exception of the amygdala and the thalamus. CONCLUSION: The tissue discriminability enhancement offered by the CI potentially enables more accurate neuromorphometric analyses of brain structures.

Recall of Autobiographical Memories Following Odor vs Verbal Cues Among Adults With Major Depressive Disorder.

Importance: Major depressive disorder (MDD) is associated with deficits in autobiographical memory (AM) recall, which is thought to stem from disruptions in effortful recall. Understanding whether these deficits are mitigated when recall is stimulated more directly, such as by odor cues, could inform therapeutic interventions for MDD. Objective: To evaluate whether deficits in specific AM recall in MDD are mitigated when odor cues vs word cues are used to prompt memory. Design, Setting, and Participants: This cross-sectional study assessed recall of specific AMs in response to both odor cues and word cues (in a randomized, counterbalanced order) in a repeated measures design. Data were collected between September 2021 and November 2022. The study took place at the University of Pittsburgh School of Medicine in Pennsylvania and included adults with a primary diagnosis of MDD, according to the Mini International Neuropsychiatric Interview. Data were analyzed from January to June 2023. Main Outcomes and Measures: The primary outcome measure was the percentage of specific AMs recalled in response to odor-cued memories vs word-cued memories. Additional outcome measures included ratings of arousal, vividness, repetition, and recall response time for odor-cued memories vs word-cued memories. Results: Thirty-two adults (mean [SD] age, 30.0 [10.1] years; 26 [81.3%] female; 6 [18.8%] male) with a primary diagnosis of MDD completed the study. Participants recalled more specific AMs for odor cues than word cues (mean [SD], 68.4% [20.4%] vs 52.1% [23.3%]; Cohen d, 0.78; P < .001). Additionally, odor-cued recall was rated more arousing (mean [SD], 3.0 [0.8] vs 2.6 [0.7]; Cohen d, 1.28; P < .001) and vivid (mean [SD], 3.3 [0.7] vs 3.0 [0.7]; Cohen d, 0.67; P < .001), and was slower than word-cued recall (mean [SD], 14.5 [3.6] vs 8.9 [3.4] seconds; Cohen d, 1.18; P < .001). When compared with the population mean for word cues in healthy controls (80%), participants recalled fewer specific memories in response to words (Cohen d, 1.18; P < .001), supporting the presence of overgenerality. Notably, the percentage of specific memories recalled in response to odor cues did not differ from the healthy control population mean (Cohen d, 0.26; P = .15). Conclusions and Relevance: In this cross-sectional study, adults with MDD recalled more specific AMs in response to odor cues compared with word cues. This study suggests that AM deficits may only be observed when verbal cues are used and provides a potential new method for increasing specific AM recall in patients with MDD.

Functional neuroimaging of sex differences in autobiographical memory recall.

Autobiographical memory (AM) is episodic memory for personally experienced events. The brain areas underlying AM retrieval are known to include several prefrontal cortical and medial temporal lobe regions. Sex differences in AM recall have been reported in several behavioral studies, but the functional anatomical correlates underlying such differences remain unclear. This study used fMRI to compare the neural correlates of AM recall between healthy male and female participants (n = 20 per group). AM recall in response to positive, negative, and neutral cue words was compared to a semantic memory task involving the generation of examples from a category using emotionally valenced cues. Behaviorally, females recalled more negative and fewer positive AMs compared with males, while ratings of arousal, vividness, and memory age did not differ significantly between sexes. Males and females also did not differ significantly in their performance on control tasks. Neurophysiologically, females showed increased hemodynamic activity compared to males in the dorsolateral prefrontal cortex (DLPFC), dorsal anterior insula, and precuneus while recalling specific AMs (all valences combined); increased activity in the DLPFC, transverse temporal gyrus, and precuneus while recalling positive AMs; and increased activity in the anterior cingulate cortex, precuneus, amygdala, and temporopolar cortex when recalling negative AMs. When comparing positive to negative AMs directly, males and females differed in their BOLD responses in the hippocampus and DLPFC. We propose that the differential hemodynamic changes may reflect sex-specific cognitive strategies during recall of AMs irrespective of the phenomenological properties of those memories.

Match between cue and memory valence during autobiographical memory recall in depression.

Major depressive disorder (MDD) is associated with deficits in recalling specific autobiographical memories. The current study goal was to assess whether emotionally valenced cue words led to memories of similar emotional valence and whether this pattern differed between 12 unmedicated MDD and 14 healthy control participants. Both groups recalled autobiographical memories in response to positive, negative, and neutral cue words. Positive and neutral cues prompted recall of positive memories less often in the MDD group than in the controls. MDD participants recalled fewer specific and more categorical memories than controls; however, the proportion of specific memories didn't differ across memory valences. The MDD group had fewer specific memories in response to positive and neutral cues than the controls. These results suggest that the MDD participants may process positive stimuli differently than healthy controls and that their recall of specific autobiographical memories is impaired, regardless of the affective valence of those memories.

Low Cost MR Compatible Haptic Stimulation with Application to fMRI Neurofeedback.

The most common feedback displays in the fMRI environment are visual, e.g., in which participants try to increase or decrease the level of a thermometer. However, haptic feedback is increasingly valued in computer interaction tasks, particularly for real-time fMRI feedback. fMRI-neurofeedback is a clinical intervention that has not yet taken advantage of this trend. Here we describe a low-cost, user-friendly, MR-compatible system that can provide graded haptic vibrotactile stimulation in an initial application to fMRI neurofeedback. We also present a feasibility demonstration showing that we could successfully set up the system and obtain data in the context of a neurofeedback paradigm. We conclude that vibrotactile stimulation using this low-cost system is a viable method of feedback presentation, and encourage neurofeedback researchers to incorporate this type of feedback into their studies.

Response to SSRI intervention and amygdala activity during self-referential processing in major depressive disorder.

There are conflicting reports on the impact of antidepressants on neural reactions for positive information. We thus hypothesized that there would be clinically important individual differences in neural reactivity to positive information during SSRI therapy. We further predicted that only those who responded to SSRIs would show increased amygdala reactivity to positive information following treatment to a level similar to that seen in healthy participants. Depressed individuals (n = 17) underwent fMRI during performance of a task involving rating the self-relevance of emotionally positive and negative cue words before and after receiving 12 weeks of SSRI therapy. At post-treatment, SSRI responders (n = 11) had increased amygdala activity in response to positive stimuli, and decreased activity in response to negative stimuli, compared to non-responders (n = 6). Results suggest that normalizing amygdala responses to salient information is a correlate of SSRI efficacy. Second line interventions that modulate amygdala activity, such as fMRI neurofeedback, may be beneficial in those who do not respond to SSRI medications.

Linguistic analysis of the autobiographical memories of individuals with major depressive disorder.

BACKGROUND: Major depressive disorder (MDD) is characterized by biases in memory, attention, and cognition. The present study utilized the Linguistic Inquiry and Word Count (LIWC) to examine the content of specific autobiographical memories (AMs) recalled by individuals with MDD during an autobiographical memory task. METHODS: We examined various features of the text (including use of affective, cognitive, and self-referential terms), as well as their associations with clinical and cognitive features of MDD (depression severity, autobiographical memory specificity, amygdala activity), in 45 unmedicated adults with MDD compared to 61 healthy controls. RESULTS: When recalling positive memories MDD individuals used the word "I" less, fewer positive words, more words indicating present focus (present tense verbs), and fewer words overall to describe memories compared to controls. When recalling negative memories, MDD individuals used "I" more, more words indicating present focus, and more words overall to describe memories relative to controls. Depression severity was correlated with word count, the use of "I", and words indicating present focus in negative memories and inversely correlated with word count and the use of "I" in positive memories. Autobiographical memory specificity was correlated with word count, the use of "I", and words indicating present focus for positive memories and inversely correlated with the use of "I" and words indicating present focus for negative memories. LIMITATIONS: Due to the nature of AM recall, we could not control for the number of memories which participants recalled in each mnemonic category. CONCLUSIONS: Results align with literature implicating rumination and intensive self-focus in depression and suggest that interventions targeting specific word use may be therapeutically beneficial in the treatment of MDD.

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.

Randomized Clinical Trial of Real-Time fMRI Amygdala Neurofeedback for Major Depressive Disorder: Effects on Symptoms and Autobiographical Memory Recall.

OBJECTIVE: Patients with depression show blunted amygdala hemodynamic activity to positive stimuli, including autobiographical memories. The authors examined the therapeutic efficacy of real-time functional MRI neurofeedback (rtfMRI-nf) training aimed at increasing the amygdala's hemodynamic response to positive memories in patients with depression. METHOD: In a double-blind, placebo-controlled, randomized clinical trial, unmedicated adults with depression (N=36) were randomly assigned to receive two sessions of rtfMRI-nf either from the amygdala (N=19) or from a parietal control region not involved in emotional processing (N=17). Clinical scores and autobiographical memory performance were assessed at baseline and 1 week after the final rtfMRI-nf session. The primary outcome measure was change in score on the Montgomery-Åsberg Depression Rating Scale (MADRS), and the main analytic approach consisted of a linear mixed-model analysis. RESULTS: In participants in the experimental group, the hemodynamic response in the amygdala increased relative to their own baseline and to the control group. Twelve participants in the amygdala rtfMRI-nf group, compared with only two in the control group, had a >50% decrease in MADRS score. Six participants in the experimental group, compared with one in the control group, met conventional criteria for remission at study end, resulting in a number needed to treat of 4. In participants receiving amygdala rtfMRI-nf, the percent of positive specific memories recalled increased relative to baseline and to the control group. CONCLUSIONS: rtfMRI-nf training to increase the amygdala hemodynamic response to positive memories significantly decreased depressive symptoms and increased the percent of specific memories recalled on an autobiographical memory test. These data support a role of the amygdala in recovery from depression.

Real-Time Functional Magnetic Resonance Imaging Amygdala Neurofeedback Changes Positive Information Processing in Major Depressive Disorder.

BACKGROUND: In participants with major depressive disorder who are trained to upregulate their amygdalar hemodynamic responses during positive autobiographical memory recall with real-time functional magnetic resonance imaging neurofeedback (rtfMRI-nf) training, depressive symptoms diminish. This study tested whether amygdalar rtfMRI-nf also changes emotional processing of positive and negative stimuli in a variety of behavioral and imaging tasks. METHODS: Patients with major depressive disorder completed two rtfMRI-nf sessions (18 received amygdalar rtfMRI-nf, 16 received control parietal rtfMRI-nf). One week before and following rtfMRI-nf training, participants performed tasks measuring responses to emotionally valenced stimuli including a backward-masking task, which measures the amygdalar hemodynamic response to emotional faces presented for traditionally subliminal duration and followed by a mask, and the Emotional Test Battery in which reaction times and performance accuracy are measured during tasks involving emotional faces and words. RESULTS: During the backward-masking task, amygdalar responses increased while viewing masked happy faces but decreased to masked sad faces in the experimental versus control group following rtfMRI-nf. During the Emotional Test Battery, reaction times decreased to identification of positive faces and during self-identification with positive words and vigilance scores increased to positive faces and decreased to negative faces during the faces dot-probe task in the experimental versus control group following rtfMRI-nf. CONCLUSIONS: rtfMRI-nf training to increase the amygdalar hemodynamic response to positive memories was associated with changes in amygdalar responses to happy and sad faces and improved processing of positive stimuli during performance of the Emotional Test Battery. These results may suggest that amygdalar rtfMRI-nf training alters responses to emotional stimuli in a manner similar to antidepressant pharmacotherapy.

Amygdala Activity During Autobiographical Memory Recall in Depressed and Vulnerable Individuals: Association With Symptom Severity and Autobiographical Overgenerality.

OBJECTIVE: In healthy individuals, autobiographical memory recall is biased toward positive and away from negative events, while the opposite is found in depressed individuals. This study examined amygdala activity during autobiographical memory recall as a putative mechanism underlying biased memory recall and depressive symptoms in currently depressed adults and two vulnerable populations: individuals remitted from depression and otherwise healthy individuals at high familial risk of developing depression. Identification of such vulnerability factors could enable interception strategies that prevent depression onset. METHOD: Sixty healthy control subjects, 45 unmedicated currently depressed individuals, 25 unmedicated remitted depressed individuals, and 30 individuals at high familial risk of developing depression underwent functional MRI while recalling autobiographical memories in response to emotionally valenced cue words. Amygdala reactivity and connectivity with anatomically defined amygdala regions were examined. RESULTS: During positive recall, depressed participants exhibited significantly decreased left amygdala activity and decreased connectivity with regions of the salience network compared with the other groups. During negative recall, control subjects had significantly decreased left amygdala activity compared with the other groups, while depressed participants exhibited increased amygdala connectivity with the salience network. In depressed participants, left amygdala activity during positive recall correlated significantly with depression severity (r values >-0.38) and percent of positive specific memories recalled (r values >0.59). CONCLUSIONS: The results suggest that left amygdala hyperactivity during negative autobiographical recall is a trait-like marker of depression, as both vulnerable groups showed activity similar to the depressed group, while amygdala hypoactivity during positive autobiographical recall is a state marker of depression manifesting in active disease. Treatments targeting amygdala hypoactivity and blunted salience during positive autobiographical recall could exert antidepressant effects.