Increased Amygdala Activations during the Emotional Experience of Death-Related Pictures in Complicated Grief: An fMRI Study

The effects of social loss and isolation on partner odor investigation and dopamine and oxytocin receptor expression in female prairie voles

In humans, grief is characterized by intense sadness, intrusive thoughts of the deceased, and intense longing for reunion with the deceased. Human fMRI studies show hyperactivity in emotional pain and motivational centers of the brain when an individual is reminded of a deceased attachment figure, but the molecular underpinnings of these changes in activity are unknown. Prairie voles (Microtus ochrogaster), which establish lifelong social bonds between breeding pairs, also display distress and motivational shifts during periods of prolonged social loss, providing a model to investigate these behavioral and molecular changes at a mechanistic level. Here, a novel odor preference test was used to assess social vs non-social odor investigation, and a sucrose preference test was used to assess non-social, reward-driven motivation. Females that lost a male partner investigated partner- and food-associated cues significantly more than females that lost a female cagemate or remained intact with a male partner. However, females experiencing the loss of a male partner did not change investigation of stranger-associated cues. Western blotting revealed significant increases of dopamine receptor type 1 (DRD1) and oxytocin receptor protein content in specific brain regions in response to the loss of distinct social relationships. Such effects included an increase in DRD1 in the medial preoptic area of the hypothalamus (mPOA) in females experiencing loss of a male partner compared to all other conditions. Pharmacological antagonism of DRD1 in the mPOA blocked the loss-associated increase of investigation of the partner odor but did not affect investigation of food or stranger odors. This reveals a novel dopamine-mediated mechanism for partner-seeking behavior during periods of partner loss in female prairie voles.

Amygdala-Centered Emotional Processing in Prolonged Grief Disorder: Relationship With Clinical Symptomatology

BACKGROUND

Prolonged grief disorder (PGD) is a multidimensional condition with adverse health consequences. We hypothesized that enhanced negative emotional bias characterizes this disorder and underlies its key clinical symptoms.

METHODS

In a cross-sectional design, chronically grieving older adults (age 61.5 ± 8.9 years) experiencing probable PGD (n = 33) were compared with demographic- and time since loss-equated integrated (adaptive) grief participants (n = 38). To probe generalized negative affective reactivity, participants performed an emotional face-matching task during functional magnetic resonance imaging scanning and completed demographic and clinical assessments. Contrast maps (fearful + angry faces [-] shapes) were generated to determine group differences in brain activity within hypothesized affective and regulatory processing regions (amygdala, anterior insula, dorsal anterior cingulate, dorsolateral prefrontal cortex) and in exploratory whole-brain regression analyses.

RESULTS

The PGD group showed higher right amygdala activation to negative emotional stimuli than the integrated grief group (pcorrected < .05), which positively correlated with intrusive thoughts. Generalized psychophysiological interaction analysis revealed lower task-dependent functional connectivity (FC) between the right amygdala and posterior cingulate cortex/precuneus in PGD (pcorrected < .05), which negatively correlated with avoidance of loss reminders. Resting-state FC between the identified right amygdala and thalamus was higher in PGD (pcorrected < .05), which negatively correlated with loneliness.

CONCLUSIONS

Dysregulated amygdala-centric neural activity and FC during processing of negative affective stimuli and at rest appear to differentiate prolonged from integrated grief in older adults. Future investigations that use interventions to target amygdala-centric neural circuit abnormalities may provide new insights into the role of enhanced negative bias and related mechanisms that underlie PGD and support treatment efficacy.

Atrophy in the supramarginal gyrus associated with impaired cognitive inhibition in grieving Chinese Shidu parents

Background: The loss of an only child, known as Shidu in China, is a profoundly distressing experience, often leading to Prolonged Grief Disorder (PGD). Despite its impact, the structural brain alterations associated with PGD, potentially influencing cognitive impairments in Shidu parents, remain understudied.Objective: This study aims to identify brain structural abnormalities related to prolonged grief and their relation with cognitive inhibition in Shidu parents.Methods: The study included 40 Shidu parents and 42 non-bereaved participants. Prolonged grief was evaluated using the Prolonged Grief Questionnaire (PG-13). We employed voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) to assess brain structural alterations and their correlation with cognitive inhibition, as measured by Stroop interference scores.Results: Findings suggest that greater prolonged grief intensity correlates with reduced grey matter volume in the right amygdala and the left supramarginal gyrus (SMG). Additionally, enhanced amygdala-to-whole-brain structural connectivity showed a marginal association with prolonged grief, particularly with emotional-related symptoms. Furthermore, a decrease in SMG volume was found to mediate the relation between prolonged grief and Stroop Time Inference (TI) score, indicating an indirect effect of prolonged grief on cognitive inhibition.Conclusions: The study provides insight into the neural correlates of prolonged grief in Shidu parents, highlighting the SMG's role in cognitive inhibition. These findings emphasise the need for comprehensive grief interventions to address the complex cognitive and emotional challenges faced by this unique bereaved population.

From love to pain: is oxytocin the key to grief complications?

While most adults confronted with the death of a loved one manage to grieve, about 10-20% of individuals develop complicated grief, characterized by persistent distress and impaired social skills, or pathological grief, defined by the onset or decompensation of a psychiatric disorder. Little is known about the biological causes of these grief complications. Recent work suggests that oxytocin, a major neuroendocrine hormone regulating many neurocognitive mechanisms, may be involved in this process. Oxytocin is widely studied and well known for its impact on the mother-child bond and hormonal and brain systems related to attachment and social interactions. In this article, we propose a neurocognitive model of grief complications based on existing data on the role of oxytocin in interpersonal attachment and its impact on brain activity. We suggest that complicated grief is associated with dysfunctional cerebral oxytocinergic signaling and persistent hyperactivation of the nucleus accumbens. This mechanism is involved in limiting the reduction of interpersonal attachment to the deceased during acute phases and in searching for new interpersonal relationships during the recovery phase. We show how the exploration of cerebral oxytocinergic signaling would improve the understanding of physiological grief mechanisms in the general population and could allow the development of new therapeutic perspectives against the complications of grief.

A Systematic Review of MRI Studies and the "Emotional paiN and social Disconnect (END)" Brain Model of Suicidal Behavior in Youth

Introduction

Risk of suicidal ideation and suicidal behaviors greatly increases during adolescence, and rates have risen dramatically over the past two decades. However, few risk factors or biomarkers predictive of suicidal ideation or attempted suicide have been identified in adolescents. Neuroimaging correlates hold potential for early identification of adolescents at increased risk of suicidality and risk stratification for those at high risk of suicide attempt.

Methods

In this systematic review, we evaluated neural regions and networks associated with suicidal ideation and suicide attempt in adolescents derived from magnetic resonance imaging (MRI) studies. A total of 28 articles were included in this review.

Results

After descriptively synthesizing the literature, we propose the Emotional paiN and social Disconnect (END) model of adolescent suicidality and present two key neural circuits: (1) the emotional/mental pain circuit and (2) the social disconnect/distortion circuit. In the END model, the emotional pain circuit-consisting of the cerebellum, amygdala, and hippocampus-shows similar aberrations in adolescents with suicidal ideation as in those with a history of a suicide attempt (but to a smaller degree). The social disconnect circuit is unique to adolescent suicide attempters and includes the lateral orbitofrontal cortex (OFC), the temporal gyri, and the connections between them.

Conclusion

Our proposed END brain model of suicidal behavior in youth, if confirmed by future prospective studies, can have implications for clinical goals of early detection, risk stratification, and intervention development. Treatments that target emotional pain and social disconnect may be ideal interventions for reducing suicidality in adolescents.

Ventral striatal subregional dysfunction in late-life grief: Relationships with yearning and depressive symptoms

Bereaved older adults experiencing high grief in the first year after an attachment loss is at increased risk for prolonged grief disorder (PGD) via unknown mechanisms. Yearning, a core grief symptom, is linked to the ventral striatal (VS) brain function, but the role of this neuronal system in late-life grief is poorly understood. As a first step, we examined the VS subregional abnormalities associated with multidimensional symptoms in bereaved elders during the first year post-loss. Sixty-five bereaved elders completed clinical assessments within 13 months post-loss. Ventral caudate (VCau) and nucleus accumbens (NAcc) functional connectivity (FC) was assessed using seed-based resting-state functional MRI. VCau and NAcc FC differences between high (inventory of complicated grief [ICG] score≥30; n = 35) and low (ICG score<30; n = 30) grief, and the relationships between ventral striatal subregional FC and clinical measures (yearning and depressive symptoms) were assessed after covariate adjustments (α < 0.05; 3dClustSim corrected). Relative to low grief participants, those with high grief showed higher FC between VCau and the medial prefrontal, orbitofrontal, and subgenual cingulate cortices. VCau FC abnormalities positively correlated with yearning (r2 = 0.24, p < 0.001). In contrast, FC between VCau and temporoparietal junction negatively correlated with depressive symptoms, a commonly co-occurring symptom (r2 = 0.37, p < 0.001). The FC between NAcc and insula/striatum positively correlated with yearning (r2 = 0.35, p < 0.001); no other NAcc FC findings were seen in the full sample. In women, higher FC between the NAcc and bilateral posterior cingulate, precuneus, and visual areas were found in those with high, relative to low grief symptoms. Distinct VS subregional abnormalities associate with yearning and depressive symptoms in bereaved elders. Whether ventral striatal dysfunction correlates with PGD development and/or worsening depression remains to be elucidated.

Interactions between the κ opioid system, corticotropin-releasing hormone and oxytocin in partner loss

Selective adult social attachments, or ‘pair bonds’, represent central relationships for individuals in a number of social species, including humans. Loss of a pair mate has emotional consequences that may or may not diminish over time, and that often translate into impaired psychological and physical health. In this paper, we review the literature on the neuroendocrine mechanisms for the emotional consequences of partner loss, with a special focus on hypothesized interactions between oxytocin, corticotropin-releasing hormone and the κ opioid system.

This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.

Emerging experience with selected new categories in the ICD-11: complex PTSD, prolonged grief disorder, gaming disorder, and compulsive sexual behaviour disorder

Among the important changes in the ICD-11 is the addition of 21 new mental disorders. New categories are typically proposed to: a) improve the usefulness of morbidity statistics; b) facilitate recognition of a clinically important but poorly classified mental disorder in order to provide appropriate management; and c) stimulate research into more effective treatments. Given the major implications for the field and for World Health Organization (WHO) member states, it is important to examine the impact of these new categories during the early phase of the ICD-11 implementation. This paper focuses on four disorders: complex post-traumatic stress disorder, prolonged grief disorder, gaming disorder, and compulsive sexual behaviour disorder. These categories were selected because they have been the focus of considerable activity and/or controversy and because their inclusion in the ICD-11 represents a different decision than was made for the DSM-5. The lead authors invited experts on each of these disorders to provide insight into why it was considered important to add it to the ICD-11, implications for care of not having that diagnostic category, important controversies about adding the disorder, and a review of the evidence generated and other developments related to the category since the WHO signaled its intention to include it in the ICD-11. Each of the four diagnostic categories appears to describe a population with clinically important and distinctive features that had previously gone unrecognized as well as specific treatment needs that would otherwise likely go unmet. The introduction of these categories in the ICD-11 has been followed by a substantial expansion of research in each area, which has generally supported their validity and utility, and by a significant increase in the availability of appropriate services.

Why do mothers never stop grieving for their deceased children? Enduring alterations of brain connectivity and function

A child's death is a profound loss for mothers and affects hundreds of thousands of women. Mothers report inconsolable and progressive grief that is distinct from depression and impacts daily emotions and functions. The brain mechanisms responsible for this relatively common and profound mental health problem are unclear, hampering its clinical recognition and care. In an initial exploration of this condition, we used resting state functional MRI (fMRI) scans to examine functional connectivity in key circuits, and task-based fMRI to examine brain network activity in grieving mothers in response to pictures of their deceased child and as well as recognizable deceased celebrities and unfamiliar individuals. We compared nine mothers who had lost an adult child and aged-matched control mothers with a living child of a similar age. Additionally, we collected diffusion imaging scans to probe structural connectivity and complemented the imaging studies with neuropsychological assessments. Increased functional activation in Ventral Attention/Salience Networks accompanied by a reduced activation in the medial prefrontal cortex in response to the deceased child's picture robustly distinguished the grieving mothers from controls. Heightened resting-state functional connectivity between the paraventricular thalamic nucleus (PVT) and the amygdala distinguished the grieving mothers from the controls and correlated with subjective grief severity. Structurally, maternal grief and its severity were associated with alterations in corticolimbic white matter tracts. Finally, grieving mothers performed worse than controls on neuropsychological tests of learning, memory, and executive function, linked with grief severity. Reduced activation in cortical regions inhibiting emotions and changes in the PVT circuitry-a region involved in long-term emotional memories and decision making under conflict-distinguish grieving mothers from controls. Notably, the magnitude of neurobiological changes correlates with the subjective severity of grief. Together, these new discoveries delineate a prevalent and under-recognized mental health syndrome and chart a path for its appreciation and care.

Neuropsychological Comparison of Guilt and Grief: A Review of Guilt Aspects in Prolonged Grief Disorder

Taking an integrative approach toward developmental psychology and neurophysiology, this review selects findings from the psychological and medical literature on guilt and bereavement that are relevant to considering whether and how guilt contributes to the development of prolonged grief disorder (PGD) in bereaved persons. Mention of guilt is ubiquitous in literature on general grief and PGD, including 54 articles related to the neuropsychological development and manifestations of guilt and grief, as well as their neuroimaging correlates, that met scoping review criteria. However, mechanisms connecting guilt to development of PGD are scarce. Aspects of guilt are conceptually connected to many PGD criteria, opening avenues to explore treatment of PGD by targeting guilt. Positive and prosocial aspects of guilt are especially neglected in the treatment of psychiatric disorders, and consideration of these aspects may improve interventions for PGD such as complicated grief treatment.

The neurobiological reward system in Prolonged Grief Disorder (PGD): A systematic review

Prolonged Grief Disorder (PGD) is a debilitating condition affecting between 7% and 10% of bereaved individuals. Past imaging and psychological studies have proposed links between PGD's characteristic symptoms - in particular, profound yearning - and the neural reward system. We conducted a systematic review to investigate this connection. On December 19, 2019, we searched six bibliographic databases for data on the neurobiology of grief and disordered grief. We excluded studies of the hypothalamic-pituitary-adrenal (HPA) axis, animal studies, and reviews. After abstract and full-text screening, twenty-four studies were included in the final review. We found diverse evidence for the activation of several reward-related regions of the brain in PGD. The data reviewed suggest that compared to normative grief, PGD involves a differential pattern of activity in the amygdala and orbitofrontal cortex (OFC); likely differential activity in the posterior cingulate cortex (PCC), rostral or subgenual anterior cingulate cortex (ACC), and basal ganglia overall, including the nucleus accumbens (NAc); and possible differential activity in the insula. It also appears that oxytocin signaling is altered in PGD, though the exact mechanism is unclear. Our findings appear to be consistent with, though not confirmative of, conceptualizing PGD as a disorder of reward, and identify directions for future research.