Strengthened Hippocampal Circuits Underlie Enhanced Retrieval of Extinguished Fear Memories Following Mindfulness Training

Beneficial effects of mindfulness-based intervention on hippocampal volumes and episodic memory for childhood adversity survivors

Background

Adverse Childhood Experience (ACE) has detrimental impacts on neural development, especially hippocampal morphometry. Mindfulness-Based Interventions (MBI) has been shown to induce adaptive hippocampal changes especially at the subiculum. The present study aims to investigate the effects of MBI on subiculum volumes among ACE survivors, as well as the effects on episodic memory as a probe into hippocampal functionality.

Methods

We analyzed anatomical MRI data and performance indices from an episodic memory task called the Mnemonic Similarity Task (MST) collected from a randomized controlled longitudinal study that compared an 8-week MBI (N = 20) to an active control condition of Stress Management Education (SME) (N = 19). FreeSurfer 6.0 was used for automated hippocampal subfield segmentation and volumetric estimation.

Results

Significant group differences were observed with the volumetric changes of the right whole hippocampus and right subiculum. Only the MBI group showed improved pattern separation capability from MST, which was associated with stress reduction and right subiculum volumetric changes.

Limitations

Modest sample size. MST task was performed outside of MRI.

Conclusions

These findings suggest beneficial effects of MBI for hippocampal volumes and episodic memory, while highlighting the importance of the subiculum for MBI-induced neural and cognitive changes. The subiculum's known role in inhibitory control was interpreted as a potential mechanism for it to exhibit MBI-induced volumetric changes, which sheds light on the potential neural underpinnings of mindfulness meditation for reducing stress reactivity among ACE survivors.

Distributed neural representations of conditioned threat in the human brain

Detecting and responding to threat engages several neural nodes including the amygdala, hippocampus, insular cortex, and medial prefrontal cortices. Recent propositions call for the integration of more distributed neural nodes that process sensory and cognitive facets related to threat. Integrative, sensitive, and reproducible distributed neural decoders for the detection and response to threat and safety have yet to be established. We combine functional MRI data across varying threat conditioning and negative affect paradigms from 1465 participants with multivariate pattern analysis to investigate distributed neural representations of threat and safety. The trained decoders sensitively and specifically distinguish between threat and safety cues across multiple datasets. We further show that many neural nodes dynamically shift representations between threat and safety. Our results establish reproducible decoders that integrate neural circuits, merging the well-characterized 'threat circuit' with sensory and cognitive nodes, discriminating threat from safety regardless of experimental designs or data acquisition parameters.

Mindfulness training and exercise differentially impact fear extinction neurocircuitry

BACKGROUND

The ability to extinguish a maladaptive conditioned fear response is crucial for healthy emotional processing and resiliency to aversive experiences. Therefore, enhancing fear extinction learning has immense potential emotional and health benefits. Mindfulness training enhances both fear conditioning and recall of extinguished fear; however, its effects on fear extinction learning are unknown. Here we investigated the impact of mindfulness training on brain mechanisms associated with fear-extinction learning, compared to an exercise-based program.

METHODS

We investigated BOLD activations in response to a previously learned fear-inducing cue during an extinction paradigm, before and after an 8-week mindfulness-based stress reduction program (MBSR, n = 49) or exercise-based stress management education program (n = 27).

RESULTS

The groups exhibited similar reductions in stress, but the MBSR group was uniquely associated with enhanced activation of salience network nodes and increased hippocampal engagement.

CONCLUSIONS

Our results suggest that mindfulness training increases attention to anticipatory aversive stimuli, which in turn facilitates decreased aversive subjective responses and enhanced reappraisal of the memory.

Neural correlates of mindfulness meditation and hypnosis on magnetic resonance imaging: similarities and differences. A scoping review

BACKGROUND

Mindfulness meditation (MM) and hypnosis practices are gaining interest in mental health, but their physiological mechanisms remain poorly understood. This study aimed to synthesize the functional, morphometric and metabolic changes associated with each practice using magnetic resonance imaging (MRI), and to identify their similarities and differences.

METHODS

MRI studies investigating MM and hypnosis in mental health, specifically stress, anxiety, and depression, were systematically screened following PRISMA guidelines from four research databases (PubMed, Web of Science, Embase, PsycINFO) between 2010 and 2022.

RESULTS

In total, 97 references met the inclusion criteria (84 for MM and 13 for hypnosis). This review showed common and divergent points regarding the regions involved and associated brain connectivity during MM practice and hypnosis. The primary commonality between mindfulness and hypnosis was decreased default mode network intrinsic activity and increased central executive network - salience network connectivity. Increased connectivity between the default mode network and the salience network was observed in meditative practice and mindfulness predisposition, but not in hypnosis.

CONCLUSIONS

While MRI studies provide a better understanding of the neural basis of hypnosis and meditation, this review underscores the need for more rigorous studies.

Smaller Hippocampal Volume Is Associated With Reduced Posttraumatic Stress Symptoms in Children With Cancer and Survivors Following a Brief Novel Martial Arts-Based Intervention

PURPOSE

Children with cancer and survivors frequently report posttraumatic stress symptoms (PTSS), which are associated with volumetric changes in stress-sensitive brain regions, including the hippocampus.

METHODS

We examined the impact of a novel, 4-week martial-arts-based meditative intervention on cancer-related PTSS in 18 pediatric patients and survivors and whether baseline hippocampal volumes correlate with PTSS severity and/or PTSS changes over time.

RESULTS

Overall, PTSS did not significantly change from baseline to post-intervention. Smaller hippocampal volume was correlated with more severe re-experiencing PTSS at baseline, and greater reductions in PTSS post-intervention.

CONCLUSIONS

Together, hippocampal volume may be a biomarker of PTSS severity and intervention response. Identifying hippocampal volume as a potential biomarker for PTSS severity and intervention response may allow for more informed psychosocial treatments.

Optimizing the Implementation of a Lifestyle Dementia Prevention Intervention for Older Patients in an Academic Healthcare System

Background

Interventions that promote healthy lifestyles are critical for the prevention of Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD). However, knowledge of the best practices for implementing AD/ADRD prevention in healthcare settings remains limited.

Objective

We aimed to qualitatively identify barriers and facilitators to implementing a clinical trial of a novel lifestyle intervention (My Healthy Brain) in our medical center for older patients with subjective cognitive decline who are at-risk for AD/ADRD.

Methods

We conducted focus groups with 26 healthcare professionals (e.g., physicians, psychology, nursing) from 5 clinics that treat older patients (e.g., memory care, psychiatry). Our qualitative analysis integrated two implementation frameworks to systematically capture barriers and facilitators to AD/ADRD prevention (Consolidated Framework for Implementation Science Research) that impact implementation outcomes of acceptability, appropriateness, and feasibility (Proctor's framework).

Results

We found widespread support for an RCT of My Healthy Brain and AD/ADRD prevention. Participants identified barriers related to patients (stigma, technological skills), providers (dismissiveness of "worried well," doubting capacity for behavior change), clinics (limited time and resources), and the larger healthcare system (underemphasis on prevention). Implementation strategies guided by Expert Recommendations for Implementing Change (ERIC) included: developing tailored materials, training staff, obtaining buy-in from leadership, addressing stigmatized language and practices, identifying "champions," and integrating with workflows and resources.

Conclusions

The results will inform our recruitment, enrollment, and retention procedures to implement the first randomized clinical trial of My Healthy Brain. Our study provides a blueprint for addressing multi-level barriers to the implementation of AD/ADRD prevention for older patients in medical settings.

Childhood adversity severity modulates the associations between adaptive psychological changes and amygdala volumetric changes in response to behavioral interventions

Background

Adverse Childhood Experience (ACE) has been shown to have detrimental impact on amygdala structure. Prior research found that adaptive psychological changes after Mindfulness-Based Interventions (MBI) were associated with amygdala volumetric changes. The present study aims to further investigate whether such effects also occur among ACE survivors and whether the effects are unique to MBI.

Methods

A total of 64 young adult childhood adversity survivors were randomized to an eight-week MBI or Stress Management Education (SME) as an active control condition. Anatomical MRI and questionnaires on mindfulness, stress and psychological health were collected at baseline and post-intervention. Due to subject dropout, the final sample included 39 subjects (MBI:20, SME:19).

Results

Both groups showed increased mindfulness levels, reduced stress, and improved psychological symptoms (depression, anxiety, and somatization), with no significant group by time interaction effect. There was no significant group difference on amygdala volumetric changes. Within the MBI group, childhood maltreatment severity was a significant mediator between changes of mindfulness levels and right amygdala volumetric changes. Across pooled sample of both groups, childhood maltreatment was a significant moderator for the effect of trait anxiety level changes on left amygdala volumetric changes.

Limitations

Modest sample size, relatively low retention rates, suboptimal monitoring of home practice.

Conclusions

MBI did not demonstrate overall better clinical effects than SME. Psychological-change-dependent amygdala volumetric change was not specific to MBI. Childhood maltreatment severity modulated the relationships between adaptive psychological changes and amygdala volumetric changes.

Effects of web-based mindfulness training on psychological outcomes, attention, and neuroplasticity

Mindfulness meditation training (MMT) reliably reduces stress and anxiety while also improving attention. The primary aim of this study was to investigate the relationship between MMT, stress and anxiety reduction, and its impact upon improvements in attention on the behavioral and neuronal levels. As a second aim, we sought to explore any relationship between MMT, attention, and modified states of mind such as flow. 118 healthy, meditation-naïve, participants were either assigned to a 31-day, web-based, MMT or an active control, health training (HT). Participants underwent functional magnetic resonance imaging while performing the attention network test (ANT) to assess functional and behavioural attentional changes, diffusion tensor imaging (DTI) to assess microstructural neuronal changes and completed relevant questionnaires to explore changes in psychological outcomes. Results confirmed a reduction in perceived stress and anxiety levels in the MMT group and significant improvements in the overall reaction time during the ANT, albeit no specific effects on the attentional components were observed. No statistically significant changes were found in the HT group. Interestingly, a significant group-by-time interaction was seen in flow experience. Functional data exhibited an increased activity in the superior frontal gyrus, posterior cingulate cortex, and right hippocampus during the alerting condition of the ANT after the MMT; decreased stress and trait anxiety were significantly correlated with the activation in the right hippocampus, and increased flow was also significantly correlated with all the aforementioned areas. DTI data showed increased fractional anisotropy values in the right uncinate fasciculus indicating white matter microarchitecture improvement between the right hippocampus and frontal areas of the brain. This study, therefore, demonstrates the effectiveness of web-based MMT on overall well-being and attentional performance, while also providing insight into the relationship between psychological outcomes, attention, and neuroplastic changes.

Within-Person Modulation of Neural Networks following Interoceptive Awareness Training through Mindful Awareness in Body-Oriented Therapy (MABT): A Pilot Study

Interoception, the representation of the body's internal state, is increasingly recognized for informing subjective wellbeing and promoting regulatory behavior. However, few empirical reports characterize interoceptive neural networks, and fewer demonstrate changes to these networks in response to an efficacious intervention. Using a two-group randomized controlled trial, this pilot study explored within-participant neural plasticity in interoceptive networks following Mindful Awareness in Body-oriented Therapy (MABT). Participants (N = 22) were assigned to either 8 weeks of MABT or to a no-treatment control and completed baseline and post-intervention assessments that included subjective interoceptive awareness (MAIA) and neuroimaging of an interoceptive awareness task. MABT was uniquely associated with insula deactivation, increased functional connectivity between the dorsal attention network and the somatomotor cortex, and connectivity changes correlated positively with changes in subjective interoception. Within the MABT group, changes in subjective interoception interacted with changes in a predefined anterior cingulate seed region to predict changes in right middle insula activity, a putative primary interoceptive representation region. While the small sample size requires the replication of findings, results suggest that interoceptive training enhances sensory-prefrontal connectivity, and that such changes are commensurate with enhanced interoceptive awareness.

The Missing Ingredient: How Misogyny and the Patriarchy Sabotage our Clinical Practice and Research

Discussing massive, unrelenting trauma, especially during a global pandemic, when the threat is not only personally affecting you, but also everyone else, is not an easy thing to do. We can see the consequences of two years of being locked inside. People's trauma responses literally came flooding out. It seems that the pandemic tipped us over an abyss that is hard to comprehend. In so many countries there are protests, laws rolling back basic human rights, the threat of fascism, and actual war. There seems to be widespread governmental corruption that cannot stop the favouritism of those who have wealth, and perpetually admonish those who do not. Our world seems very unstable. Change is deeply desired. Yet, this instability is predictable. It is predictable because the systems that created the structures that "run and rule" us are fundamentally destructive and violent. In never-ending ways, the only way that change happens is by utilizing violence as the only way to achieve change. This is the legacy of patriarchy. A system that not only is ruled by one group of people but also tends to be controlled by a very specific type of person. It is a system that cultivates human cruelty, selfishness, and violence. It is a system that is managed by those who do the "best" in violence. Most of us do not work this way but are forced to live this way because of the belief that humans are innately violent, selfish, and self-serving; a myth based on the traumatic reaction of fight. It is a dissociated, relational injury that is a direct result of not having our mothers and fathers able to be mothers and fathers. It is formed in misogyny. There are ways to heal, if one can comprehend what misogyny does to human beings, and what we would be like in its absence.

Interoception in Fear Learning and Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a psychiatric condition characterized by sustained symptoms, including reexperiencing, hyperarousal, avoidance, and mood alterations, following exposure to a traumatic event. Although symptom presentations in PTSD are heterogeneous and incompletely understood, they likely involve interactions between neural circuits involved in memory and fear learning and multiple body systems involved in threat processing. PTSD differs from other psychiatric conditions in that it is a temporally specific disorder, triggered by a traumatic event that elicits heightened physiological arousal, and fear. Fear conditioning and fear extinction learning have been studied extensively in relation to PTSD, because of their central role in the development and maintenance of threat-related associations. Interoception, the process by which organisms sense, interpret, and integrate their internal body signals, may contribute to disrupted fear learning and to the varied symptom presentations of PTSD in humans. In this review, the authors discuss how interoceptive signals may serve as unconditioned responses to trauma that subsequently serve as conditioned stimuli, trigger avoidance and higher-order conditioning of other stimuli associated with these interoceptive signals, and constitute an important aspect of the fear learning context, thus influencing the specificity versus generalization of fear acquisition, consolidation, and extinction. The authors conclude by identifying avenues for future research to enhance understanding of PTSD and the role of interoceptive signals in fear learning and in the development, maintenance, and treatment of PTSD.

Detection of neuronal defensive discharge information transmission and characteristics in periaqueductal gray double-subregions using PtNP/PEDOT:PSS modified microelectrode arrays

Threatened animals respond with appropriate defensive behaviors to survive. It has been accepted that midbrain periaqueductal gray (PAG) plays an essential role in the circuitry system and organizes defensive behavioral responses. However, the role and correlation of different PAG subregions in the expression of different defensive behaviors remain largely unexplored. Here, we designed and manufactured a microelectrode array (MEA) to simultaneously detect the activities of dPAG and vPAG neurons in freely behaving rats. To improve the detection performance of the MEAs, PtNP/PEDOT:PSS nanocomposites were modified onto the MEAs. Subsequently, the predator odor was used to induce the rat's innate fear, and the changes and information transmission in neuronal activities were detected in the dPAG and vPAG. Our results showed that the dPAG and vPAG participated in innate fear, but the activation degree was distinct in different defense behaviors. During flight, neuronal responses were stronger and earlier in the dPAG than the vPAG, while vPAG neurons responded more strongly during freezing. By applying high-performance MEA, it was revealed that neural information spread from the activated dPAG to the weakly activated vPAG. Our research also revealed that dPAG and vPAG neurons exhibited different defensive discharge characteristics, and dPAG neurons participated in the regulation of defense responses with burst-firing patterns. The slow activation and continuous firing of vPAG neurons cooresponded with the regulation of long-term freezing responses. The results demonstrated the important role of PAG neuronal activities in controlling different aspects of defensive behaviors and provided novel insights for investigating defense from the electrophysiological perspective.

Inhibitory circuits in fear memory and fear-related disorders

Fear learning and memory rely on dynamic interactions between the excitatory and inhibitory neuronal populations that make up the prefrontal cortical, amygdala, and hippocampal circuits. Whereas inhibition of excitatory principal cells (PCs) by GABAergic neurons restrains their excitation, inhibition of GABAergic neurons promotes the excitation of PCs through a process called disinhibition. Specifically, GABAergic interneurons that express parvalbumin (PV+) and somatostatin (SOM+) provide inhibition to different subcellular domains of PCs, whereas those that express the vasoactive intestinal polypeptide (VIP+) facilitate disinhibition of PCs by inhibiting PV+ and SOM+ interneurons. Importantly, although the main connectivity motifs and the underlying network functions of PV+, SOM+, and VIP+ interneurons are replicated across cortical and limbic areas, these inhibitory populations play region-specific roles in fear learning and memory. Here, we provide an overview of the fear processing in the amygdala, hippocampus, and prefrontal cortex based on the evidence obtained in human and animal studies. Moreover, focusing on recent findings obtained using genetically defined imaging and intervention strategies, we discuss the population-specific functions of PV+, SOM+, and VIP+ interneurons in fear circuits. Last, we review current insights that integrate the region-specific inhibitory and disinhibitory network patterns into fear memory acquisition and fear-related disorders.

Meditation Using a Mobile App Improves Surgery Trainee Performance: a simulation-based randomized controlled trial

PURPOSE

To primarily investigate: (1) whether a 10 min instant meditation practice using mobile app could enhance arthroscopy performance and (2) whether a 10-day app-based meditation could reduce short-term arthroscopic skills deterioration.

METHODS

Orthopedic residents with no previous experience in arthroscopy and meditation were randomly assigned to Groups A, B, and C. After initial standard competency-based arthroscopy training on the simulator on Day 1, a pretest was performed via simulator by all participants to assess their initial level of performance, then Groups A and B were required to practice app-based mindfulness meditation 10 min/day for 10 consecutive days, while Group C did nothing. On Day 11, all participants came back to perform a posttest. Prior to the posttest, the participants in Group A practiced app-based meditation (10 min) , whereas Groups B and C had no intervention.

RESULTS

43 participants were included and reached similar level of performance after initial training phase in Day1. In Day11, participants in Group A had statistically better instant arthroscopy performance than Group B, with higher total score (Mean Difference, 3.57; P<.001), less completion time (MD, -42.89s; P=.001), shorter camera (MD, -23.38cm; P<.001) and grasper (MD, -15.23cm; P=.002) path length and less cartilage injury (MD, -1.07%; P=.012). Participants in Group B had less skills deterioration than Group C, with better total score (MD, -5.42; P<.001), less completion time (MD, 51.96s; P=.002), camera path length (MD, 28.41cm; P=.007) and cartilage injury (MD, 1.19%; P=.038).

CONCLUSION

Meditation training using mobile app enhanced instant simulation-based arthroscopy performance and reduced short-term skills deterioration of orthopedic residents with no arthroscopy hands-on experience.

CLINICAL RELEVANCE

Meditation using mobile app for clinicians and educators should be incorporated into simulation-based arthroscopy curriculums and perhaps clinical settings to improve arthroscopy performance and mental health of orthopedic residents without any prior arthroscopy experience.

Underlying mechanisms of mindfulness meditation: Genomics, circuits, and networks

Understanding neuropsychological mechanisms of mindfulness meditation (MM) has been a hot topic in recent years. This review was conducted with the goal of synthesizing empirical relationships via the genomics, circuits and networks between MM and mental disorders. We describe progress made in assessing the effects of MM on gene expression in immune cells, with particular focus on stress-related inflammatory markers and associated biological pathways. We then focus on key brain circuits associated with mindfulness practices and effects on symptoms of mental disorders, and expand our discussion to identify three key brain networks associated with mindfulness practices including default mode network, central executive network, and salience network. More research efforts need to be devoted into identifying underlying neuropsychological mechanisms of MM on how it alleviates the symptoms of mental disorders.

Top-down threat bias in pain perception is predicted by intrinsic structural and functional connections of the brain

Top-down processes such as expectations play a key role in pain perception. In specific contexts, inferred threat of impending pain can affect perceived pain more than the noxious intensity. This biasing effect of top-down threats can affect some individuals more strongly than others due to differences in fear of pain. The specific characteristics of intrinsic brain characteristics that mediate the effects of top-down threat bias are mainly unknown. In this study, we examined whether threat bias is associated with structural and functional brain connectivity. The variability in the top-down bias was mapped to the microstructure of white matter in diffusion weighted images (DWI) using MRTrix3. Mean functional connectivity of five canonical resting state networks was tested for association with bias scores and with the identified DWI metrics. We found that the fiber density of the splenium of the corpus callosum was significantly low in individuals with high top-down threat bias (FWE corrected with 5000 permutations, p < 0.05). The mean functional connectivity within the language/memory and between language/memory and default mode networks predicted the bias scores. Functional connectivity within language memory networks predicted the splenium fiber density, higher pain catastrophizing and lower mindful awareness. Probabilistic tractography showed that the identified region in the splenium connected several sensory regions and high-order parietal regions between the two hemispheres, indicating the splenium's role in sensory integration. These findings demonstrate that individuals who show more change in pain with changes in the threat of receiving a stronger noxious stimulus have lower structural connectivity in the pathway necessary for integrating top-down cue information with bottom-up sensory information. Conversely, systems involved in memory recall, semantic and self-referential processing are more strongly connected in people with top-down threat bias.

Revisiting sex differences in the acquisition and extinction of threat conditioning in humans

Findings pertaining to sex differences in the acquisition and extinction of threat conditioning, a paradigm widely used to study emotional homeostasis, remain inconsistent, particularly in humans. This inconsistency is likely due to multiple factors, one of which is sample size. Here, we pooled functional magnetic resonance imaging (fMRI) and skin conductance response (SCR) data from multiple studies in healthy humans to examine sex differences during threat conditioning, extinction learning, and extinction memory recall. We observed increased functional activation in males, relative to females, in multiple parietal and frontal (medial and lateral) cortical regions during acquisition of threat conditioning and extinction learning. Females mainly exhibited higher amygdala activation during extinction memory recall to the extinguished conditioned stimulus and also while responding to the unconditioned stimulus (presentation of the shock) during threat conditioning. Whole-brain functional connectivity analyses revealed that females showed increased connectivity across multiple networks including visual, ventral attention, and somatomotor networks during late extinction learning. At the psychophysiological level, a sex difference was only observed during shock delivery, with males exhibiting higher unconditioned responses relative to females. Our findings point to minimal to no sex differences in the expression of conditioned responses during acquisition and extinction of such responses. Functional MRI findings, however, show some distinct functional activations and connectivities between the sexes. These data suggest that males and females might use different neural mechanisms, mainly related to cognitive processing, to achieve comparable levels of acquired conditioned responses to threating cues.

Temporally and anatomically specific contributions of the human amygdala to threat and safety learning

Neural plasticity in subareas of the rodent amygdala is widely known to be essential for Pavlovian threat conditioning and safety learning. However, less consistent results have been observed in human neuroimaging studies. Here, we identify and test three important factors that may contribute to these discrepancies: the temporal profile of amygdala response in threat conditioning, the anatomical specificity of amygdala responses during threat conditioning and safety learning, and insufficient power to identify these responses. We combined data across multiple studies using a well-validated human threat conditioning paradigm to examine amygdala involvement during threat conditioning and safety learning. In 601 humans, we show that two amygdala subregions tracked the conditioned stimulus with aversive shock during early conditioning while only one demonstrated delayed responding to a stimulus not paired with shock. Our findings identify cross-species similarities in temporal- and anatomical-specific amygdala contributions to threat and safety learning, affirm human amygdala involvement in associative learning and highlight important factors for future associative learning research in humans.

My Healthy Brain: a multimodal lifestyle program to promote brain health

BACKGROUND

Promoting brain health depends on sustaining healthy behaviors across the lifespan. Yet, public adoption of lifestyle behaviors and knowledge of cognitive decline (CD) prevention remains poor. Our multidisciplinary team developed My Healthy Brain (MHB) to promote a healthy lifestyle (e.g. diet, exercise, alcohol, sleep) and build cognitive reserve (e.g. memory compensatory strategies). Our objective was to demonstrate early proof-of-concept for MHB by exploring the feasibility, acceptability, and improvement in primary lifestyle outcomes as well as secondary outcomes of self-determination and subjective wellbeing.

MATERIALS AND METHODS

Older adults with subjective (self-report only) or objective (confirmed by cognitive testing) CD, referred by neurologists to modify lifestyle risk factors (e.g. sedentary), participated in a non-randomized open pilot of MHB (N = 24). Participants completed the 8-week MHB group (90 min each) and pre-post outcome measures.

RESULTS

MHB met all a-priori set benchmarks, including good feasibility of recruitment (71% of patients screened) and enrollment (75% completed baseline), and good acceptability of treatment (75% completed 6 of 8 sessions and post-testing). Program satisfaction was excellent (100% of participants) and no adverse events were reported. We also observed improvements in primary lifestyle outcomes as well as secondary outcomes of self-determination and subjective well-being.

DISCUSSION

While MHB demonstrated preliminary feasibility and the potential to modify lifestyle risk factors for CD, the program can be improved. Future work will explore the integration of mindfulness skills with behavioral principles to bolster multidomain lifestyle change, and the live video delivery format to bypass barriers to participation.

Mindfulness and Attention Deficit Hyperactivity Disorder: A Neuropsychological Perspective

ABSTRACT

Understanding the underlying mechanisms of mindfulness has been a hot topic in recent years, not only in clinical fields but also in neuroscience. Most neuroimaging findings demonstrate that critical brain regions involved in mindfulness are responsible for cognitive functions and mental states. However, the brain is a complex system operating via multiple circuits and networks, rather than isolated brain regions solely responsible for specific functions. Mindfulness-based treatments for attention deficit hyperactivity disorder (ADHD) have emerged as promising adjunctive or alternative intervention approaches. We focus on four key brain circuits associated with mindfulness practices and effects on symptoms of ADHD and its cognitive dysfunction, including executive attention circuit, sustained attention circuit, impulsivity circuit, and hyperactivity circuit. We also expand our discussion to identify three key brain networks associated with mindfulness practices, including central executive network, default mode network, and salience network. We conclude by suggesting that more research efforts need to be devoted into identifying putative neuropsychological mechanisms of mindfulness on how it alleviates ADHD symptoms.

Mindfulness and Behavior Change

Initiating and maintaining behavior change is key to the prevention and treatment of most preventable chronic medical and psychiatric illnesses. The cultivation of mindfulness, involving acceptance and nonjudgment of present-moment experience, often results in transformative health behavior change. Neural systems involved in motivation and learning have an important role to play. A theoretical model of mindfulness that integrates these mechanisms with the cognitive, emotional, and self-related processes commonly described, while applying an integrated model to health behavior change, is needed. This integrative review (1) defines mindfulness and describes the mindfulness-based intervention movement, (2) synthesizes the neuroscience of mindfulness and integrates motivation and learning mechanisms within a mindful self-regulation model for understanding the complex effects of mindfulness on behavior change, and (3) synthesizes current clinical research evaluating the effects of mindfulness-based interventions targeting health behaviors relevant to psychiatric care. The review provides insight into the limitations of current research and proposes potential mechanisms to be tested in future research and targeted in clinical practice to enhance the impact of mindfulness on behavior change.

Mindfulness Training Improves Cognition and Strengthens Intrinsic Connectivity Between the Hippocampus and Posteromedial Cortex in Healthy Older Adults

Maintaining optimal cognitive functioning throughout the lifespan is a public health priority. Evaluation of cognitive outcomes following interventions to promote and preserve brain structure and function in older adults, and associated neural mechanisms, are therefore of critical importance. In this randomized controlled trial, we examined the behavioral and neural outcomes following mindfulness training (n = 72), compared to a cognitive fitness program (n = 74) in healthy, cognitively normal, older adults (65-80 years old). To assess cognitive functioning, we used the Preclinical Alzheimer Cognitive Composite (PACC), which combines measures of episodic memory, executive function, and global cognition. We hypothesized that mindfulness training would enhance cognition, increase intrinsic functional connectivity measured with magnetic resonance imaging (MRI) between the hippocampus and posteromedial cortex, as well as promote increased gray matter volume within those regions. Following the 8-week intervention, the mindfulness training group showed improved performance on the PACC, while the control group did not. Furthermore, following mindfulness training, greater improvement on the PACC was associated with a larger increase in intrinsic connectivity within the default mode network, particularly between the right hippocampus and posteromedial cortex and between the left hippocampus and lateral parietal cortex. The cognitive fitness training group did not show such effects. These findings demonstrate that mindfulness training improves cognitive performance in cognitively intact older individuals and strengthens connectivity within the default mode network, which is particularly vulnerable to aging affects. Clinical Trial Registration: [https://clinicaltrials.gov/ct2/show/NCT02628548], identifier [NCT02628548].

Punishment on Pause: Preliminary Evidence That Mindfulness Training Modifies Neural Responses in a Reactive Aggression Task

Reactive aggression, a hostile retaliatory response to perceived threat, has been attributed to failures in emotion regulation. Interventions for reactive aggression have largely focused on cognitive control training, which target top-down emotion regulation mechanisms to inhibit aggressive impulses. Recent theory suggests that mindfulness training (MT) improves emotion regulation via both top-down and bottom-up neural mechanisms and has thus been proposed as an alternative treatment for aggression. Using this framework, the current pilot study examined how MT impacts functional brain physiology in the regulation of reactive aggression. Participants were randomly assigned to 2 weeks of MT (n = 11) or structurally equivalent active coping training (CT) that emphasizes cognitive control (n = 12). Following training, participants underwent functional magnetic resonance imaging (fMRI) during a retaliatory aggression task, a 16-trial game in which participants could respond to provocation by choosing whether or not to retaliate in the next round. Training groups did not differ in levels of aggression displayed. However, participants assigned to MT exhibited enhanced ventromedial prefrontal cortex (vmPFC) recruitment during punishment events (i.e., the aversive consequence of losing) relative to those receiving active CT. Conversely, the active coping group demonstrated greater dorsomedial prefrontal cortex (dmPFC) activation when deciding how much to retaliate, in line with a bolstered top-down behavior monitoring function. The findings suggest that mindfulness and cognitive control training may regulate aggression via different neural circuits and at different temporal stages of the provocation-aggression cycle. Trial Registration: identification no. NCT03485807.

Mindfulness practice for protecting mental health during the COVID-19 pandemic

Emerging evidence shows that the coronavirus disease 2019 (COVID-19) pandemic is negatively affecting mental health around the globe. Interventions to alleviate the psychological impact of the pandemic are urgently needed. Whether mindfulness practice may protect against the harmful emotional effects of a pandemic crisis remains hitherto unknown. We investigated the influence of mindfulness training on mental health during the COVID-19 outbreak in China. We hypothesized that mindfulness practitioners might manifest less pandemic-related distress, depression, anxiety, and stress than non-practitioners and that more frequent practice would be associated with an improvement in mental health during the pandemic. Therefore, we assessed pandemic-related distress and symptoms of depression, anxiety, and stress, as well as the frequency of meditation practice at the peak of new infections (Feb 4-5; N = 673) and three weeks later (Feb 29-30; N = 521) in mindfulness practitioners via online questionnaires. Self-reported symptoms were also collected from non-practitioners at peak time only (N = 1550). We found lower scores of pandemic-related distress in mindfulness practitioners compared to non-practitioners. In general, older participants showed fewer symptoms of depression and anxiety. In younger practitioners, pandemic-related distress decreased from peak to follow-up. Importantly, increased mindfulness training during the preceding two weeks was associated with lower scores of depression and anxiety at both assessments. Likewise, practice frequency predicted individual improvement in scores of depression, anxiety, and stress at follow-up. Our results indicate that mindfulness meditation might be a viable low-cost intervention to mitigate the psychological impact of the COVID-19 crisis and future pandemics.

Motivation and reward mechanisms in health behavior change processes

With increasing prevalence of lifestyle-related chronic diseases worldwide, understanding health behavior change and the development of successful interventions to support lifestyle modification is gaining increasing interest among politicians, scientists, therapists and patients alike. A number of health behavior change theories have been developed aiming at explaining health behavior change and understanding the domains that make change more likely. Until now, only few studies have taken into account automatic, implicit or non-cognitive aspects of behavior, including emotion and positive affect. Recent progress in the neuroscience of motivation and reward systems can provide further insights into the relevance of such domains. In this integrative review, we present a description of the possible motivation and reward systems (approach/wanting = pleasure; aversion/avoiding = relief; assertion/non-wanting = quiescence) involved in behavior change. Therefore, based on established theories encompassing both initiation and maintenance of behavior change, we create a flexible seven-stage behavior change process with three engagement phases (non-engagement, motivational engagement, executive engagement) and relate the motivation and reward systems to each of these stages. We propose that either appetitive (preferably) or aversive motivational salience is activated during motivational engagement, that learning leads to continued behavior and that assertive salience prevails when the new behavior has become habitual. We discuss under which circumstances these mechanisms and reward-motivation pathways are likely to occur and address potential shortcomings of our proposed theoretical framework. We highlight implications for future interventions aiming at lifestyle modification.

Hippocampal circuits underlie improvements in self-reported anxiety following mindfulness training

INTRODUCTION

Mindfulness meditation has successfully been applied to cultivate skills in self-regulation of emotion, as it employs the unbiased present moment awareness of experience. This heightened attention to and awareness of sensory experience has been postulated to create an optimal therapeutic exposure condition and thereby improve extinction learning. We recently demonstrated increased connectivity in hippocampal circuits during the contextual retrieval of extinction memory following mindfulness training.

METHODS

Here, we examine the role of structural changes in hippocampal subfields following mindfulness training in a randomized controlled longitudinal study using a two-day fear-conditioning and extinction protocol.

RESULTS

We demonstrate an association between mindfulness training-related increases in subiculum and decreased hippocampal connectivity to lateral occipital regions during contextual retrieval of extinguished fear. Further, we demonstrate an association between decreased connectivity and decreases in self-reported anxiety following mindfulness training.

CONCLUSIONS

The results highlight the role of the subiculum in gating interactions with contextual stimuli during memory retrieval and, also, the mechanisms through which mindfulness training may foster resilience.

A Computational Theory of Mindfulness Based Cognitive Therapy from the "Bayesian Brain" Perspective

Mindfulness Based Cognitive Therapy (MBCT) was developed to combine methods from cognitive behavioral therapy and meditative techniques, with the specific goal of preventing relapse in recurrent depression. While supported by empirical evidence from multiple clinical trials, the cognitive mechanisms behind the effectiveness of MBCT are not well understood in computational (information processing) or biological terms. This article introduces a testable theory about the computational mechanisms behind MBCT that is grounded in "Bayesian brain" concepts of perception from cognitive neuroscience, such as predictive coding. These concepts regard the brain as embodying a model of its environment (including the external world and the body) which predicts future sensory inputs and is updated by prediction errors, depending on how precise these error signals are. This article offers a concrete proposal how core concepts of MBCT-(i) the being mode (accepting whatever sensations arise, without judging or changing them), (ii) decentering (experiencing thoughts and percepts simply as events in the mind that arise and pass), and (iii) cognitive reactivity (changes in mood reactivate negative beliefs)-could be understood in terms of perceptual and metacognitive processes that draw on specific computational mechanisms of the "Bayesian brain." Importantly, the proposed theory can be tested experimentally, using a combination of behavioral paradigms, computational modelling, and neuroimaging. The novel theoretical perspective on MBCT described in this paper may offer opportunities for finessing the conceptual and practical aspects of MBCT.

The effects of aversive-to-appetitive counterconditioning on implicit and explicit fear memory

Counterconditioning (CC) is a form of retroactive interference that inhibits expression of learned behavior. But similar to extinction, CC can be a fairly weak and impermanent form of interference, and the original behavior is prone to relapse. Research on CC is limited, especially in humans, but prior studies suggest it is more effective than extinction at modifying some behaviors (e.g., preference or valence ratings) than others (e.g., physiological arousal). Here, we used a within-subjects design to compare the effects of aversive-to-appetitive CC versus standard extinction on two separate tests of long-term memory in human adults: implicit physiological arousal and explicit episodic memory. Participants underwent Pavlovian fear conditioning to two semantic categories (animals, tools) paired with an electric shock. Conditioned stimuli (i.e., category exemplars) from one category were then extinguished, while stimuli from the other category were paired with a positive outcome. Participants returned 24-h later for a test of skin conductance responses (SCR) to the conditioned exemplars, as well as a surprise recognition memory test for stimuli encoded the previous day. Results showed reduced SCRs at a test for unique stimuli from a category that had undergone CC, relative to stimuli from a category that had undergone standard extinction. Additionally, participants selectively remembered more stimuli encoded during CC than extinction. These results provide new evidence that aversive-to-appetitive CC, as compared to extinction, strengthens memory for items directly associated with a positive outcome, which may provide stronger retrieval competition against a fear memory at test to help diminish fear relapse.

Breath-focused mindfulness alters early and late components during emotion regulation

Breath-focused mindfulness (BFM), which induces changes in brain structure and function, is applied in the clinical treatment of mental disorders as a method to regulate one's emotions. However, whether BFM works through a top-down emotional regulation strategy to alter brain dynamics and its relationship with individual differences in trait mindfulness are unclear. Event-related potentials (ERPs) of 20 healthy BFM-naïve undergraduates were recorded when they conducted BFM/viewing tasks while viewing affective pictures. Participants completed the Attentional Control Scale (ACS) and the Mindful Attention Awareness Scale (MAAS). The results indicated that under the viewing condition, positive and negative pictures elicited greater P1, N2, and late positive potential (LPP) amplitudes than did neutral pictures. However, BFM attenuated P1, N2, and LPP amplitudes for positive and negative pictures but not for neutral pictures. P1 amplitudes for emotional minus neutral pictures correlated with individual differences in focus attention measured by the ACS, while N2 amplitudes for emotional minus neutral pictures correlated with individual differences in trait mindfulness measured by the MAAS. These observations suggest that, consistent with the dual-process model, BFM is an effective emotion regulation strategy and might activate the dorsal top-down prefrontal system to alter early and late neural dynamics of affective processing.