Neuro-imaging of mindfulness meditations: implications for clinical practice

A systematic review and activation likelihood estimation meta-analysis of fMRI studies on arousing or wake-promoting effects in Buddhist meditation

Conventional Buddhist texts illustrate meditation as a condition of relaxed alertness that must fend against extreme hypoarousal (sleep, drowsiness) and extreme hyperarousal (restlessness). Theoretical, neurophysiological, and neuroimaging investigations of meditation have highlighted the relaxing effects and hypoarousing without emphasizing the alertness-promoting effects. Here we performed a systematic review supported by an activation-likelihood estimate (ALE) meta-analysis in an effort to counterbalance the surfeit of scholarship emphasizing the hypoarousing and relaxing effects of different forms of Buddhist meditation. Specifically, the current systematic review-cum-meta-analytical review seeks to highlight more support for meditation's wake-promoting effects by drawing from neuroimaging research during wakefulness and meditation. In this systematic review and meta-analysis of 22 fMRI studies, we aim to highlight support for Buddhist meditation's wake-promoting or arousing effects by identifying brain regions associated with alertness during meditation. The most significant peaks were localized medial frontal gyrus (MFG) and precuneus. We failed to determine areas ostensibly common to alertness-related meditation such as the medial prefrontal cortex (mPFC), superior parietal lobule, basal ganglia, thalamus, most likely due to the relatively fewer fMRI investigations that used wakefulness-promoting meditation techniques. Also, we argue that forthcoming research on meditation, related to alertness or wakefulness, continues to adopt a multi-modal method to investigate the correlation between actual behaviors and neural networks connected to Buddhist meditation. Moreover, we recommend the implementation of fMRI paradigms on Buddhist meditation with clinically diagnosed participants to complement recent trends in psychotherapy such as mindfulness-based cognitive therapy (MBCT).

Respiratory therapy for the treatment of anxiety: Meta-analytic review and regression

OBJECTIVE

Respiratory abnormalities are a hallmark of anxiety symptomatology and may serve as clinically useful modifiers for alleviating anxiety symptoms. However, gold-standard anxiety treatments (e.g., cognitive-behavioral interventions) often do not directly address respiratory components despite their theoretical utility and clinical accessibility. This review examined the clinical effectiveness of respiratory interventions, interventions that directly target respiration abnormalities and processes, in treating trait anxiety symptoms.

METHODS

The final analysis included 40 randomized controlled trials including at least one measure of trait anxiety, a respiratory-focused intervention group, and a non-respiratory control-group (active or inactive treatment). Overall effects of respiratory focused interventions were examined, as well as the effect of hypothesized moderators.

RESULTS

Respiratory component interventions yielded significantly greater improvements (moderate to large effect) in anxiety symptoms than controls, with the stronger effects observed in comparison to inactive, rather than active, control conditions. Significant heterogeneity in findings suggests that variability in intervention design, population, and control comparison may obfuscate interpretation of findings.

CONCLUSIONS

Evidence supports the clinical utility of respiratory interventions as either an independent anxiety treatment, or as an adjunct to other interventions. Clinical and research implications of findings along with recommendations for ongoing investigations in this domain are discussed.

Mindfulness-based stress reduction training modulates striatal and cerebellar connectivity

Mindfulness is a meditation practice frequently associated with changes in subjective evaluation of cognitive and sensorial experience, as well as with modifications of brain activity and morphometry. Aside from the anatomical localization of functional changes induced by mindfulness practice, little is known about changes in functional and effective functional magnetic resonance imaging (fMRI) connectivity. Here we performed a connectivity fMRI analysis in a group of healthy individuals participating in an 8-week mindfulness-based stress reduction (MBSR) training program. Data from both a "mind-wandering" and a "meditation" state were acquired before and after the MBSR course. Results highlighted decreased local connectivity after training in the right anterior putamen and insula during spontaneous mind-wandering and the right cerebellum during the meditative state. A further effective connectivity analysis revealed (a) decreased modulation by the anterior cingulate cortex over the anterior portion of the putamen, and (b) a change in left and right posterior putamen excitatory input and inhibitory output with the cerebellum, respectively. Results suggest a rearrangement of dorsal striatum functional and effective connectivity in response to mindfulness practice, with changes in cortico-subcortical-cerebellar modulatory dynamics. Findings might be relevant for the understanding of widely documented mindfulness behavioral effects, especially those related to pain perception.

From the neurobiological basis of comorbid alcohol dependence and depression to psychological treatment strategies: study protocol of a randomized controlled trial

BACKGROUND

Alcohol use disorder and depression occur commonly in the community. Even though this high-prevalence comorbidity is associated with poorer posttreatment outcomes and greater utilization of costly treatment services, existing treatment trials often exclude patients with comorbid depressive and alcohol use disorders. Past research suggests that symptoms such as craving and anhedonia might be associated with alterations within the reward circuit, while emotion regulation deficits are related to disruptions within the default mode network. The aim of this clinical neuroimaging study is to transfer previous research about the reward circuit and default mode network underlying alcohol use disorder and depression to achieve a better understanding of neural signatures characterizing their comorbidity. In addition, the neurobiological results will be used to test whether two psychotherapeutic intervention programs, mindfulness-based training and behavioral activation training, are able to positively influence the identified pathomechanisms.

METHODS

By means of functional magnetic resonance imaging (fMRI), 60 comorbid alcohol dependent and depressed patients are compared to 30 patients with depression only, 30 patients with alcohol use disorder only and 30 healthy control participants. Comorbid patients are randomized to either receive a behavioral activation or mindfulness based training and asked to participate in a second fMRI session and 3 month follow-up assessment. Thereby, we plan to explore whether these brief group psychotherapeutic intervention programs are able to positively influence the identified neurobiological pathomechanisms. The primary outcomes are reward and default mode network activity and connectivity evoked by paradigms measuring different facets of reward and emotion processing. Secondary outcome measures include craving and depression scores, as well as relapse rates. Predictors include participants' characteristics, personality traits and indicators of mental health.

DISCUSSION

The objective of the project is to identify common and/or distinct neural signatures underlying the comorbidity of alcohol dependence and depression. If the neurobiological understanding of alcohol addiction and depression is improved, this could potentially serve as a key predictor of treatment response to specific types of behavioral or mindfulness therapies hypothesized to alter reward and resting state systems.

TRIAL REGISTRATION

German Clinical Trial Register DRKS00010249 . The trial was registered January 23th 2017.

Healthy Learning Mind - a school-based mindfulness and relaxation program: a study protocol for a cluster randomized controlled trial

BACKGROUND

Mindfulness has shown positive effects on mental health, mental capacity and well-being among adult population. Among children and adolescents, previous research on the effectiveness of mindfulness interventions on health and well-being has shown promising results, but studies with methodologically sound designs have been called for. Few intervention studies in this population have compared the effectiveness of mindfulness programs to alternative intervention programs with adequate sample sizes.

METHODS/DESIGN

Our primary aim is to explore the effectiveness of a school-based mindfulness intervention program compared to a standard relaxation program among a non-clinical children and adolescent sample, and a non-treatment control group in school context. In this study, we systematically examine the effects of mindfulness intervention on mental well-being (primary outcomes being resilience; existence/absence of depressive symptoms; experienced psychological strengths and difficulties), cognitive functions, psychophysiological responses, academic achievements, and motivational determinants of practicing mindfulness. The design is a cluster randomized controlled trial with three arms (mindfulness intervention group, active control group, non-treatment group) and the sample includes 59 Finnish schools and approx. 3 000 students aged 12-15 years. Intervention consists of nine mindfulness based lessons, 45 mins per week, for 9 weeks, the dose being identical in active control group receiving standard relaxation program called Relax. The programs are delivered by 14 educated facilitators. Students, their teachers and parents will fill-in the research questionnaires before and after the intervention, and they will all be followed up 6 months after baseline. Additionally, students will be followed 12 months after baseline. For longer follow-up, consent to linking the data to the main health registers has been asked from students and their parents.

DISCUSSION

The present study examines systematically the effectiveness of a school-based mindfulness program compared to a standard relaxation program, and a non-treatment control group. A strength of the current study lies in its methodologically rigorous, randomized controlled study design, which allows novel evidence on the effectiveness of mindfulness over and above a standard relaxation program.

TRIAL REGISTRATION

ISRCTN18642659 . Retrospectively registered 13 October 2015.

Mechanistic Pathways of Mindfulness Meditation in Combat Veterans With Posttraumatic Stress Disorder

OBJECTIVE

This study's objective was to evaluate the effect of two common components of meditation (mindfulness and slow breathing) on potential mechanistic pathways.

METHODS

A total of 102 combat veterans with posttraumatic stress disorder (PTSD) were randomized to (a) the body scan mindfulness meditation (MM), (b) slow breathing (SB) with a biofeedback device, (c) mindful awareness of the breath with an intention to slow the breath (MM+SB), or (d) sitting quietly (SQ). Participants had 6 weekly one-on-one sessions with 20 minutes of daily home practice. The mechanistic pathways and measures were as follows: (a) autonomic nervous system (hyperarousal symptoms, heart rate [HR], and heart rate variability [HRV]); (b) frontal cortex activity (attentional network task [ANT] conflict effect and event-related negativity and intrusive thoughts); and (c) hypothalamic-pituitary-adrenal axis (awakening cortisol). PTSD measures were also evaluated.

RESULTS

Meditation participants had significant but modest within-group improvement in PTSD and related symptoms, although there were no effects between groups. Perceived impression of PTSD symptom improvement was greater in the meditation arms compared with controls. Resting respiration decreased in the meditation arms compared with SQ. For the mechanistic pathways, (a) subjective hyperarousal symptoms improved within-group (but not between groups) for MM, MM+SB, and SQ, while HR and HRV did not; (b) intrusive thoughts decreased in MM compared with MM+SB and SB, while the ANT measures did not change; and (c) MM had lower awakening cortisol within-group (but not between groups).

CONCLUSION

Treatment effects were mostly specific to self-report rather than physiological measures. Continued research is needed to further evaluate mindfulness meditation's mechanism in people with PTSD.

Increases in the right dorsolateral prefrontal cortex and decreases the rostral prefrontal cortex activation after-8 weeks of focused attention based mindfulness meditation

Mindfulness meditation is a form of attention control training. The training exercises the ability to repeatedly focus attention. We addressed the activation changes related to an 8-weeks mindfulness-oriented focused attention meditation training on an initially naïve subject cohort. Before and after training participants underwent an fMRI experiment, thus, although not strictly a cross over design, they served as their internal own control. During fMRI they exercised focused attention on breathing and body scan as compared to resting. We found increased and decreased activation in different parts of the prefrontal cortex (PFC) by comparing pre- vs. post-mindfulness training (MT) during breathing and body scan meditation exercises that were compared against their own resting state. In the post-MT (vs. pre-MT) meditation increased activation in the right dorsolateral PFC and in the left caudate/anterior insula and decreased activation in the rostral PFC and right parietal area 3b. Thus a brief mindfulness training caused increased activation in areas involved in sustaining and monitoring the focus of attention (dorsolateral PFC), consistent with the aim of mindfulness that is exercising focused attention mechanisms, and in the left caudate/anterior insula involved in attention and corporeal awareness and decreased activation in areas part of the "default mode" network and is involved in mentalizing (rostral PFC), consistent with the ability trained by mindfulness of reducing spontaneous mind wandering.

What are neuroimaging meta-analytic procedures?

Activation likelihood estimation (ALE) meta-analyses allow investigators to integrate the results of multiple neuroimaging studies, potentially yielding novel results that may not have been evident in the individual studies. Here, we provide a brief, introductory description of ALE methods for readers without extensive expertise in neuroimaging.

Mindfulness and emotion regulation--an fMRI study

Mindfulness--an attentive non-judgmental focus on present experiences--is increasingly incorporated in psychotherapeutic treatments as a skill fostering emotion regulation. Neurobiological mechanisms of actively induced emotion regulation are associated with prefrontally mediated down-regulation of, for instance, the amygdala. We were interested in neurobiological correlates of a short mindfulness instruction during emotional arousal. Using functional magnetic resonance imaging, we investigated effects of a short mindfulness intervention during the cued expectation and perception of negative and potentially negative pictures (50% probability) in 24 healthy individuals compared to 22 controls. The mindfulness intervention was associated with increased activations in prefrontal regions during the expectation of negative and potentially negative pictures compared to controls. During the perception of negative stimuli, reduced activation was identified in regions involved in emotion processing (amygdala, parahippocampal gyrus). Prefrontal and right insular activations when expecting negative pictures correlated negatively with trait mindfulness, suggesting that more mindful individuals required less regulatory resources to attenuate emotional arousal. Our findings suggest emotion regulatory effects of a short mindfulness intervention on a neurobiological level.

Mechanism of integrative body-mind training

Integrative Body-Mind Training (IBMT) originates from ancient Eastern tradition. The method stresses no effort to control thoughts, but instead a state of restful alertness that allows a high degree of awareness of the body, breathing, and external instructions. A series of studies indicates that IBMT improves attention and self-regulation through interaction between the central (brain) and the autonomic (body) nervous systems. The present review mainly summarizes the recent results of IBMT studies and proposes how it changes the state of brain and body to lead to positive outcomes. Future directions in this field are also discussed.

Self-referential thinking, suicide, and function of the cortical midline structures and striatum in mood disorders: possible implications for treatment studies of mindfulness-based interventions for bipolar depression

Bipolar depression is often refractory to treatment and is frequently associated with anxiety symptoms and elevated suicide risk. There is a great need for adjunctive psychotherapeutic interventions. Treatments with effectiveness for depressive and anxiety symptoms as well as suicide-related thoughts and behaviors would be particularly beneficial. Mindfulness-based interventions hold promise, and studies of these approaches for bipolar disorder are warranted. The aim of this paper is to provide a conceptual background for such studies by reviewing key findings from diverse lines of investigation. Results of that review indicate that cortical midline structures (CMS) appear to link abnormal self-referential thinking to emotional dysregulation in mood disorders. Furthermore, CMS and striatal dysfunction may play a role in the neuropathology underlying suicide-related thoughts and behaviors. Thus, combining studies of mindfulness interventions targeting abnormal self-referential thinking with functional imaging of CMS and striatal function may help delineate the neurobiological mechanisms of action of these treatments.

Improving psychotherapy research: The example of mindfulness based interventions

The increasing number and sophistication of available psychotherapies suggests that a critical appraisal of the methodological issues of psychotherapy studies is highly needed. Several key questions regarding the efficacy of a given intervention, the understanding of whether positive effects observed following the delivery of a psychotherapeutic intervention are specifically attributable to the intervention itself or to other "non specific" factors, such as benefit expectations, therapist attention and support, and the possibility of improving psychotherapy research need an answer. This, in turn, could provide clinicians with more rigorous information about psychotherapy outcomes and could properly address several shortcomings that are frequently observed in current psychotherapy studies. Accordingly, in this editorial I will highlight some of the most important critical issues that a well designed psychotherapy study should take into account, including the need for appropriate control groups, appropriate randomization and blinding procedures, and the importance of performing appropriately powered studies that include a sufficiently long follow-up period. Finally, I will build on my expertise in the field of mindfulness based interventions, in particular mindfulness based stress reduction and mindfulness based cognitive therapy, to show how such issues have been and can be successfully implemented in the design of future psychotherapy studies.