Background

The role of hippocampus in context-dependent recall of extinction is well recognized. However, little is known about how intervention-induced changes in hippocampal networks relate to improvements in extinction learning. In this study, we hypothesized that mindfulness training creates an optimal exposure condition by heightening attention and awareness of present moment sensory experience, leading to enhanced extinction learning, improved emotion regulation, and reduced anxiety symptoms.

Methods

We tested this hypothesis in a randomized controlled longitudinal study design using a 2-day fear conditioning and extinction protocol. The mindfulness training group included 42 participants (28 female) and the control group included 25 participants (15 female).

Results

We show that mindfulness training is associated with differential engagement of the right supramarginal gyrus as well as hippocampal-cortical reorganization. We also report enhanced hippocampal connectivity to primary sensory cortex during retrieval of extinguished stimuli following mindfulness training.

Conclusion

These findings suggest hippocampal dependent changes in contextual retrieval as one plausible neural mechanism through which mindfulness-based interventions enhance fear extinction and foster stress resilience.

Objective: We investigated common and dissociable neural and psychological correlates of two widely used meditation-based stress reduction programs.

Methods: Participants were randomized to the Relaxation Response (RR; n = 18; 56% female) or the Mindfulness-Based Stress Reduction (MBSR; n = 16; 56% female) programs. Both programs use a “bodyscan” meditation; however, the RR program explicitly emphasizes physical relaxation during this practice, whereas the MBSR program emphasizes mindful awareness with no explicit relaxation instructions. After the programs, neural activity during the respective meditation was investigated using functional magnetic resonance imaging.

Results: Both programs were associated with reduced stress (for RR, from 14.1 ± 6.6 to 11.3 ± 5.5 [Cohen's d = 0.50; for MBSR, from 17.7 ± 5.7 to 11.9 ± 5.0 [Cohen's d = 1.02]). Conjunction analyses revealed functional coupling between ventromedial prefrontal regions and supplementary motor areas (p < .001). The disjunction analysis indicated that the RR bodyscan was associated with stronger functional connectivity of the right inferior frontal gyrus—an important hub of intentional inhibition and control—with supplementary motor areas (p < .001, family-wise error [FWE] rate corrected). The MBSR program was uniquely associated with improvements in self-compassion and rumination, and the within-group analysis of MBSR bodyscan revealed significant functional connectivity of the right anterior insula—an important hub of sensory awareness and salience—with pregenual anterior cingulate during bodyscan meditation compared with rest (p = .03, FWE corrected).

Conclusions: The bodyscan exercises in each program were associated with both overlapping and differential functional coupling patterns, which were consistent with each program's theoretical foundation. These results may have implications for the differential effects of these programs for the treatment of diverse conditions.

In response to our article, Davidson and Dahl offer commentary and advice regarding additional topics crucial to a comprehensive prescriptive agenda for future research on mindfulness and meditation. Their commentary raises further challenges and provides an important complement to our article. More consideration of these issues is especially welcome because limited space precluded us from addressing all relevant topics. While we agree with many of Davidson and Dahl’s suggestions, the present reply (a) highlights reasons why the concerns we expressed are still especially germane to mindfulness and meditation research (even though those concerns may not be entirely unique) and (b) gives more context to other issues posed by them. We discuss special characteristics of individuals who participate in mindfulness and meditation research and focus on the vulnerability of this field inherent in its relative youthfulness compared to other more mature scientific disciplines. Moreover, our reply highlights the serious consequences of adverse experiences suffered by a significant subset of individuals during mindfulness and other contemplative practices. We also scrutinize common contemporary applications of mindfulness and meditation to illness, and some caveats are introduced regarding mobile technologies for guidance of contemplative practices. 

An impaired ability to suppress currently irrelevant mental-sets is a key cognitive deficit in depression. Mindfulness-based cognitive therapy (MBCT) was specifically designed to help depressed individuals avoid getting caught in such irrelevant mental-sets. In the current study, a group assigned to MBCT plus treatment-as-usual (n = 22) exhibited significantly lower depression scores and greater improvements in irrelevant mental-set suppression compared to a wait-list plus treatment-as-usual (n = 18) group. Improvements in mental-set-suppression were associated with improvements in depression scores. Results provide the first evidence that MBCT can improve suppression of irrelevant mental-sets and that such improvements are associated with depressive alleviation.

OBJECTIVE: 

Chronic pain is a disabling illness, often comorbid with depression. We performed a randomized controlled pilot study on mindfulness-based cognitive therapy (MBCT) targeting depression in a chronic pain population.

METHOD: 

Participants with chronic pain lasting ≥ 3 months; DSM-IV major depressive disorder (MDD), dysthymic disorder, or depressive disorder not otherwise specified; and a 16-item Quick Inventory of Depressive Symptomatology-Clinician Rated (QIDS-C₁₆) score ≥ 6 were randomly assigned to MBCT (n = 26) or waitlist (n = 14). We adapted the original MBCT intervention for depression relapse prevention by modifying the psychoeducation and cognitive-behavioral therapy elements to an actively depressed chronic pain population. We analyzed an intent-to-treat (ITT) and a per-protocol sample; the per-protocol sample included participants in the MBCT group who completed at least 4 of 8 sessions. Changes in scores on the QIDS-C₁₆ and 17-item Hamilton Depression Rating Sale (HDRS₁₇) were the primary outcome measures. Pain, quality of life, and anxiety were secondary outcome measures. Data collection took place between January 2012 and July 2013.

RESULTS: 

Nineteen participants (73%) completed the MBCT program. No significant adverse events were reported in either treatment group. ITT analysis (n = 40) revealed no significant differences. Repeated-measures analyses of variance for the per-protocol sample (n = 33) revealed a significant treatment × time interaction (F₁,₃₁ = 4.67, P = .039, η²p = 0.13) for QIDS-C₁₆ score, driven by a significant decrease in the MBCT group (t₁₈ = 5.15, P < .001, d = >1.6), but not in the control group (t₁₃ = 2.01, P = .066). The HDRS₁₇ scores did not differ significantly between groups. The study ended before the projected sample size was obtained, which might have prevented effect detection in some outcome measures.

CONCLUSIONS: 

MBCT shows potential as a treatment for depression in individuals with chronic pain, but larger controlled trials are needed.

TRIAL REGISTRATION: 

ClinicalTrials.gov identifier: NCT01473615​​.

An impaired ability to suppress currently irrelevant mental-sets is a key cognitive deficit in depression. Mindfulness-based cognitive therapy (MBCT) was specifically designed to help depressed individuals avoid getting caught in such irrelevant mental-sets. In the current study, a group assigned to MBCT plus treatment-as-usual (n = 22) exhibited significantly lower depression scores and greater improvements in irrelevant mental-set suppression compared to a wait-list plus treatment-as-usual (n = 18) group. Improvements in mental-set-suppression were associated with improvements in depression scores. Results provide the first evidence that MBCT can improve suppression of irrelevant mental-sets and that such improvements are associated with depressive alleviation.

Keywords

Mindfulness-based cognitive therapyDepressionMental-setCompetitor rule suppression

Body awareness has been proposed as one of the major mechanisms of mindfulness interventions, and it has been shown that chronic pain and depression are associated with decreased levels of body awareness. We investigated the effect of Mindfulness-Based Cognitive Therapy (MBCT) on body awareness in patients with chronic pain and comorbid active depression compared to treatment as usual (TAU; N=31). Body awareness was measured by a subset of the Multidimensional Assessment of Interoceptive Awareness (MAIA) scales deemed most relevant for the population. These included: Noticing, Not-Distracting, Attention Regulation, Emotional Awareness, and Self-Regulation. In addition, pain catastrophizing was measured by the Pain Catastrophizing Scale (PCS). These scales had adequate to high internal consistency in the current sample. Depression severity was measured by the Quick Inventory of Depressive Symptomatology – Clinician rated (QIDS-C16). Increases in the MBCT group were significantly greater than in the TAU group on the ‘Self-Regulation’ and ‘Not Distracting’ scales. Furthermore, the positive effect of MBCT on depression severity was mediated by ‘Not Distracting’. These findings provide preliminary evidence that a mindfulness-based intervention may increase facets of body awareness as assessed with the MAIA in a population of pain patients with depression. Furthermore, they are consistent with a long hypothesized mechanism for mindfulness and emphasize the clinical relevance of body awareness.

Mindfulness has been suggested to impact emotional learning, but research on these processes is scarce. The classical fear conditioning/extinction/extinction retention paradigm is a well-known method for assessing emotional learning. The present study tested the impact of mindfulness training on fear conditioning and extinction memory and further investigated whether changes in white matter fiber tracts might support such changes. The uncinate fasciculus (UNC) was of particular interest in the context of emotional learning. In this pilot study, 46 healthy participants were quasi-randomized to a Mindfulness-Based Stress Reduction (MBSR, N = 23) or waitlist control (N = 23) group and underwent a two-day fear conditioning, extinction learning, and extinction memory protocol before and after the course or control period. Skin conductance response (SCR) data served to measure the physiological response during conditioning and extinction memory phases. Diffusion tensor imaging (DTI) data were analyzed with probabilistic tractography and analyzed for changes of fractional anisotropy in the UNC. During conditioning, participants were able to maintain a differential response to conditioned vs. not conditioned stimuli following the MBSR course (i.e., higher sensitivity to the conditioned stimuli), while controls dropped the response. Extinction memory results were not interpretable due to baseline differences. MBSR participants showed a significant increase in fractional anisotropy in the UNC, while controls did not (group by time interaction missed significance). Pre-post changes in UNC were correlated with changes in the response to the conditioned stimuli. The findings suggest effects of mindfulness practice on the maintenance of sensitivity of emotional responses and suggest underlying neural plasticity. (ClinicalTrials.gov, Identifier NCT01320969, https://clinicaltrials.gov/ct2/show/NCT01320969).

There has been a growing interest in understanding how contemplative practices affect brain functional organization. However, most studies have restricted their exploration to predefined networks. Furthermore, scientific comparisons of different contemplative traditions are largely lacking. Here we explored differences in whole brain resting state functional connectivity between experienced yoga practitioners, experienced meditators, and matched controls. Analyses were repeated in an independent sample of experienced meditators and matched controls. Analyses utilizing Network-Based Statistics (Zalesky et al., 2010) revealed difference components for yoga practitioners > controls and meditators > controls in which the right caudate was a central node. Follow up analyses revealed that yoga practitioners and meditators had significantly greater degree centrality in the caudate than controls. This greater degree centrality was not driven by single connections but by greater connectivity between the caudate and numerous brain regions. Findings of greater caudate connectivity in meditators than in controls was replicated in an independent dataset. These findings suggest that yoga and meditation practitioners have stronger functional connectivity within basal ganglia cortico-thalamic feedback loops than non-practitioners. Although we could not provide evidence for its mechanistic role, this greater connectivity might be related to the often reported effects of meditation and yoga on behavioral flexibility, mental health, and well-being.

In light of a growing interest in contemplative practices such as meditation, the emerging field of contemplative science has been challenged to describe and objectively measure how these practices affect health and well-being. While “mindfulness” itself has been proposed as a measurable outcome of contemplative practices, this concept encompasses multiple components, some of which, as we review here, may be better characterized as equanimity. Equanimity can be defined as an even-minded mental state or dispositional tendency toward all experiences or objects, regardless of their origin or their affective valence (pleasant, unpleasant, or neutral). In this article, we propose that equanimity be used as an outcome measure in contemplative research. We first define and discuss the inter-relationship between mindfulness and equanimity from the perspectives of both classical Buddhism and modern psychology and present existing meditation techniques for cultivating equanimity. We then review psychological, physiological, and neuroimaging methods that have been used to assess equanimity either directly or indirectly. In conclusion, we propose that equanimity captures potentially the most important psychological element in the improvement of well-being, and therefore should be a focus in future research studies.