Impact of short- and long-term mindfulness meditation training on amygdala reactivity to emotional stimuli

May combine two claims.

Self-reported lifetime practice varied widely among long-term meditators, with a mean of 4,281 hours for daily practice and 4,658 hours for retreat practice.

“The long-term meditator group had considerable variability in self-reported total lifetime daily practice (mean=4,281(2,817) hours, range=954 – 13,605 hours) and in total lifetime retreat practice (mean=4,658 hours, range=258 – 29,710 hours)”

• AssumptionRests on an assumption: Participants' self-reported lifetime meditation hours are accurate measures of their actual practice.

May combine two claims.

No brain regions showed group differences in the whole-brain voxelwise analysis, whether comparing long-term meditators with meditation-naïve participants or MBSR with HEP after training while controlling for baseline.

“a whole-brain, voxelwise analysis did not reveal any regions in which there were differences between groups (neither for LTM versus MNP, nor MBSR versus HEP post-intervention controlling for baseline).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The two groups did not differ in how often they classified neutral IAPS pictures as neutral.

“There was no difference between groups in the percentage of neutral IAPS pictures categorized as neutral (t(120)=−0.45, b=−0.02, p=0.65, CI=[−0.11, 0.07], 2 LTM outliers removed).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The long-term meditators reported a mean of 9,081 lifetime meditation hours, mostly from mindfulness-based practices.

“LTM had an average of 9,081 lifetime hours of meditation practice, ranging from 1,439 to 32,612 total hours, and which primarily consisted of mindfulness-based practices (focused attention and OM; 86 % of daily practice hours), in addition to some practice with compassion/loving kindness meditations (14% of daily practice hours).”

The quote only partly states this claim.

There were no significant baseline differences between groups in psychophysiological interaction measures for negative versus neutral pictures.

“There were no significant differences in baseline PPI measures between groups in the same sample of participants for NEG > NEU (t(63)=−.53, b=−0.05, p=0.60, CI=[−0.23,0.13])”

May combine two claims.

Long-term meditators had lower amygdala activation than meditation-naïve participants specifically for positive pictures, but not for negative pictures, where the difference was only marginal.

“We tested separately by valence to decompose this effect and found that LTM had lower amygdala activation than MNP specifically to positive pictures, but not negative pictures (for which there was only a marginal difference between groups).”

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Controlling for gender did not change the group-difference result for the positive versus neutral psychophysiological interaction effect.

“Since there was a significant difference in the POS > NEU PPI effect by gender we also tested for group differences controlling for gender, and there were no changes in the result.”

May combine two claims.

The percentage of negative and positive pictures categorized as neutral by long-term meditators was not related to amygdala activation, and only a trend-level relationship appeared with amygdala-VMPFC connectivity during negative versus neutral pictures.

“However, we did not find a relationship between the percent of negative and positive pictures that LTM categorized as neutral and the amygdala activation, and there was only a trend-level relationship with amygdala-VMPFC connectivity during negative versus neutral pictures.”

May combine two claims.

Long-term meditators' total lifetime retreat practice predicted reduced amygdala activation to negative pictures, while total non-retreat practice hours were not associated with amygdala reactivity.

“Interestingly, long term meditators’ total lifetime practice while on retreat predicted reduced amygdala activation to negative pictures, while total hours of non-retreat practice (i.e. totally daily practice hours over the lifetime) was not associated with amygdala reactivity.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

No scan lost more than a quarter of its data to motion censoring, so no scans or participants were dropped for excessive motion.

“There were no scans with greater than 25% of the data censored for motion, and thus no participants or scans were excluded for excessive motion.”

May combine two claims.

The long-term meditator and meditation-naïve groups were comparable in age, gender, fMRI motion, education, and socioeconomic status.

“The LTM did not differ from the MNP in terms of age, gender, motion during the fMRI task, level of education, or socio-economic status measured with the Hollingshead index (Hollingshead, 1975), nor were there statistically significant effects of any of these demographic factors on any of the outcome variables, except in 2 cases as described in the Results section.”

• cites Hollingshead, 1975Not checked yet

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The randomization and intervention procedures followed those described by MacCoon et al. (2012).

“The intervention and randomization procedures were identical to that detailed by MacCoon et al. (2012)”

• cites MacCoon et al., 2012 sourceNot checked yet

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Mindfulness meditation training improves affective responses in non-clinical populations, including reduced emotional interference and decreased negative mood.

“Improvements in affective responses following mindfulness meditation training have also been shown in non-clinical populations, including reductions in emotional interference (Ortner et al., 2007) and decreased negative mood (Jha et al., 2010).”

• cites Ortner et al., 2007 sourceNot checked yet

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• cites Jha et al., 2010Not checked yet

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May combine two claims.

Including outliers in the models did not change the findings, with three exceptions noted in the text.

“All findings remain consistent when outliers are included in the model, except in 3 cases as noted in the text.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

VMPFC is specifically involved in updating value and automatically tracks changes in stimulus salience.

“Moreover, research in non-human primates indicates functional specificity of VMPFC for value updating (Rudebeck et al., 2013), providing evidence that VMPFC automatically processes information regarding the changing salience of stimuli.”

• cites Rudebeck et al., 2013 sourceNot checked yet

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In non-human primates, monosynaptic projections from MPFC to basolateral amygdala inhibit activity in the central nucleus of the amygdala.

“Non-human primate research reveals a specific mechanism for these effects whereby monosynaptic input to basolateral amygdala from MPFC inhibits activity from the central nucleus of the amygdala (Kim et al., 2011).”

• cites Kim et al., 2011 sourceNot checked yet

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Classified as probably not a substantial claim.

In the RCT, post-training amygdala activation was compared between MBSR and HEP while adjusting for baseline activation using ANCOVA.

“we compared post-training right amygdala activation in participants randomized to MBSR with the active control condition (HEP), while controlling for pre-treatment baseline activation (i.e. an analysis of covariance approach - ANCOVA).”

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The practice-duration results did not change when age was omitted from the models.

“All the results remained the same when age was not included as a covariate.”

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The study used a validated self-report measure (FFMQ non-reactivity subscale).

“the Five Facet Mindfulness Questionnaire (FFMQ; Baer et al., 2006), which includes a sub-scale that was used as a self-report measure of non-reactivity.”

• cites Baer et al., 2006 sourceNot checked yet

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May combine two claims.

The control intervention, HEP, was validated and designed to match MBSR on non-specific effects.

“a validated, active control condition (the health enhancement program; HEP) that was matched for intervention effects non-specific to mindfulness meditation (MacCoon et al., 2012).”

• cites MacCoon et al., 2012 sourceNot checked yet

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The study used an independent sample to define functional amygdala ROIs.

“Functional amygdala ROIs were identified from the contrast of Negative>Neutral IAPS pictures during a 4 s picture presentation period (analogous to the task used in the current study except participants did not make a button press response) and using data from an independent sample of 90 participants enrolled in a separate study (mean age(SD)=45.1(10.0) years, 52 female) (Grupe et al., 2017).”

• cites Grupe et al., 2017Not checked yet

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The amygdala plays a central role in generating and regulating emotion, while VMPFC is involved in automatic emotion regulation, potentially via functional coupling with the amygdala.

“The amygdala is central to emotion generation (Phelps and LeDoux, 2005) and regulation (Buhle et al., 2014), and VMPFC is implicated in automatic emotion regulation (Phelps et al., 2004; Urry et al., 2006), possibly through functional coupling with the amygdala (Banks et al., 2007; Lee et al., 2012).”

• cites Phelps and LeDoux, 2005 sourceNot checked yet

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• cites Buhle et al., 2014 sourceNot checked yet

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• cites Phelps et al., 2004 sourceNot checked yet

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During RCT data collection, experimenters did not know which group meditation-naïve participants had been assigned to.

“Experimenters were blind to the group assignment of meditation-naïve participants during data collection for the RCT.”

Classified as probably not a substantial claim.

The study used a-priori amygdala and VMPFC regions of interest.

“using a-priori amygdala and ventromedial prefrontal cortex (VMPFC) regions of interest (ROIs).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

A covariate indicated whether behavioral responses were collected in the scanner or later online; including it or not did not change the results.

“We included a covariate to control for whether participants’ behavioral data was collected concurrently in the scanner, or online afterward, and the results are consistent whether or not this covariate is included.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Affect labeling may recruit automatic emotion regulation and reduce amygdala reactivity.

“Affect labeling is a process which may engage automatic emotion regulation even absent an intention to volitionally regulate emotion, as affect labeling has been shown to dampen the amygdala response (Lieberman et al., 2007).”

• cites Lieberman et al., 2007 sourceNot checked yet

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May combine two claims.

More meditation-naïve participants than long-term meditators were recruited because the RCT required at least 30 meditation-naïve participants per group after randomization.

“We recruited a larger sample of MNP than LTM, due to the unique study design that incorporated an RCT for which we needed at least 30 MNP participants per group following randomization.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Age was included as a covariate in the practice-duration analyses because it was related to log-transformed total practice time.

“We controlled for age in the following analyses, as it was correlated with log total practice time (r=0.30 with daily practice, and r=0.15 with retreat practice), and 2 outliers were removed from all of the analyses with practice hours.”

May combine two claims.

Mindfulness meditation training can improve emotion regulation, reduce anxiety and depression symptoms, and increase positive mood.

“can improve emotion regulation, ameliorate symptoms underlying anxiety and depression and boost positive mood (Goyal et al., 2014; Hofmann et al., 2010; Jain et al., 2007).”

• cites Goyal et al., 2014 sourceNot checked yet

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• cites Hofmann et al., 2010 sourceNot checked yet

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• cites Jain et al., 2007 sourceNot checked yet

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The study used motion censoring for high motion time points.

“To further address motion, high motion time points with a framewise displacement larger than 0.9 mm (Siegel et al., 2014) were modeled out of the data with an individual regressor.”

• cites Siegel et al., 2014 sourceNot checked yet

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MBSR has been shown to reduce negative experience and speed recovery from negative challenges.

“MBSR has been shown to lead to reduced negative experience (Goldin and Gross, 2010; Kaviani et al., 2011) and quicker recovery from a negative challenge (Britton et al., 2012; Raes et al., 2009).”

• cites Goldin and Gross, 2010 sourceNot checked yet

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• cites Kaviani et al., 2011Not checked yet

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• cites Britton et al., 2012 sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Extinction learning is another automatic emotion regulation process that engages the amygdala and VMPFC.

“Extinction learning is another example of and automatic emotion regulation process and involves both amygdala and VMPFC (Phelps et al., 2004).”

• cites Phelps et al., 2004 sourceNot checked yet

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MBSR increased the amygdala-VMPFC psychophysiological interaction relative to HEP for both negative and positive pictures, implying a similar emotion-regulatory mechanism independent of valence.

“The fact that MBSR significantly increased the amygdala-VMPFC PPI effect relative to HEP training for both negative versus neutral pictures and positive versus neutral pictures lends further support to this explanation, and implies a similar emotion regulatory mechanism for reducing reactivity to affective stimuli independent of valence.”

May combine two claims.

All MBSR participants received the same intervention and came from the same geographic community, whereas long-term meditators varied more in practice type, duration, and location.

“All participants in the MBSR group received the same intervention and were recruited from the same geographic community (in Madison, WI), whereas the LTM had larger variation in practice type, duration and geographic location.”

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The current study lacked direct, objective measures of emotion regulation behavior.

“the current had no direct, objective measures of emotion regulation behavior.”

Probably not a substantial claim: may not pass S3 (load-bearing).

One possible mechanism for reduced emotional reactivity with mindfulness practice is increased exposure to emotions arising and passing while attending non-reactively.

“One mechanism that could lead to decreased emotional reactivity with practice in mindfulness meditation is through increased exposure to the arising and passing of emotions accompanied by this new habit of attending to the experience non-reactively.”

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Long-term meditators likely varied more in their motivations for practicing.

“The LTM likely also had greater variability in their motivations for engaging in practice.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Individual differences in why and whether participants could go on retreat may matter for their emotional reactivity.

“Additionally, individual differences in factors relating to participants’ choice and ability to go on retreat may be important to consider in relation to their emotional reactivity”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The authors have previously argued that this form of emotion regulation is ubiquitous and likely the most common form in everyday life.

“We have argued in other contexts that this form of emotion regulation is ubiquitous and is likely the most common form of emotion regulation in everyday life (Lapate et al., 2014).”

• cites Lapate et al., 2014 sourceNot checked yet

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The current study extends prior literature by showing similar effects with a stronger randomized controlled trial design combined with cross-sectional long-term meditator data.

“The results of the current study extend this literature in novel ways by demonstrating similar effects with a much stronger, RCT design combined with cross-sectional data from LTM.”

May combine two claims.

The inverse relationship between OM retreat practice and reactivity to negative IAPS, together with non-significant group differences in amygdala reactivity to negative IAPS, implies that changing negative-affect responses may require more intense practice over time, specifically OM meditation.

“The inverse relationship between OM retreat practice and reactivity to negative IAPS, combined with non-significant group differences in amygdala reactivity to negative IAPS implies that altering the response to negative affect may require more intense practice over time (specifically in OM meditation).”

May combine two claims.

The behavioral categorization pattern mirrors the fMRI findings and supports the hypothesis that long-term mindfulness training improves emotion regulation by reducing emotional reactivity.

“This pattern of behavioral results mirrors the pattern of results in the fMRI data and lends further support to the hypothesis that longterm mindfulness meditation training improves emotion regulation through a reduction in emotional reactivity.”

May combine two claims.

Because all long-term meditators had daily practice including OM meditation, engaging in this style while on retreat appears particularly beneficial.

“All the long-term meditators had a daily practice that included OM meditation, and so engaging in this style of practice while on retreat appears to be particularly beneficial.”

May combine two claims.

Because participants pressed a button to indicate IAPS valence, awareness of the affective source was explicit, making misattribution of affect to neutral faces less likely.

“Since participants in this study were instructed to make a button press to indicate the valence of the IAPS, this brought awareness to the source of affective information very explicitly. Thus, the affective experience induced from the IAPS was less likely to be misattributed to the neutral face stimuli.”

May combine two claims.

Participants with mindfulness meditation training may have engaged automatic emotion regulation more easily because of the affect labeling component, possibly leading to lower amygdala reactivity.

“Therefore, participants with mindfulness meditation training may have more easily or robustly engaged this automatic form of emotion regulation due to the affect labeling component of the task, possibly leading to lower amygdala reactivity.”

Classified as probably not a substantial claim.

Prior research has separated the neural basis of pleasure from the wanting associated with approach behavior.

“Prior research has dissociated the neural basis of pleasure from that of the “wanting” associated with approach behavior (Smith et al., 2011).”

• cites Smith et al., 2011 sourceNot checked yet

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Classified as probably not a substantial claim. May combine two claims.

Research has shown that affect labeling can act as implicit emotion regulation, dampening amygdala response and involving increased ventrolateral prefrontal activation mediated by VMPFC.

“Furthermore, research has shown that affect labeling can serve as a form of implicit emotion regulation and result in dampening of the amygdala response, which was associated with increased ventrolateral PFC activation mediated by VMPFC (Lieberman et al., 2007).”

• cites Lieberman et al., 2007 sourceNot checked yet

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The exploratory nature of the behavioral analysis and technical difficulties recording button responses limited inference and power to detect an effect.

“The exploratory nature of our behavioral analysis, and the technical difficulties with recording button responses in the scanner, greatly limited inference from these results, as well as our power to detect an effect.”

May combine two claims.

The amygdala likely marks wanting more than liking, whereas ventral pallidum circuitry is uniquely associated with liking.

“It is likely that the amygdala, a key node in the salience network, marks wanting more than liking whereas the work of Berridge and colleagues suggests that local circuitry within the ventral pallidum is uniquely associated with liking (Smith et al., 2011).”

• cites Smith et al., 2011 sourceNot checked yet

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Classified as probably not a substantial claim. May combine two claims.

Labeling experiences, including affective ones, is a component of mindfulness meditation training and has been proposed as a mechanism by which such training improves emotion regulation.

“Labeling experiences – including affective experiences – is also a component of mindfulness mediation training, and has been previously proposed as one possible mechanism by which such practices train emotion regulation (Lutz et al., 2008).”

• cites Lutz et al., 2008 sourceNot checked yet

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May combine two claims. The quote only partly states this claim.

The absence of relationships between individual differences in amygdala reactivity and amount of MBSR practice may indicate an all-or-nothing short-term effect of MBSR exposure, while long-term changes may depend more on practice dosage.

“Moreover, the lack of relationships between individual differences in amygdala reactivity and the amount of MBSR practice (e.g. variation in the degree to which participants engaged in at-home practice, or ‘homework’ during MBSR) may also indicate an important distinction between short- and long-term practice: it may be that there is a more “all-or-nothing” effect of exposure to MBSR in terms of”

Probably not a substantial claim: may not pass S3 (load-bearing).

Recent evidence indicates that behavioral measures of mindfulness are associated with reduced attentional capture by rewarding stimuli.

“Recent evidence that behavioral measures of mindfulness were associated with decreased attentional capture to rewarding stimuli provide additional evidence for this interpretation (Levinson et al., 2014).”

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The relationship between retreat practice hours and reduced amygdala reactivity, but not connectivity, supports the idea that increased connectivity occurs only earlier in practice and fits a nonlinear dosage-response curve.

“The fact that we found a relationship between hours of retreat practice and reduced amygdala reactivity, but not with amygdala-VMPFC connectivity lends further support to the idea that increased connectivity may only occur at earlier stages of practice, and fits with the nonlinear dosage-response curve of mindfulness meditation training (Brefczynski-Lewis et al., 2007).”

• cites Brefczynski-Lewis et al., 2007 sourceNot checked yet

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May combine two claims.

Taken together, the findings provide novel evidence that mindfulness meditation training alters the neural circuitry of automatic emotion regulation, possibly beginning early through VMPFC-amygdala connectivity changes.

“Taken together, these findings provide novel evidence that training in mindfulness meditation alters the neural circuitry of automatic emotion regulation, which may be instantiated early on by modulating connectivity between the VMPFC and amygdala.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Valence labeling likely contributed to the absence of a valence effect on later neutral-face responses, but it also likely helped assess individual differences in automatic emotion regulation during IAPS presentations.

“While the valence labeling aspect of the task likely contributed to the lack of a valence effect on the subsequent neutral face response, it also likely allowed us to more easily assess individual differences in the ability to engage with automatic (i.e. implicit) emotion regulation processes during the IAPS presentations.”

Classified as probably not a substantial claim.

The authors tried to reduce variation by recruiting long-term meditators whose practice was similar and primarily mindfulness-based.

“We attempted to minimize such variation by recruiting LTM who had similar practice that included primarily mindfulness-based meditation.”

May combine two claims.

With long-term training, reduced reactivity to affective stimuli becomes more automatic, making VMPFC recruitment less necessary.

“On this view, with long-term training the reduction in reactivity to affective stimuli becomes more automatic such that VMPFC recruitment is less necessary.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The short-term MBSR-related connectivity changes not seen in long-term meditators could also be due to other factors.

“Of course, the fact that short-term MBSR training produced alterations in amygdala-VMPFC connectivity not seen among the LTM can also be due to other factors.”

May combine two claims.

Short-term MBSR training changed amygdala-VMPFC connectivity in ways not detected in long-term meditators, suggesting a curvilinear trajectory in the neural changes needed to learn non-reactivity.

“The fact that short-term MBSR training affected amygdala-VMPFC functional connectivity in ways that we did not detect in participants with long-term training is revealing and implies a curvilinear trajectory in the neural changes required for learning the skill of non-reactivity.”

May combine two claims.

The present study provides evidence that long- and short-term mindfulness meditation training improves automatic emotion regulation and identifies neural correlates of that improvement.

“The present study provides evidence that long and short-term training in mindfulness meditation improves automatic emotion regulation and elucidates the neural correlates of this improvement.”