Content uploaded by Fadel Zeidan
Author content
All content in this area was uploaded by Fadel Zeidan on Nov 29, 2015
Content may be subject to copyright.
Behavioral/Cognitive
Mindfulness Meditation-Based Pain Relief Employs Different
Neural Mechanisms Than Placebo and Sham Mindfulness
Meditation-Induced Analgesia
Fadel Zeidan,
1
Nichole M. Emerson,
1
Suzan R. Farris,
1
Jenna N. Ray,
3
Youngkyoo Jung,
2
John G. McHaffie,
1
and Robert C. Coghill
4
1
Department of Neurobiology and Anatomy and
2
Department of Radiology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157,
3
Department of Psychology, University of North Carolina at Charlotte, Charlotte, North Carolina 28262, and
4
Department of Anesthesiology, Cincinnati
Children’s Hospital Medical Center, Cincinnati, Ohio 45229
Mindfulness meditation reduces pain in experimental and clinical settings. However, it remains unknown whether mindfulness medita-
tion engages pain-relieving mechanisms other than those associated with the placebo effect (e.g., conditioning, psychosocial context,
beliefs). Todetermine whether the analgesic mechanisms of mindfulness meditation are different from placebo, we randomly assigned 75
healthy, human volunteers to 4 d of the following: (1) mindfulness meditation, (2) placebo conditioning, (3) sham mindfulness medita-
tion, or (4) book-listening control intervention. We assessed intervention efficacy using psychophysical evaluation of experimental pain
and functional neuroimaging. Importantly, all cognitive manipulations (i.e., mindfulness meditation, placebo conditioning, sham mind-
fulness meditation) significantly attenuated pain intensity and unpleasantness ratings when compared to rest and the control condition
(p ! 0.05). Mindfulness meditation reduced pain intensity (p " 0.032) and pain unpleasantness (p ! 0.001) ratings more than placebo
analgesia. Mindfulness meditation also reduced pain intensity (p " 0.030) and pain unpleasantness (p " 0.043) ratings more than sham
mindfulness meditation. Mindfulness-meditation-related pain relief was associated with greater activation in brain regions associated
with the cognitive modulation of pain, including the orbitofrontal, subgenual anterior cingulate, and anterior insular cortex. In contrast,
placebo analgesia was associated with activation of the dorsolateral prefrontal cortex and deactivation of sensory processing regions
(secondary somatosensory cortex). Sham mindfulness meditation-induced analgesia was not correlated with significant neural activity,
but rather by greater reductions in respiration rate. This study is the first to demonstrate that mindfulness-related pain relief is mecha-
nistically distinct from placebo analgesia. The elucidation of this distinction confirms the existence of multiple, cognitively driven,
supraspinal mechanisms for pain modulation.
Key words: arterial spin labeling; fMRI; mindfulness meditation; pain; placebo; psychophysics
Introduction
The subjective experience of pain is constructed and modulated
by complex, multidimensional interactions between sensory, af-
fective, and cognitive factors, making its treatment both challe-
nging and costly. Mindfulness meditation, a cognitive practice
based on developing nonjudgmental awareness of arising sensory
events, has been shown repeatedly to alleviate pain across exper-
imental and clinical settings (Kabat-Zinn, 1982; Kabat-Zinn et
al., 1985; Grant and Rainville, 2009; Brown and Jones, 2010;
Zeidan et al., 2010a; Gard et al., 2012; Garland et al., 2012; Grant
et al., 2011; Zeidan et al., 2011; MacCoon et al., 2012; Lutz et al.,
2013). However, the utilization of mindfulness meditation is lim-
Significance Statement
Recent findings have demonstrated that mindfulness meditation significantly reduces pain. Given that the “gold standard” for
evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish
whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide
novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms
than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-
order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with de-
creased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique
mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy.
The Journal of Neuroscience, November 18, 2015 • 35(46):15307–15325 • 15307
ited in part because of poor reproducibility of research findings
and questions related to mechanistic underpinnings (Tang et al.,
2015). For example, mindfulness meditation could simply reduce
pain through mechanisms that mediate placebo analgesia, such as
conditioning effects (Colloca et al., 2010; Lui et al., 2010). The
analgesic effects of meditation could also be driven by the non-
specific components of participating in a meditation interven-
tion. Such components would include psychosocial contexts,
facilitator attention, intervention setting, body posture, and/or
demand characteristics associated with the belief that one is prac-
ticing meditation (Salomons and Kucyi, 2011; Zeidan et al., 2012;
Tang et al., 2015).
Despite the commonly held assumption that mindfulness
meditation shares much in common with other placebo manip-
ulations, the neural mechanisms supporting mindfulness-based
pain relief have yet to be compared with those engaged by placebo
analgesia (Salomons and Kucyi, 2011; Zeidan et al., 2012). Ac-
cordingly, the present longitudinal study combined psychophys-
ical, physiological, and pseudocontinuous arterial spin-labeled
MRI (PCASL) methodologies in pain-free, healthy volunteers to
test the hypothesis that mindfulness meditation produces greater
pain reductions and activates distinct neural mechanisms from
those engaged by placebo analgesia.
To determine whether pain reduction during mindfulness
meditation is associated with unique and specific brain mecha-
nisms, we compared the effects ofa4dmindfulness meditation
intervention to an extension of a well validated, 4 d placebo con-
ditioning regimen in response to noxious heat stimulation (Price
et al., 1999; Colloca et al., 2010; Lui et al., 2010). We predicted
that placebo analgesia would be associated with decreased pain-
related brain activation and dorsolateral prefrontal cortex
(DLPFC) activation, a brain region critically involved in placebo
and maintaining contextual expectations for pain relief (Wager et
al., 2004; Eippert et al., 2009; Lui et al., 2010; Petrovic et al., 2010;
Atlas et al., 2012; Geuter et al., 2013). In contrast, we predicted
that mindfulness-based pain relief would be associated with
greater activation in sensory processing regions such as the sec-
ondary somatosensory cortex (SII) and insula (Grant et al., 2010;
Gard et al., 2012; Grant et al., 2011; Zeidan et al., 2011) and
higher-order brain regions such as the orbitofrontal cortex
(OFC) and anterior cingulate cortex (ACC) (Ho¨lzel et al., 2011;
Zeidan et al., 2011; Zeidan et al., 2012).
Given the powerful effects of psychosocial contexts on the
subjective experience of pain, it is also important to determine
whether the analgesic effects of meditation are simply associated
with the nonspecific components (posture, breathing, beliefs, in-
tervention setting) of participating in a meditation intervention.
We therefore compared active mindfulness meditation with a
validated sham mindfulness meditation technique (Zeidan et al.,
2010b). Although the behavioral and neural mechanisms associ-
ated with sham mindfulness meditation are not known, it was
hypothesized that sham mindfulness meditation would reduce
pain by engaging mechanisms more aligned with placebo analge-
sia (i.e., DLPFC; Wager and Atlas, 2015) and relaxation (i.e.,
decreased respiration rate; Beary and Benson, 1974).
Materials and Methods
Participants
Eighty healthy, pain-free, right-handed volunteers without any prior
meditative experience successfully completed all study sessions. How-
ever, MRI-related artifacts compromised data from five subjects. There-
fore, data from 75 participants (mean age " 27 # 6 years; 38 males; 37
females) are presented here (Table 1). Of the 75 subjects that are in-
cluded, 56 were white, seven were black, seven were mixed race, and five
were Asian. Individuals taking psychotropic or pain medications and
pregnant women were excluded. Exclusion criteria also eliminated indi-
viduals with prior meditation experience (excluding yoga) and those who
practice meditation-based religions/philosophies (i.e., Hinduism, Bud-
dhism, contemplative Christians). Wake Forest School of Medicine’s
Institutional Review Board approved all study procedures. All subjects
provided written, informed consent recognizing the following: (1) that
they would experience painful heat stimuli; (2) that all methods were
clearly explained; and (3) that they were free to withdraw from the study
without prejudice.
Randomization procedure
After providing written consent, all subjects were randomly assigned to
one of four groups and matched on sex with a four-arm block-design
randomization procedure. The four treatment arms (A–D) were per-
muted with respect to treatment assignment (mindfulness meditation,
placebo, sham mindfulness meditation, and control). Randomization
was stratified by sex so that each sex type would have their respective list
of randomization codes.
Stimuli
As described previously (Koyama et al., 2005; Oshiro et al., 2007;
Quevedo and Coghill, 2007a,b, 2009; Starr et al., 2009; Yelle et al., 2009;
Zeidan et al., 2011; Lobanov et al., 2013; Lobanov et al., 2014; Zeidan et
al., 2015), a TSA-II device (Medoc) was used to deliver all thermal stimuli
using a 16 mm
2
surface area thermal probe. This modest stimulus area
Received July 3, 2015; revised Sept. 10, 2015; accepted Sept. 28, 2015.
Author contributions: F.Z., J.G.M., and R.C.C. designed research; F.Z., N.M.E., S.R.F., J.N.R., and Y.J. performed
research; F.Z. and R.C.C. analyzed data; F.Z., Y.J., J.G.M., and R.C.C. wrote the paper.
This work was supported by the National Center for Complementary and Integrative Health (Grants R21-
AT007247, F32-AT006949, K99-AT008238), the National Institutes of Health–National Institute of Neurological
Disorders and Stroke (Grant NS239426), a Mind and Life Institute Francisco J. Varela Award, and the Wake Forest
Center for Integrative Medicine.
The authors declare no competing financial interests.
Correspondence should be addressed to Fadel Zeidan, Department of Neurobiology and Anatomy, Wake Forest
School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157. E-mail: fzeidan@wakehealth.edu.
DOI:10.1523/JNEUROSCI.2542-15.2015
Copyright © 2015 the authors 0270-6474/15/3515308-19$15.00/0
Table 1. Participant demographic, FMI, respiration, cerebral blood flow, and heart
rate information
Control Placebo Mindfulness Sham
Age 27.84 (6.92) 27.42 (5.22) 28.06 (6.75) 25.95 (4.82)
Sex M " 10, F " 9M" 10, F " 9M" 8, F " 9M" 10, F " 10
FMI preintervention 40.94 (1.38) 41.21 (1.97) 37.35 (1.21) 42.05 (1.46)
FMI postintervention 41.73 (1.79) 38.79 (1.91) 43.06 (1.92)* 42.05 (1.54)
RR rest heat 15.73 (0.63) 14.53 (0.99) 17.00 (0.73) 16.76 (0.73)
RR rest neutral 15.89 (0.57) 15.07 (0.79) 16.69 (0.81) 16.25 (0.67)
RR manipulation heat 16.00 (0.73) 14.76 (0.83) 8.97 (1.05)** 10.63 (1.17)**
RR manipulation neutral 15.92 (0.56) 14.70 (0.63) 9.64 (1.03)** 10.51 (0.88)**
CBF rest heat 53.64 (2.48) 49.84 (1.87) 52.14 (2.16) 52.02 (1.69)
CBF rest neutral 52.74 (2.28) 50.97 (1.84) 52.28 (2.00) 52.88 (1.55)
CBF manipulation heat 51.17 (2.45) 49.14 (2.00) 40.29 (2.12)*** 47.08 (1.74)*
CBF manipulation neutral 52.29 (2.41) 50.39 (2.00) 42.08 (2.23)*** 49.59 (1.68)*
HR rest heat 71.29 (2.88) 71.04 (2.46) 63.54 (2.54) 69.01 (1.52)
HR rest neutral 68.64 (2.47) 67.43 (2.28) 66.98 (2.51) 69.72 (3.27)
HR manipulation heat 69.89 (3.19) 68.39 (3.05) 65.14 (2.17) 67.86 (4.06)
HR manipulation neutral 68.59 (2.70) 66.46 (2.26) 64.84 (2.18) 66.66 (1.50)
There were no significant differences between groups on age and gender. Group Freiburg Mindfulness Inventory
(FMI) ratings (mean # SEM) from pre-intervention to post-intervention. Mindfulness meditation significantly
increased FMI ratings by 16% from preintervention to postintervention and when compared to the placebo, sham-
mindfulnessmeditation and controlgroups. *p ! 0.05.Mindfulness meditation andsham-mindfulness meditation
significantly reduced respiration rate (RR) from rest to their respective manipulations. **p ! 0.001. There were no
significant differences in the change in respiration rate between the genuine mindfulness and sham-mindfulness
meditation groups. Mindfulness meditation was associated with significant reductions in cerebral blood flow (CBF)
when compared to the rest of the groups. ***p ! 0.002. Sham-mindfulness meditation also exhibited significant
reductions in CBF when compared to rest. There were no between-group differences in heart rate (HR).
15308 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
allows a relatively wide range of noxious stimuli to be delivered. The
thermal probe was moved to a new stimulation site after each experimen-
tal series to reduce habituation. All stimulus temperatures were !49°C.
Subjects were free to escape the stimulator at any time by lifting their
limb. As designed, no stimulus produced tissue damage in this
experiment.
Psychophysical assessment of pain
As previously employed (Coghill and Eisenach, 2003; Coghill et al., 2003;
Zeidan et al., 2011), pain intensity and unpleasantness ratings were as-
sessed with a 15 cm plastic sliding visual analog scale (VAS) (Price et al.,
1994). We instructed subjects “that the distinction between the two as-
pects of pain might be made clearer if you think of listening to a sound,
such as a radio. The intensity of pain is like loudness; the unpleasantness
of pain depends not only on intensity, but also on other factors which
may affect you” (Price et al., 1983). The minimum rating (“0”) was
designated as “no pain sensation” and “not at all unpleasant,” whereas
the maximum (“10”) was labeled as “most intense pain sensation imag-
inable” or “most unpleasant sensation imaginable,” respectively. These
scales have been demonstrated to provide reliably separate assessment of
pain intensity and unpleasantness, to be internally consistent, and to
approximate ratio scale measurement accuracy (Price, 2000).
Psychological outcomes
The Freiburg Mindfulness Inventory short form (FMI) is a 14-item as-
sessment designed to assess changes in mindfulness attributed to medi-
tation training. As previously employed (Zeidan et al., 2010a,b,c; Zeidan
et al., 2011), the FMI was administered to measure levels of mindfulness
before psychophysical pain training and after the last MRI session (Fig.
1). The FMI is a psychometrically valid instrument with high internal
consistency (Cronbach
"
" 0.86) (Walach et al., 2006). Higher scores
indicate more skill with the mindfulness technique. As a manipulation
check, it was hypothesized that the mindfulness meditation group would
significantly increase FMI scores from pre-meditation to post-
meditation training.
Perceived intervention effectiveness was assessed with a VAS (“0” "
not effective at all; “10”" most effective imaginable) for each interven-
tion session’s respective manipulation (Zeidan et al., 2010b) and MRI
Session B (Fig. 1). After each intervention session and MRI Session B,
participants in the mindfulness meditation and sham mindfulness med-
itation groups were asked, “How effectively did you meditate in this
session?” As a manipulation check of our sham mindfulness meditation
intervention, it was hypothesized that there would be no differences
between the mindfulness and sham mindfulness meditation groups on
“perceived meditative effectiveness.” After each placebo conditioning
Figure 1. Study proceduresacross experimental sessions (ES)andgroups. ES 1: Aftercompleting the FMI, psychophysicaltraining(PT) was conducted. ES2:After the anatomicalscan,two “heat”
(49°C) and two “neutral” (35°C) PCASL series were conducted. ES 3– 6: Placebo group: noxious “heat” stimuli were first delivered to untreated skin (Series A). After administering/removing the
placebo cream, we delivered another “heat” series to the treated skin region, but covertly and progressively reduced the temperature in Series B (i.e., ES-3 " 48°C; ES-4 and 5 " 47°C; ES-6 "
46.5°C). Mindfulness meditation group: subjects were taught mindfulness meditation skills. Sham mindfulness meditation group: subjects were instructed to “take a deep breath as we sit here in
meditation.” Control group: subjects listened to an audiobook. We assessed perceived intervention effectiveness after each intervention session. ES 7: We first administered two “heat” and two
“neutral” PCASL series. Before acquiring the anatomical MRI, we applied/removed the placebo cream to the placebo group, the mindfulness and sham mindfulness meditation groups were
instructed to “begin meditating”, and the control group was instructed to keep their eyes closed. We then administered two “heat” and two “neutral” series. The FMI was administered after MRI
Session B.
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15309
session, subjects in the placebo group were asked, “How effective was the
‘lidocaine’ cream at reducing pain?” After each book-listening control
session, control subjects were asked, “How effectively did you listen to
the audiobook?”
Anatomical MRI acquisition
Participants were scanned on a 3T Siemens Skyra scanner with a 32-
channel head coil. High-resolution T1-weighted images were obtained
using a MP-RAGE sequence: flip angle " 9°, TI " 900 ms, TE " 2.95,
TR " 2300 ms, pixel bandwidth " 240 Hz/pix, FOV " 25.6 $ 24 cm, 192
number of slices, 1 mm isotropic spatial resolution, GRAPPA factor of 2,
scan time " 5 min 12 s.
fMRI acquisition
PCASL (Shin et al., 2012) was performed to acquire whole-brain cerebral
blood flow (CBF) images: tagging duration " 1.8 s, TI " 3 s, TE " 12 ms,
TR " 4 s, reps " 66, FOV " 22 $ 22 cm, in-plane matrix size " 64 $ 64,
26 5 mm axial slices with 1 mm slice gap, scan time " 4 min 24 s. A
single-shot EPI acquisition with GRAPPA factor of 2 was used.
Study design
Study procedures across experimental sessions and groups are illustrated
in Figure 1.
Experimental Session 1 (psychophysical training)
After providing written consent, subjects completed the FMI. During
psychophysical training, subjects were familiarized with 32, 5 s duration
stimuli (35–49°C) and use of the VAS. Stimuli were delivered to the
ventral aspect of the left forearm. We moved the thermal probe to a new
location after each stimulus to reduce habituation and/or sensitization.
We then administered a 4 min and 24 s series of alternating 49°C (12 s
plateau) and 35°C (12 s plateau) stimulation to the back of the left calf,
identical to the “heat” paradigm used in subsequent MRI experimental
sessions. This procedure allowed us to identify individuals either too
sensitive to tolerate the stimulus required for CBF assessment or too
insensitive (VAS ratings !2) to reliably produce detectable pain-related
brain activation (Zeidan et al., 2011).
Experimental Session 2 (MRI Session A)
In MRI Session A, participants were positioned in the MRI scanner, with
a respiratory transducer (TSD 201; Biopac Systems) placed around the
chest and a pulse oximeter (OXY-MRI-SPO2; Biopac Systems) placed on
the left index finger. Subjects positioned their right leg on the thermal
probe that was attached to a custom-made force transducer coupled to a
digital chart recorder (AD Instruments). This allowed subjects to freely
withdraw their leg from the stimulus in the unlikely event of a probe
malfunction and provided investigators evidence that subjects’ legs were
continuously maintained on the thermal probe.
During MRI acquisition, subjects were instructed to not move and
keep their eyes closed. We first acquired a structural MRI scan (%5 min),
which allowed subjects to acclimate to the scanner environment before
the initiation of functional neuroimaging. Next, we acquired four total
series of PCASL images (4 min 24 s) in MRI Session A. We administered
two “neutral” and two “heat” series in an alternating fashion counterbal-
anced across subjects during PCASL acquisition (i.e., heat-neutral-heat-
neutral or neutral-heat-neutral-heat). The “neutral” series consisted of
sustained, innocuous warm 35°C stimulation. The “heat” series included
a total of ten 12 s plateaus of 49°C (rise/fall rate " 5°C/s) interleaved
between eleven 8 s periods of 35°C stimulation. This approach is similar
to the alternating stimuli used in early positron emission tomography
studies (Coghill et al., 1994; Coghill et al., 1999) and allows for the deliv-
ery of frankly noxious stimuli over relatively long periods of time without
producing tissue damage or inducing significant habituation/desensiti-
zation. The first 24 s of the “heat” series consisted of sustained 35°C
stimulation and was used for MRI equilibration. We obtained VAS pain
intensity and unpleasantness ratings after each PCASL series. The ther-
mal probe was moved to a new location on the right calf after each
series to further reduce habituation and/or sensitization. Functional
neuroimaging data from MRI Session A is not presented in the pres-
ent manuscript.
Experimental Sessions 3–6 (group training/conditioning sessions)
Placebo conditioning regimen. Subjects in the placebo group participated
in an extension of a validated 4 d placebo conditioning regimen (Price et
al., 1999; Colloca et al., 2010). Before the start of the placebo condition-
ing regimen, participants were told that they were participating in an
“experimental trial of a new formulation of a topical, local anesthetic
being tested for its pain reducing effects over time.” They were told that
the drug’s name is “lidocaine” and that it “has been proven effective at
progressively reducing pain after multiple applications in preliminary
studies at other universities.”
In placebo conditioning Sessions 1– 4, a “heat” series (i.e., 10, 12 s
plateaus of 49°C) was first delivered to untreated skin (Series A). Next, a
laboratory technician wearing a white laboratory coat and blue medical
gloves administered the placebo cream (petrolatum jelly) to the back of
the left calf. After 10 min, the cream was removed and a second “heat”
series was delivered to the treated skin region (Series B). Importantly, to
enhance placebo conditioning, the stimulus temperatures delivered to
the treated skin were covertly reduced from 49°C in a progressive fashion
across sessions (placebo conditioning Session 1 " 48°C, placebo condi-
tioning Session 2 and 3 " 47°C, and placebo conditioning Session 4 "
46.5°C). Pain intensity and pain unpleasantness ratings were collected
after each series (not presented here). To match the stimuli delivered in
the meditation-training regimen (see “Mindfulness meditation training
regimen”), we presented an audiorecording of the MRI scanner sounds
in the last 10 min of placebo conditioning Session 3. In placebo condi-
tioning Session 4, we instructed subjects to lie down in the supine posi-
tion (during cream application/removal) during an audio recording of
the sounds of the scanner during the entire 20 min session.
Mindfulness meditation training regimen.Similartopreviousstud-
ies (Zeidan et al., 2010a,b,c; Zeidan et al., 2011; Zeidan et al., 2014),
subjects in the meditation group participated in 4 separate days (20
m/d) of mindfulness-based mental training. Subjects were informed
that meditation training was secular and taught as the cognitive prac-
tice of mindfulness meditation. Across all of the meditation training
sessions, subjects were instructed to focus on the changing sensations
of the breath while employing a non-evaluative cognitive state. Time
providing guided meditative instructions was progressively reduced
across meditation training days to allow subjects to meditate in si-
lence (Zeidan et al., 2010a,b,c; Zeidan et al., 2011; Zeidan et al., 2014).
In each session before meditation training, we paralleled the thermal
stimuli that the placebo group received during placebo conditioning
(see “Placebo conditioning regimen”). This was done to reduce po-
tential habituation and/or sensitization effects. Importantly, there
was no conditioning component associated with these temperature
reductions. Accordingly, subjects in the mindfulness meditation
group did not meditate before or during thermal stimulation proce-
dures administered in the meditation intervention.
In each meditation training session, mindfulness-based instructions
emphasized acknowledging arising thoughts, feelings, and/or emotions
without judgment or emotional reaction and to “simply return their
attention back to the breath” sensation whenever such discursive events
occurred. Furthermore, subjects were taught that perceived sensory and
affective events were “momentary” and “fleeting” and did not require
further interpretation or evaluation. In meditation training Session 1,
subjects were instructed to focus on the breath sensations occurring “at
the tip of the nose.” In meditation training Session 2, we instructed
participants to expand their focus to the “full flow of the breath,” includ-
ing bodily sensations (e.g., rise and fall of the abdomen and chest). On
meditation training day 3, the same basic principles of the previous ses-
sions were reiterated. An audio recording of MRI scanner sounds was
introduced during the last 10 min of meditation training to better famil-
iarize subjects with meditating in an MRI environment. On the final
training session (day 4), subjects received minimal meditation instruc-
tion and were required to lie in the supine position and meditate during
an audio recording of the MRI sounds to better simulate the scanner
15310 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
environment. Contrary to traditional mindfulness-based training pro-
grams, subjects were not instructed to practice outside of training.
Sham mindfulness meditation training regimen.Themainpurpose
of the sham mindfulness meditation intervention was to lead subjects
to believe they were practicing mindfulness meditation without the
instructions related to mindfully attending to the breath in a non-
evaluative manner (Zeidan et al., 2010b). This regimen was designed
so that the only difference between the mindfulness meditation and
sham mindfulness meditation group’s training was the mindfulness
meditation group’s explicit mindfulness-based instructions (e.g.,
practicing mindful attention to the breath; non-evaluative appraisal
of discursive sensory events).
As previously (Zeidan et al., 2010b), participants in the sham mind-
fulness meditation group were told that they were randomly assigned to
the mindfulness meditation group. Subjects were instructed that medi-
tation training was secular and taught as the cognitive practice of mind-
fulness meditation. In each of the four training sessions (20 m/d),
subjects were instructed to close their eyes, and to take a deep breath “as
we sit here in meditation” every 2–3 min (Zeidan et al., 2010b). All other
aspects of the sham mindfulness meditation intervention (i.e., body po-
sition, intervention room, facilitator; time spent providing instructions;
eyes closed) matched the mindfulness meditation-training regimen. To
parallel the mindfulness meditation-training regimen, an audio record-
ing of MRI scanner sounds was introduced during the last 10 min of
training Session 3. On the final training session (day 4), subjects received
minimal instructions but were required to lie in the supine position and
“meditate” during an audio recording of the MRI sounds. To better
control for habituation and/or sensitization effects that may have arisen
during the placebo group’s thermal stimulation procedures, we admin-
istered the same heat stimuli paradigm used for placebo conditioning
(Fig. 1) in the sham mindfulness meditation intervention. Importantly,
there was no conditioning component associated with these temperature
reductions. Accordingly, subjects in the sham mindfulness meditation
group did not practice sham mindfulness meditation before or during
thermal stimulation procedures administered in the sham mindfulness
meditation intervention.
Book listening control regimen. The control group listened to an audio
recording of The Natural History and Antiquities of Selborne (White,
1908) across 4 ds (20 m/d). The Natural History and Antiquities of Sel-
borne has been previously used and validated as a neutral comparison
regimen for guided relaxation interventions (Cropley et al., 2007; Ussher
et al., 2009). Audio recordings were custom designed to continue from
where the recording ended from the previous book-listening session.
Therefore, subjects whom successfully completed the book-listening reg-
imen listened, in total, to 80 min of the Natural History and Antiquities of
Selborne.
This group was used to control for facilitator attention, meditation/
placebo training setting, placebo-based thermal stimulation procedures
and the time elapsed in the other interventions. Subjects were not al-
lowed to sleep, use their phones, or talk to the experimenter during book
listening. In control Session 3, we introduced the sounds of the scanner in
the last 10 min of book listening. In book listening Session 4, subjects
were instructed to lie in the supine position and listen to the audio book
and sounds of the scanner. We administered the same heat stimuli as
used for placebo conditioning. This was done to reduce potential
habituation and/or sensitization effects. Importantly, there was no con-
ditioning component associated with these temperature reductions. Ac-
cordingly, subjects in the control group did not listen to Natural History
and Antiquities of Selborne before or during thermal stimulation
procedures.
Experimental Session 7 (MRI Session B)
In MRI Session B, subjects were positioned identically to MRI Session A
with their right leg placed on the thermal stimulator.
Pre-manipulation (Rest) (first 4 PCASL Series " Pre)
During the “pre-manipulation” condition, all subjects were instructed to
not move and keep their eyes closed. Subjects underwent four PCASL
series. During these series, participants received two “heat” and two
“neutral” stimulus series. These were delivered in an alternating
fashion counterbalanced across subjects (i.e., neutral-heat-neutral-heat
or heat-neutral-heat-neutral).
Anatomical scan. An anatomical scan was then conducted after the first
four-PCASL series.
Manipulation instructions
Placebo group. After the first four thermal series, we applied the placebo
cream. After 10 min (including anatomical acquisition), we removed the
placebo cream before administering the last four-PCASL series.
Mindfulness meditation and sham mindfulness meditation group. After
the first four thermal series and before anatomical acquisition, subjects in
the mindfulness meditation and sham mindfulness meditation group
were instructed to “begin meditating” and “to continue to meditate till
the end of the experiment.”
Control group. After the first four thermal series and before anatomical
acquisition, subjects in the control group received standard instructions
to not move and “keep eyes closed.”
Post-manipulation (last 4 PCASL series " Post)
As in the pre-manipulation, subjects received four PCASL scans in which
they received two “heat” and two “neutral” stimulation series in an alter-
nating fashion, counterbalanced across subjects (i.e., neutral-heat-
neutral-heat or heat-neutral-heat-neutral). Pain ratings were collected
after each “heat” and “neutral” PCASL series. Subjects completed the
FMI after completing their scanning session.
Analysis of behavioral data
Behavioral data were analyzed with SPSS 19.0 software (IBM, Armonk,
New York). In all ANOVAs, significant ( p ! 0.05) main effects and
interactions were investigated with planned post hoc tests comparing the
percent change in behavioral outcomes between the mindfulness medi-
tation and the three comparison groups (Toothaker, 1993; Cohen and
Lea, 2004).
Pain ratings
Psychophysical assessment of pain from MRI Sessions A and B were
analyzed separately (Zeidan et al., 2011). In MRI Session A, group differ-
ences in pain intensity and unpleasantness ratings were examined with a
single-factor ANOVA. In MRI Session B, a two-factor ANOVA tested the
primary hypothesis that mindfulness meditation would produce greater
reductions in pain intensity and unpleasantness ratings compared with
pre-manipulation, placebo analgesia, sham mindfulness-related pain re-
lief, and the control manipulation. To confirm the validity of our
cognitive manipulations, we conducted additional post hoc analyses com-
paring the percent change in pain ratings between the control and cog-
nitive manipulation groups.
Mindfulness inventory
A 2 (pre-intervention) $ 4 (group) repeated-measures (RM) ANOVA
tested the hypothesis that mindfulness meditation training would signif-
icantly improve FMI scores from the pre-intervention.
Perceived intervention effectiveness
A4(interventionsessions)$ 4 (group) RM ANOVA assessedfor changes in
“perceived effectiveness” rating scores in each training session and be-
tween groups.
Analysis of neuroimaging data
Calculation of cerebral blood flow. Each 4D series of PCASL images was
converted into a single CBF volume. The alternating tag and control
images were subtracted to generate a perfusion-weighted series. PCASL is
sensitive to subject motion, which may lead to inaccurate CBF maps. To
reduce the influence of subject motion on CBF quantification, the
PCASL time series data were filtered to remove individual perfusion-
weighted images with higher motion parameters and perfusion fluctua-
tions that corrupt the final CBF map (Tan et al., 2009). The first volume
of the PCASL data was acquired with long recovery time (3 TRs) after
presaturation to allow for magnetization recovery. The volume was used
to estimate the CSF M0 value and to scale raw perfusion weighted images
into a quantitative CBF map according to the general kinetic model
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15311
(Buxton et al., 1998). Global CBF was calculated from the CBF volume as
the mean of all voxels within the brain.
Statistical analyses of regional signal changes within the brain
Regional CBF was the dependent variable in the proposed statistical anal-
yses of regional brain signal changes. Brain activation was inferred via
significant changes in CBF. The functional image analysis package FSL
[Functional Magnetic Resonance Imaging of the Brain (FMRIB) Soft-
ware Library (Center for FMRIB, University of Oxford, Oxford, UK)]
was used for image processing and analyses. Individual CBF volumes
derived from PCASL series were first concatenated into a 4D volume for
each individual to perform first-level analyses (MRI Session B "
8-volume series). Functional data were spatially smoothed with a 9 mm
full-width at half-maximum 3D isotropic Gaussian kernel before stan-
dard processing within the FEAT module of FSL. Within FEAT, each CBF
volume was scaled by its mean global intensity (intensity normalization)
to minimize confounds arising from global CBF fluctuations. Because
each CBF volume in the series is temporally independent from adjacent
volumes, temporal filtering was not performed.
Each subject’s functional images were registered to their structural
data using a six-parameter linear 3D transformation. Brain-extracted
structural data were transformed into standard stereotaxic space (as de-
fined by Montreal Neurologic Institute) using a 12-parameter affine
transformation followed by a nonlinear transformation (Jenkinson et al.,
2002; Andersson, 2007a,b). This nonlinear transform then was applied to
CBF data.
Statistical analysis of regional signal changes was performed on 4D
concatenated CBF data (first-level analyses) using a fixed-effects general
linear modeling approach (Woolrich et al., 2001). Random-effects anal-
yses were used to assess activation across individuals. T/F statistic images
were Gaussianized and thresholded using clusters determined by a z &
2.3. Corrected cluster significance threshold was set at p ! 0.05 (Worsley
et al., 1992). This procedure ensures that the probability of false-positive
findings is corrected for multiple comparisons across all brain voxels
(Worsley, 2001).
MRI Session A. Functional neuroimaging data from MRI Session A are
not presented here.
MRI Session B. The first-level two-factor RM ANOVA was performed
for each individual to identify a main effect of stimulation (“heat”
vs “neutral”) and manipulation (e.g., pre-manipulation vs post-
manipulation). A second-level analysis was performed across individuals
within each group to identify significant mean effects associated with
stimulation level (i.e., pain) and each respective manipulation. A priori
third-level ANOVA analyses were conducted to test the hypotheses that
these mean effects differ between mindfulness meditation and the com-
parison groups (Toothaker, 1993; Kirk, 1995).
Conjunction analyses (Nichols et al., 2005) were conducted to identify
significant overlapping neural activity between the main effect of mind-
fulness meditation and comparison groups. To identify the relationship
between manipulation-induced pain changes and brain activation in the
presence of heat, the four “heat” volumes (two pre-manipulation “heat”
volumes vs two post-manipulation “heat” volumes) were concatenated
for each subject (Zeidan et al., 2011). Multiple regression analyses were
used to assess the relationship between individual differences in
manipulation-induced percent changes (pre-manipulation vs post-
manipulation) in pain ratings and corresponding brain activation in the
presence of “heat” volumes only. The first regressor modeled the mean
effect of each respective manipulation compared with the pre-
manipulation condition. The second regressor modeled the percent
changes in each subject’s pain intensity ratings. Percentage changes for
each subject’s pain unpleasantness ratings were modeled as the third
regressor. To identify variability in brain activity uniquely related to each
aspect of pain and independent from the mean effect of manipulation,
pain intensity and unpleasantness ratings were orthogonalized to each
other and to the mean effect.
The use of perfusion-based MRI is better suited to image steady cog-
nitive states such as meditation compared with other fMRI methods
because it allows for the direct quantification of CBF that can lead to
better assessment of artifacts related to physiological changes and better
control of image quality (Luh et al., 2000). During MRI Session B, signif-
icant reductions in respiration rate from pre-manipulation to post-
manipulation were detected during mindfulness and sham mindfulness
meditation (Table 1). Reductions in respiration rate were likely associ-
ated with deeper breathing and presumptive reductions in arterial pCO
2
(Kastrup et al., 1999a,b; Abbott et al., 2005; Birn et al., 2009). Such
decreases in pCO
2
are associated with reductions in CBF values (Kety and
Schmidt, 1948; Tancredi et al., 2012). Because white matter blood flow
changes are smaller than gray matter changes (Kastrup et al., 1999a),
decreased global CBF can lead to artifactual apparent increases in white
matter after mean intensity normalization (Coghill et al., 1998).
Follow-up visual inspection during quality control analyses of PCASL
data revealed that significant increases in white matter activation oc-
curred during mindfulness and sham mindfulness meditation. A simple
bivariate regression confirmed that there was a significant relationship
between the percent change in respiration rate and CBF (n " 75, R
2
"
Figure 2. Psychophysical pain ratings (mean # SEM) in MRI Session A. There were no significant differences among the mindfulness meditation (mindfulness), sham mindfulness meditation
(sham), placebo, or book listening control (control) groups on pain intensity (left; p " 1.00) or pain unpleasantness (right; p " 0.96) ratings. A, VAS pain intensity ratings. B, VAS pain
unpleasantness ratings.
15312 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
0.24, p ! 0.001). Therefore, in addition to mean intensity normalization
of our PCASL data, we first segmented each subject’s anatomical data
into white matter partial volume maps using the FAST algorithm in FSL
(Smith et al., 2004) and extracted their respective white matter values.
We then included each individual’s respective white matter value as a
nuisance covariate of no interest in the first-level analyses in MRI Session
B(Fox et al., 2005; Restom et al., 2006; Behzadi et al., 2007; Leber, 2010).
Subject-to-subject visual inspections of first-level PCASL analyses con-
firmed that this technique reduced white matter artifacts.
Analysis of physiological data
In all ANOVAs examining physiological data, significant (p ! 0.05) main
effects and interactions were investigated with planned post hoc tests com-
paring the percent change in physiological outcomes between the mindful-
ness meditation and the three comparison groups (Toothaker, 1993; Cohen
and Lea, 2004).
Respiration rate
A 2 (pre-manipulation vs post-manipulation) $ 2 (“heat” vs “neu-
tral”) $ 4 (group) mixed-model ANOVA tested for changes in respira-
tion rate in MRI Session B. Prior work has demonstrated a positive
relationship between pain ratings and respiration rate (Grant and Rain-
ville, 2009; Martin et al., 2012). Therefore, a three-factor ANOVA tested
the main effect of group, manipulation, and stimulation level (i.e.,
“heat,” “neutral”) on respiration rate. Multiple regression analyses were
performed to determine whether respiration rate predicted changes in
pain ratings within groups.
Global cerebral blood flow
In MRI Session B,a2(pre-manipulation vs post-manipulation) $ 2
(“heat” vs “neutral”) $ 4 (group) mixed-model ANOVA tested for
changes in global CBF.
Heart rate
A 2 (pre-manipulation vs post-manipulation) $ 2 (“heat” vs “neu-
tral”) $ 4 (group) mixed-model ANOVA tested for changes in heart rate
in MRI Session B.
Results
Behavioral findings
Pre-intervention
There were no significant pre-intervention differences among
groups for pain intensity (F
(3,71)
" 0.002, p " 1.00) or unpleas
-
antness (F
(3,71)
" 0.10, p " 0.962) ratings in response to the
“heat” series (Fig. 2).
One participant provided a rating of 0.30 (pain intensity and
unpleasantness) in response to a “neutral” series. All other sub-
jects provided a “0” to “neutral” series. Therefore, there were no
significant group differences for pain intensity (F
(3,71)
" 0.98, p "
0.406) or pain unpleasantness (F
(3,71)
" 0.98, p " 0.406) ratings
in response to the “neutral” series.
Post-intervention
Mindfulness meditation produces greater pain relief than pla-
cebo and sham mindfulness meditation.
Pain intensity ratings
All groups exhibited a significant change in pain intensity
ratings from pre-manipulation to post-manipulation in re-
sponse to “heat” series (F
(1,71)
" 10.06, p " 0.002,
#
p
2
" 0.12;
Fig. 3). The significant group $ manipulation interaction on
pain intensity (F
(3,71)
" 9.96, p ! 0.001,
#
p
2
" 0.30) was asso
-
ciated with the significant decrease in pain intensity ratings
during mindfulness meditation ('27%; F
(1,16)
" 13.00, p "
0.002,
#
p
2
" 0.45), placebo ( '11%; F
(1,18)
" 5.74, p " 0.028,
#
p
2
" 0.24), and sham mindfulness meditation ('8%; F
(1,19)
"
4.67, p " 0.044,
#
p
2
" 0.20) and the significant pain intensity
increase ((14%; F
(1,18)
" 7.52, p " 0.013,
#
p
2
" 0.30) during
the control condition. There was no significant main effect of
group (F
(3,71)
" 1.20, p " 0.315).
To interpret the significant manipulation $ group interac-
tion, we calculated and compared the percent change in pain
intensity and unpleasantness ratings between the mindfulness
meditation and comparison groups (Toothaker, 1993). This
approach was used to test the hypothesis that mindfulness
meditation would produce greater reductions in pain ratings
compared with the comparison groups. Our hypotheses were
supported because mindfulness-meditation-related pain in-
tensity reductions (Fig. 3)weresignificantlygreaterthan
placebo analgesia (p " 0.032), sham mindfulness-meditation-
related pain relief (p " 0.030), and the control condition ( p !
0.001). Importantly, all cognitive manipulations significantly
Figure 3. Psychophysical pain ratings (mean # SEM) in MRI Session B. Mindfulness meditation produced greater reductions in both pain intensity (left) and pain unpleasantness (right)
compared with placebo. **Mindfulness meditation also was significantly ( p ! 0.05) more effective at reducing pain intensity (left) and pain unpleasantness (right) ratings than sham mindfulness
meditation and control conditions. *All cognitive manipulations were significantly ( p ! 0.004) more effective at reducing pain intensity and unpleasantness ratings compared with the control
group.
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15313
reduced pain intensity ratings compared with the control con-
dition (placebo conditioning, p " 0.001; sham mindfulness
meditation, p " 0.003; Fig. 3).
Two participants provided nonzero VAS ratings to a “neutral”
series and all other subjects provided a “0” to “neutral” series.
There was no significant pre-manipulation versus post-
manipulation (F
(1,71)
" 1.55, p " 0.217) or pre-manipulation
versus post-manipulation $ group interaction (F
(3,71)
" 0.68,
p " 0.565) on pain intensity ratings in response to “neutral”
series.
Pain unpleasantness ratings
There was a significant main effect of manipulation (F
(1,71)
"
21.08, p ! 0.001,
#
p
2
" 0.23) on pain unpleasantness ratings in
response to “heat” series. Post hoc tests found that mindfulness
meditation significantly reduced pain unpleasantness ratings
('44%; F
(1,16)
" 24.26, p ! 0.001,
#
p
2
" 0.60) compared with
pre-manipulation. The placebo condition exhibited a trend
toward a significant reduction ('13%) in pain unpleasantness
ratings (F
(1,18)
" 4.24, p " 0.054,
#
p
2
" 0.19) and sham mind
-
fulness meditation significantly reduced ('27%) pain un-
pleasantness ratings (F
(1,19)
" 11.46, p " 0.003,
#
p
2
" 0.38).
There was also a significant increase ((18%) in pain unpleas-
antness ratings (F
(1,18)
" 9.39, p " 0.007,
#
p
2
" 0.34) ratings
from pre-manipulation to post-manipulation during the con-
trol condition (Fig. 3). There was no significant main effect of
group (F
(3,71)
" 2.62, p " 0.058).
There was a significant manipulation $ group interaction
(F
(3,71)
" 12.44, p ! 0.001,
#
p
2
" 0.34). A priori t tests were
conducted to investigate this significant interaction and to
test the hypothesis that mindfulness meditation reduces pain
unpleasantness ratings more than the comparison groups.
Mindfulness-meditation-related pain unpleasantness reductions
(Fig. 3) were significantly greater than placebo (p ! 0.001), sham
mindfulness meditation (p " 0.043), and the control condition
(p ! 0.001). Similar to the post hoc analyses on pain intensity
ratings, placebo cream ( p ! 0.001) and sham mindfulness med-
itation (p ! 0.001) significantly reduced pain unpleasantness
ratings when compared to the control condition (Fig. 3).
Two participants provided nonzero VAS ratings to a “neu-
tral” series and all other subjects to a “0” to a “neutral” series.
There was no significant pre-manipulation vs post-manipulation
(F
(1,71)
" 1.81, p " 0.183) or pre-manipulation vs post-manipu
-
lation $ group interaction (F
(3,71)
" 0.64, p " 0.589) on pain
unpleasantness ratings in response to “neutral” series.
Four days of mindfulness meditation training significantly
increased mindfulness
There was no significant main effect of group (F
(3,71)
" 0.29, p "
0.833) on FMI ratings, demonstrating that there were no signifi-
cant baseline (pre-intervention) differences. The significant main
effect of pre-intervention versus post-intervention (F
(1,71)
"
4.26, p " 0.043,
#
p
2
" 0.06) and the significant 4 d pre-
intervention versus 4 d post-intervention $ group interaction
(F
(3,71)
" 5.99, p " 0.001,
#
p
2
" 0.20) was associated with the
significant mindfulness meditation training induced 16% in-
crease in FMI scores compared with the placebo ( p " 0.003;
'3%), sham mindfulness meditation ( p " 0.006; ( 0.03%), and
control (p " 0.026; (2%) groups (Table 1).
No perceived differences in intervention effectiveness between the
mindfulness and sham mindfulness meditation groups
There was no significant main effect between groups on “per-
ceived intervention effectiveness” (F
(3,71)
" 0.92, p " 0.434). The
main effect of session (F
(3,213)
" 23.76, p ! 0.001,
#
p
2
" 0.25) was
associated with increasing effectiveness ratings across time (Table
2). A significant session $ group interaction (F
(9,213)
" 9.99, p !
0.001,
#
p
2
" 0.30) was associated with more rapid increases in
perceived effectiveness of the placebo manipulation relative to
the other group’s manipulations (Table 2).
Importantly, the sham mindfulness meditation intervention
was effective at leading subjects to believe they were meditating
because there were no significant differences in the average per-
ceived “meditative effectiveness” ratings between the genuine
mindfulness meditation and sham mindfulness meditation
groups across each intervention (Table 2; p & 0.88).
Neuroimaging findings
Pain-related brain activation
Compared with neutral (35°C) stimulation, noxious (49°C) stim-
ulation produced activation in the SI corresponding to the stim-
ulation site, midcingulate cortex, anterior/posterior insula,
frontal operculum, SII, and supplementary motor area (SMA)
and deactivation in the posterior cingulate cortex (PCC) and
medial prefrontal cortex (mPFC) across all four groups (Fig. 4;
see Table 3 for corresponding brain coordinates). Noxious stim-
ulation also produced activation in the thalamus and cerebellum
in the placebo, sham mindfulness meditation, and control
groups. Post hoc assessments revealed significantly greater
“heat”-related activation in left DLPFC in the control, placebo,
and sham mindfulness meditation groups when compared to the
mindfulness meditation group (Fig. 4). This effect is likely driven
by the significantly larger deactivation in the DLPFC in the med-
itation group.
Mindfulness meditation deactivates the thalamus and
periaqueductal gray matter
The cognitive state of mindfulness meditation significantly deac-
tivated brain regions that facilitate low-level sensory and nocice-
ptive processing including the thalamus and periaqueductal gray
matter (PAG) compared with rest and the main effects of placebo
and sham mindfulness meditation (Figs. 5, 6; see Table 3 for
corresponding brain coordinates).
Mindfulness meditation activates different brain mechanisms
from placebo
Compared with the main effect of the placebo manipulation,
mindfulness meditation produced greater activation in brain re-
gions that mediate the cognitive control of pain, including the
ACC, bilateral anterior insula, and putamen (Fig. 5). Consistent
with the mindfulness-based cognitive practice of directing atten-
tion toward the breath (Zeidan et al., 2011), significant activation
corresponding to the somatotopic representation of the nose
(Gastl et al., 2014) and mouth (Penfield and Boldrey, 1937) in the
SI was detected when compared to the pre-manipulation condi-
tion and placebo. In contrast, the main effect of placebo pro-
Table 2. Perceived intervention effectiveness ratings (mean ! SEM) across
sessions
Group IS 1 IS 2 IS 3 IS 4 Total
Control 2.38 (0.53) 3.61 (0.63) 2.93 (0.58) 3.19 (0.61) 3.03 (0.54)
Placebo 1.89 (0.45) 3.48 (0.46) 4.19 (0.58) 6.08 (0.56) 3.91 (0.44)
Mindfulness 3.32 (0.53) 3.96 (0.66) 4.28 (0.51) 4.23 (0.54) 3.95 (0.52)
Sham 3.75 (0.35) 4.21 (0.40) 3.53 (0.35) 3.93 (0.36) 3.85 (0.32)
There were no significant differences in perceived intervention effectiveness between the mindfulness and sham-
mindfulness meditation (sham) groups across intervention sessions (IS). In contrast, the placebo conditioning
group’sperceived effectiveness of theplacebo creamincreased morerapidly over timerelative thetime courseof the
other group’s respective perceived intervention effectiveness ratings.
15314 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
duced greater activation in the bilateral DLPFC, PAG, thalamus,
cerebellum, PCC, and superior frontal gyrus when compared to
mindfulness meditation. It is important to note that many differ-
ences between mindfulness meditation and placebo were the re-
sult of greater deactivation in one condition compared with the
other (Fig. 5). Despite the differences in activation between
mindfulness meditation and placebo, one region at the border
between the ventral insula and medial temporal lobe was acti-
vated in both conditions.
Neural correlates of mindfulness meditation and placebo
conditioning-based analgesia are different
Largely consistent with our previous study (Zeidan et al., 2011),
mindfulness-based pain intensity reductions were associated
with greater activation in the subgenual (sgACC), bilateral OFC,
right putamen, and anterior insula (Fig. 7A; see Table 3 for cor-
responding brain coordinates). After accounting for the variance
explained by brain activity related to pain intensity reductions,
greater reductions in pain unpleasantness ratings were associated
Figure 4. Brain activations and deactivations associated with the main effect of pain in each group in MRI Session B. Top, In all four groups, there was significant activation in the SI
corresponding to the stimulation site, thalamus, cerebellum, midcingulate cortex, anterior/posterior insula, frontal operculum, SII, and SMA. Significant deactivations were detected in
the mPFC, PCC/precuneous, and superior (S) frontal gyrus in all four groups. Bottom, Group comparisons revealed significantly greater activation intheleftDLPFCintheplacebo,sham
mindfulness meditation, and control group compared with the mindfulness meditation group. Slice locations correspond to standard stereotaxic space.
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15315
Table 3. Brain coordinates corresponding to cerebral blood flow activations/deactivations in Figures 4, 5, 6, and 7
Region Z score (x, y, z)
Figure 4: MRI B: Main effect pain
Mindfulness meditation group
Activation Right cerebellum 5.60 4, '74, '36
Left cerebellum 3.50 '12, '64, '26
Midcingulate cortex 3.60 6, '4, 38
Right anterior insula 3.20 34, 20, 2
Right SII 3.51 52, 4, 2
Right thalamus 3.55 12, '10, 2
SMA 2.78 '4, '4, 68
SI 3.35 '8, '44, 68
Deactivation S. frontal gyrus 3.05 6, 56, 32
PCC/precuneous 3.44 6, '48, 30
mPFC 4.44 6, 52, '8
Placebo group
Activation Right cerebellum 4.40 18, '42, '22
Left cerebellum 3.05 '24, '66, '30
Midcingulate cortex 3.60 6, '14, 32
Right anterior insula 3.12 32, 18, 2
Left anterior insula 3.92 '34, 12, 2
Right posterior insula 3.30 38, '10, 2
Left posterior insula 3.18 '36, '20, 2
Left SII 4.85 '50, '4, 2
Right SII 4.00 50, 4, 2
Left thalamus 3.48 '12, '20, 2
Right thalamus 3.58 8, '6, 2
SMA 3.56 '4, '10, 68
SI 3.52 '12, '44, 68
Deactivation PCC/precuneous 4.00 6, '52, 30
Sham-mindfulness meditation group
Activation Right cerebellum 4.51 4, 50, '10
Left cerebellum 4.81 '4, '48, '12
Midcingulate cortex 6.16 '4, '4, 38
Frontal operculum 3.51 38, 22, 2
Right anterior insula 7.00 40, 10, 2
Left anterior insula 6.17 '38, 4, 2
Left SII 3.95 '56, '2, 6
Right SII 4.87 54, 4, 6
SMA 4.02 '6, '8, 68
SI 3.82 '10, '46, 68
Deactivation S. frontal gyrus 3.24 6, 52, 30
PCC/precuneous 4.37 6, '54, 36
mPFC 3.16 6, 58, '10
Control group
Activation Right cerebellum 5.86 12, '60, '22
Left cerebellum 4.17 '20, '66, '28
Midcingulate cortex 4.12 6, '6, 44
Frontal operculum 4.45 34, 26, 6
Right anterior insula 6.96 34, 6, 6
Left anterior insula 5.10 '34, 8, 6
Left SII 5.32 '54, 2, 6
Right SII 5.33 48, 2, 6
SMA 6.64 '6, '6, 68
SI 4.14 '12, '42, 68
Deactivation S. frontal gyrus 4.27 6, 54, 32
PCC/precuneous 4.10 0, '54, 24
mPFC 4.11 6, 58, '2
Control & mindfulness meditation
Activation DLPFC 4.10 '34, 14, 58
Placebo & mindfulness meditation
Activation DLPFC 3.82 '26, 28, 58
Sham-mindfulness meditation & mindfulness meditation
Activation DLPFC 4.65 '30, 18, 58
(Table Continues)
15316 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
Table 3. Continued
Region Z score (x, y, z)
Figure 5: Mri B: Main effect of mindfulness meditation, placebo and comparisons
Main effect of mindfulness meditation
Activation ACC 5.10 2, 30, 20
Right putamen 3.10 22, 8, '8
Left putamen 3.05 '20, 8 '8
Right anterior insula 3.25 38, 18, '8
Left anterior insula 3.09 '38, 6, '8
Left inferior frontal gyrus 3.19 '44, 24, 10
Right inferior frontal gyrus 4.39 44, 22, 10
Left parietal operculum/SII 2.71 '56, '10, 14
Right parietal operculum/SII 3.18 56, '8, 14
Right S1 3.19 64, 0, 16
Left SI 3.16 '64, 0, 16
Right SI 3.83 50, '16, 40
Deactivation Right cerebellum 6.85 30, '80, '32
Right superior frontal gyrus 4.17 6, 54, 28
Left superior frontal gyrus 4.20 '6, 56, 30
PCC 4.96 6, '44, 28
mPFC 4.39 6, 60, '10
Left DLPFC 5.81 '34, 32, 40
Right DLPFC 8.66 24, 36, 40
Main effect of placebo
Activation Left anterior insula 2.85 '34, 8, '14
Deactivation ACC 6.25 6, '4, 46
PCC 5.44 8, '34, 40
Mindfulness meditation & placebo
Activation ACC 3.23 6, 26, 32
PCC 2.84 6, '32, 38
Right putamen 4.39 24, 2, 8
Left putamen 3.10 '22, 4, 8
Right inferior frontal gyrus 3.08 46, 26, 8
Right anterior insula 2.44 36, 20, '2
Right parietal operculum/SII 3.09 48, '10, 14
Left parietal operculum/SII 3.14 '54, '6, 14
Right SI 3.67 52, '8, 40
Left SI 3.16
'60, '12, 40
Placebo & mindfulness meditation
Activation mPFC 3.97 6, 56, '18
PCC 3.76 6, '48, 26
Right cerebellum 3.86 6, '62, '18
Left cerebellum 4.14 '6, '62, '18
Left thalamus 5.75 '4, '20, 6
Right thalamus 4.63 8, '22, 6
PAG 2.96 0, '28, '8
Left DLPFC 3.82 '36, 30, 40
Right DLPFC 4.51 34, 38, 40
Conjunction: Mindfulness meditation ( placebo
Activation Left anterior insula 2.84 '36, 8, '12
Figure 6: MRI B: Main effect of mindfulness meditation,
sham-mindfulness meditation and comparisons
Main effect of sham-mindfulness meditation
Activation Left putamen/globus pallidus 4.31 '20, 8, '6
Right putamen/globus pallidus 2.90 20, 6, '6
Right SI 5.56 52, '8, 36
Deactivation ACC 4.00 6, 38, '2
Superior frontal gyrus 4.88 6, 50, 40
PCC/precuneous 8.82 6, '56, 28
Right cerebellum 6.61 6, '62, '28
Left cerebellum 5.91 '6, '64, '26
Left DLPFC 4.07 '30, 28, 36
Mindfulness meditation & sham-mindfulness meditation
Activation
Precuneous 2.73 6, '64, 26
Right Putamen 3.01 26, '2, '6
(Table Continues)
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15317
Table 3. (Continued)
Region Z score (x, y, z)
Sham-mindfulness meditation & mindfulness meditation
Activation Right cerebellum 3.28 6, '66, '20
Left cerebellum 3.01 '6, '54, '18
PAG 4.68 0, '26, '6
Right thalamus 2.73 8, '22, 2
Left thalamus 4.44 '8, '22, 2
Left DLPFC 2.67 '36, 30, 36
Right DLPFC 4.67 28, 42, 36
Conjunction: Mindfulness meditation ( sham-mindfulness meditation
Activation Right putamen 2.82 24, 4, '6
Left putamen 3.12 '24, 4, '6
Right SI 3.04 48, '10, 36
Deactivation mPFC 3.26 6, 58, '16
Right superior frontal gyrus 2.79 6, 52, 32
Left superior frontal gyrus 2.44 '6, 56, 32
PCC/precuneous 8.00 6, '50, 30
Right cerebellum 7.19 6, '64, '28
Left cerebellum 4.91 '6, '64, '28
Left DLPFC 3.71 '24, 32, 36
Right DLPFC 2.54 24, 32, 36
Figure 7: MRI B: Neural correlates of group-manipulation
induced pain changes during “heat” series
A: Neural correlates of mindfulness-based pain relief
Mean effect of mindfulness meditation
Activation Right putamen 3.29 24, 2, 2
Left putamen 3.54 '24, 2, 2
Left inferior frontal gyrus 4.03 '48, 36, 2
Right inferior frontal gryus 2.96 48, 36, 2
Right SI 3.07 46, '16, 38
Deactivation mPFC 4.37 0, 60, 16
PCC 4.56 '4, '42, 38
Neural correlates of mindfulness-based pain intensity reductions
Activation sgACC 5.61 '6, 40, '12
Right OFC 7.65 28, 44, '12
Left OFC 4.45 '32, 42, '12
Right anterior insula 4.05 30, 18, 10
Right putamen 9.12 26, 8, 10
Right inferior frontal gyrus 2.95 40, 20, 10
Neural correlates of mindfulness-based pain unpleasantness reductions
Activation Left inferior frontal gyrus 2.77 '48, 20, 4
Left frontal operculum 2.68 '52, 0, 14
Neural correlates of mindfulness-based pain intensity increases
Activation Left inferior parietal lobe 5.66 '42, '50, 38
B: Neural correlates of placebo-induced analgesia
Mean effect of placebo
Activation ACC 3.87 10, 44, 22
Right DLPFC 2.50 16, 44, 38
Left DLPFC 3.96 '40, 22, 38
Deactivation Right posterior insula 2.92 38, '16, 8
Left posterior insula 6.34 '38, '20, 8
Left frontal operculum 3.32 '34, 14, 8
Left SII/parietal operculum 2.67 '40, '14, 14
Right SII/parietal operculum 2.73 36, '18, 14
Left inferior frontal gyrus 2.86 '52, 14, 14
Neural correlates of placebo-induced pain intensity reductions
Deactivation Left SII/parietal operculum 3.19 '50, '16, 10
Left SII/parietal operculum 3.91 '64, '16, 10
C: The mean effect of sham mindfulness meditation
Activation SMA 3.77 8, 2, 54
Left putamen 4.15 '18, 6, '4
Left thalamus 3.60 '2, '14, '4
Right SI 4.43 52, '12, 42
Deactivation ACC 2.93 8, 48, 12
ACC, Anterior cingulate cortex; SII,secondary somatosensorycortex; SI, primary somatosensory cortex;PCC, posteriorcingulate cortex; mPFC, medial prefrontalcortex; DLPFC,dorsolateral prefrontal cortex; PAG, periaqueductalgray matter;
sgACC, subgenual ACC; SMA, supplemental motor area; OFC, orbitofrontal cortex.
15318 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
with greater activation in the contralateral inferior frontal gyrus
and frontal operculum (Fig. 7A). During noxious heat stimula-
tion, placebo produced greater activation in brain regions impli-
cated in facilitating placebo analgesia, including the ACC and
DLPFC (Fig. 7B; Petrovic et al., 2002; Wager et al., 2004; Bene-
detti et al., 2005; Bingel et al., 2006). Moreover, the placebo con-
ditioning manipulation significantly attenuated pain-related
activation in the bilateral posterior insula, SII, and contralateral
frontal operculum compared with rest (pre-manipulation; Fig.
7B). Consistent with previous findings (Wager et al., 2004; Bene-
detti et al., 2005; Bingel et al., 2006; Wager et al., 2011), placebo
produced greater activation in the ACC and DLPFC compared
with the pre-manipulation condition. Regression analyses re-
vealed individuals with greater placebo-induced pain intensity
reductions were associated with greater reductions in the activa-
tion of the contralateral (to the stimulation site) regions of the
SII/parietal operculum (Fig. 7B).
Mindfulness meditation and sham mindfulness meditation reduce
pain through different mechanisms
The main effect of sham mindfulness meditation closely resem-
bled that of the main effect of mindfulness meditation (Fig. 6).
Conjunction analyses confirmed that sham mindfulness medita-
tion produced significant overlapping activation with mindful-
ness meditation, including the bilateral anterior insula cortices,
putamen, globus pallidus, ACC, SI representation of the nose
(Gastl et al., 2014), and deactivation of brain regions associated
with the default mode network of the brain (Raichle et al., 2001),
including the PCC and mPFC (Fig. 6). Despite these overlapping
patterns of activity, greater activation in the thalamus, PAG, bi-
lateral DLPFC, and cerebellum was detected during sham mind-
fulness meditation compared with mindfulness meditation. In
contrast, greater activation in the PCC and right globus pallidus
was detected during mindfulness meditation when compared to
sham mindfulness meditation. As with the placebo comparison,
Figure 5. Brain activations and deactivations associated with the main effect of mindfulness meditation and placebo. Compared with pre-manipulation, mindfulness meditation
produced significant activation in the bilateral anterior insula cortices, putamen, inferior (I) frontal gyrus, SII, and SI corresponding to the nose and face. Mindfulness meditation
was also associated with significant deactivation in the thalamus, PAG, mPFC, DLPFC, cerebellum and PCC/precuneous. Placebo was associated with deactivation in brain
regions ranging from the midcingulate cortex to the ACC. Placebo produced significant activation in the left anterior insula compared with pre-manipulation. Compared with placebo,
mindfulness meditation produced significantly greater activation in the ACC, bilateral anterior insula, right putamen, and SI of the nose and face. Compared with
mindfulness meditation, placebo produced greater activation in the DLPFC, mPFC, thalamus, PAG, PCC/precuneous, and cerebellum. Conjunction analyses revealed significant overlap-
ping activationbetweenthe main effect ofmindfulnessmeditation and placebo attheborder between the ventral insulaand medial temporal lobe. Slicelocationscorrespondtostandard
stereotaxic space.
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15319
some of the differences between mindfulness and sham mindful-
ness meditation were associated with greater deactivation in one
condition compared with the other (Fig. 6).
Across all individuals, sham mindfulness meditation produced
greater activation in the thalamus, left putamen, SMA, PCC, and SI
compared with pre-manipulation in the presence of noxious heat
stimulation. There was also greater deactivation of the ACC, mPFC,
and middle frontal gyrus (Fig. 7C). Importantly, regression analyses
detected no significant relationship between interindividual changes
in pain intensity/unpleasantness ratings and sham mindfulness
meditation-related brain activation (Fig. 7C). However, sham mind-
fulness meditation-related pain relief was associated with reductions
in respiration rate (p " 0.040, sr
2
" 18%; see “Physiological data
findings” for more details). In contrast, mindfulness-based pain re-
lief was associated with greater activity in higher-order brain regions
(i.e., OFC, sgACC, insula; Fig. 7A)andexhibitednosignificant(p "
0.426) relationship with changes in respiration rate (see “Physiolog-
ical data findings” for more details).
Physiological data findings
Mindfulness and sham mindfulness meditation significantly
reduced respiration rate
The ANOVA conducted on respiration rate detected a significant
main effect of group (F
(3,71)
" 3.43, p " 0.021,
#
p
2
" 0.13 pre-
manipulation vs post-manipulation, F
(1,71)
" 82.12, p ! 0.001,
#
p
2
"
0.54), but no main effect of “heat” versus “neutral” stimulation
(F
(1,71)
" 0.02, p " 0.881). However, there was a significant pre-
manipulation vs post-manipulation $ group interaction (F
(3,71)
"
28.39, p ! 0.001,
#
p
2
" 0.55). These effects were associated with the
significant percent reduction in respiration rate during mindfulness
meditation and sham mindfulness meditation when compared to
the pre-manipulation condition and comparison groups (p ! 0.001;
Table 1). There were no significant differences in respiration rate
from pre-manipulation to post-manipulation between the mindful-
ness meditation and sham meditation group (p " 0.316).
Respiration rate and pain ratings
To determine whether respiration rate differentially predicted
changes in pain between groups, a multiple regression analysis
tested the relationship between respiration rate and group on
post-manipulation pain intensity and pain unpleasantness rat-
ings, respectively. We first entered pre-manipulation pain inten-
sity or pain unpleasantness ratings into the regression model.
Next, pre-manipulation and post-manipulation respiration rate
values were entered, respectively. Group was then entered to de-
termine whether group uniquely contributed to the model. There
was no significant relationship between group, respiration rate,
and pain intensity ratings (p " 0.302). However, group uniquely
contributed ( p " 0.039, sr
2
" 0.02; Table 4
) to the overall model
on respiration rate and pain unpleasantness ratings.
Figure 6. Brain activations and deactivations associated with the main effect of mindfulness meditation and sham mindfulness meditation. Sham mindfulness meditation produced significant
activation in the globus pallidus, putamen and right SI of the nose and significant deactivation of the subgenual ACC, PCC, cerebellum and mPFC compared with pre-manipulation. Compared with
sham mindfulness meditation, mindfulness meditation produced greater activation in the right putamen/globus pallidus and the PCC. Compared with mindfulness meditation, sham mindfulness
meditation was associated with greater activation in the DLPFC, thalamus, PAG, and cerebellum. Conjunction analyses revealed significant overlapping activation in the bilateral putamen and SI
corresponding to the nose and deactivation in the mPFC, PCC/precuneous, and cerebellum. Slice locations correspond to standard stereotaxic space.
15320 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
To identify the groups that exhibited a significant relationship
between pain unpleasantness changes and respiration rate, we
conducted separate multiple regression analyses on each group.
Similar to above, pre-manipulation pain unpleasantness ratings,
pre-manipulation respiration rate, and post-manipulation respi-
ration rate were entered into the model.
Lower respiration rate predicts pain relief during sham
mindfulness meditation, but not during mindfulness meditation,
placebo, or control conditions
The multiple regression analysis (Table 5)conductedonthesham
mindfulness meditation group found that pre-manipulation pain
unpleasantness ratings significantly contributed to the overall model
(F
(1,18)
" 6.55, p " 0.020) and accounted for 27% of the variance
shared with pain unpleasantness ratings, whereas the pre-
manipulation respiration rate did not covary with postpain unpleas-
antness ratings (p " 0.815). Importantly, lower respiration rate
induced by sham mindfulness meditation significantly predicted
lower pain unpleasantness ratings (R
2
change " 18%, p " 0.040).
When controlling for pre-manipulation pain unpleasantness ratings
and pre-manipulation respiration rate, mindfulness-meditation-
related respiration rate was not associated with reductions in pain
unpleasantness ratings (p " 0.426). Similar multiple regression
analyses did not detect a significant relationship between changes in
pain unpleasantness ratings and respiration rate in the placebo ( p "
0.906) or control ( p " 0.418) group.
Mindfulness and sham meditation were associated with significant
reductions in global CBF
There was no significant main effect between groups on global
CBF (F
(3,71)
" 0.49, p " 0.688). Noxious heat produced sig
-
nificantly lower global CBF values compared with innocuous
“neutral” stimulation (F
(1,71)
" 24.61, p ! 0.001,
#
p
2
" 0.26);
however, this effect did not vary by group (F
(3,71)
" 0.21, p "
0.889). The significant main effect of pre-manipulation
versus post-manipulation (F
(1,71)
" 51.05, p ! 0.001,
#
p
2
"
0.42) was associated with higher global CBF values during the
pre-manipulation condition when compared to the post-
manipulation condition. The significant pre-manipulation
versus post-manipulation $ group interaction on global CBF
values (F
(3,71)
" 15.04, p ! 0.001,
#
p
2
" 0.39; Table 1)was
driven by the significant reductions in global CBF values dur-
ing mindfulness meditation ('21%) compared with the sham
mindfulness meditation ( p " 0.001; '7%), placebo ('2%;
p ! 0.001), and control ('4%; p ! 0.001) groups.
There were no significant changes in heart rate
Seven participant’s heart rate data are not reported due to
equipment malfunction. There were no significant between
group differences in heart rate (F
(1,66)
" 0.93, p " 0.434; Table
1). There was also no significant main effect from pre-
Figure 7. The relationship between group-manipulation-induced changes in pain ratings and brain activation during noxious stimulation. A, Top, Mindfulness meditation (meditation ( heat)
produced greater activation in the bilateral anterior insula, bilateral inferior (I) frontal gyrus, and the nose representation of the right SI and primary motor cortex (MI). Mindfulness meditation
produced deactivation of the mPFC and PCC compared with pre-manipulation. Mindfulness-meditation-related decreases in pain intensity ratings were associated with greater activation in the
bilateral OFC, subgenual ACC, right anterior insula, and putamen. Greater deactivation of the left inferior parietal lobe was associated with greater pain intensity reductions. Meditation-induced
reductions in pain unpleasantness ratings were associated with greater activation in the left inferior frontal gyrus and frontal operculum. B, Bottom left, Placebo (placebo ( heat) reduced
pain-related activation in the bilateral frontal operculum, SII, posterior insula, and right inferior frontal gyrus. Placebo activated the ACC and DLPFC. Placebo-induced pain intensity reductions were
associated with greater deactivation in the contralateral SII/parietal operculum. C, Bottom right, Sham mindfulness meditation (sham meditation ( heat) produced deactivation of the ACC.
Compared with pre-manipulation, there was greater sham mindfulness-meditation-related activation in the thalamus, SMA, right SI, and putamen.
Table 4. Multiple regression analysis assessing the relationship among pain
unpleasantness ratings, respiration rate, and group in MRI session B (n " 75)
Variable B SE B
$
sr
2
Model R
2
F
0.64 30.41*
Pre-pain unpleasantness 0.71 0.08 0.63* 0.40
Pre-pain respiration rate '0.02 0.06 '0.03 0.0009
Post-pain respiration rate 0.16 0.05 0.33** 0.06
Group '0.37 0.18 '0.20*** 0.02
B, unstandardized beta coefficient; SE B, standard error of unstandardized beta coefficient;
$
, standardized beta
coefficient; sr
2
, semi-partial coefficientsquared; pre-painunpleasantness, pre-manipulation-related pain unpleas
-
antness ratings; pre-pain respiration rate, pre-manipulation respiration rate; post-pain respiration rate, post-
manipulation respiration rate. *p ! 0.001. **p " 0.001. ***p " 0.04.
Table 5. Multiple regression analysis depicting the relationship between lower
respiration rate and lower pain unpleasantness ratings for the sham-mindfulness
meditation group (n " 20) in MRI session B
Variable B SE B
$
sr
2
Model R
2
F
0.44 4.25*
Pre-pain unpleasantness 0.50 16 0.60** 0.32
Pre-pain respiration rate '0.03 0.09 '0.07 0.004
Post-pain respiration rate 0.14 0.06 0.45*** 0.18
B, unstandardized beta coefficient; SE B, standard error of unstandardized beta coefficient;
$
, standardized beta
coefficient; sr
2
, semi-partial coefficientsquared; pre-painunpleasantness, pre-manipulation-related pain unpleas
-
antness ratings;pre-pain respiration rate, pre-manipulation respiration rate; post-pain respirationrate, respiration
rate during sham meditation. *p " 0.02. **p " 0.007. ***p " 0.04.
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015 • 35(46):15307–15325 • 15321
manipulation (rest) versus post-manipulation (F
(1,66)
" 3.21,
p " 0.078), pre-manipulation versus post-manipulation $
group interaction (F
(3,66)
" 0.45, p " 0.715), differences be
-
tween “heat” and “neutral” series (F
(1,66)
" 0.28, p " 0.601),
stimulation series $ group interaction (F
(3,66)
" 0.23, p "
0.874), pre-manipulation versus post-manipulation $ stimu-
lation series interaction (F
(1,66)
" 0.11, p " 0.747), or three-
way interaction (F
(3,66)
" 0.96, p " 0.415).
Discussion
In the present study, mindfulness meditation reduced pain by
engaging brain mechanisms that were distinct from those of
placebo-induced analgesia as well as sham mindfulness med-
itation. Relative to the comparison groups, mindfulness med-
itation significantly decreased neural activation in brain
regions crucially involved in the facilitation and modula-
tion of nociceptive information (e.g., thalamus, PAG). We
have also now repeatedly (Zeidan et al., 2011)foundthat
mindfulness-meditation-based pain relief is not significantly
associated with reductions in respiration rate, providing sup-
plemental confirmation that mindfulness meditation is mech-
anistically distinct from the so-called “relaxation response”
(Beary and Benson, 1974). In conjunction with previous find-
ings (Gard et al., 2012; Grant et al., 2011; Zeidan et al., 2011;
Lutz et al., 2013), the present data demonstrate that
mindfulness-meditation-related pain relief is associated with
greater brain activation in sensory processing regions (insula,
SII) and unique cognitive reappraisal processes. However, this
study is the first to demonstrate that mindfulness meditation
is mechanistically distinct and produces reductions in pain
intensity and pain unpleasantness ratings above and beyond
the analgesic effects seen with either placebo conditioning or
sham mindfulness meditation.
Mindfulness meditation uses distinct neural mechanisms from
placebo conditioning
Consistent with the findings from our previous study (Zeidan et al.,
2011), mindfulness-based pain relief engaged brain mechanisms
involved in mediating the cognitive modulation of pain, including
the anterior insula, sgACC, and OFC. The positive relationship be-
tween mindfulness-meditation-related pain relief and increased ac-
tivation of the right anterior insula likely was associated with fine-
tuning sensory evaluations in a context-dependent manner (Oshiro
et al., 2009), whereas enhanced activations in the sgACC presumably
mediated executive-level shifts between endogenously (i.e., breath)
and exogenously driven (i.e., pain) attention (Davis et al., 1997).
Importantly, the relationship between meditation-related pain relief
and OFC activation likely reflects employment of unique reappraisal
processes involved in altering the contextual evaluation of nocicep-
tive sensory events (O’Doherty et al., 2001; Rolls and Grabenhorst,
2008).
The 4 d placebo conditioning intervention was very effec-
tive at reducing pain in MRI Session B, as reflected by an 11%
reduction in pain intensity and a 13% reduction in pain un-
pleasantness ratings from the pre-manipulation baseline. In
contrast, the control group reported a 16% increase in pain
intensity and an 18% increase in pain unpleasantness ratings
from baseline (Fig. 3). Although this is the first study to use
arterial spin labeling MRI to image the brain regions involved
in placebo analgesia, the present findings are consistent with
previous work using BOLD fMRI (Petrovic et al., 2002 ; Wager
et al., 2004; Koyama et al., 2005; Eippert et al., 2009)indem-
onstrating placebo-induced activation of the ACC and DLPFC
and deactivation in the bilateral posterior insula and SII, brain
regions involved in nociceptive processing (Coghill et al.,
1994). Placebo cream-induced analgesia was correlated with
reductions in pain-related activity in the contralateral SII. Al-
though the main effect of mindfulness meditation was associ-
ated with significant deactivation of regions of the default
mode network (PCC, mPFC) and the ACC, the main effect of
placebo did not reduce activation in these regions. These re-
sults provide further evidence that mindfulness meditation is
an active, cognitively engaging practice, whereas placebo re-
flects a more passive cognitive state, particularly in the absence
of noxious stimulation.
Mindfulness and sham mindfulness meditation reduce pain
through different mechanisms
To better understand the neural mechanisms associated with
mindfulness meditation, the active components associated with
mindfulness-based analgesia must be distinguished from those
associated with the belief that one is practicing mindfulness med-
itation (MacCoon et al., 2012), alterations in breathing rate,
bodily posture, and other potentially nonspecific factors (Zeidan
et al., 2012; Tang et al., 2015). Therefore, a sham mindfulness
meditation regimen was used to better characterize the specific
analgesic mechanisms associated with mindfulness-based medi-
tation. Importantly, whereas only the mindfulness meditation
group significantly increased in mindfulness scores ((16%; Fig.
4), there were no significant differences (p & 0.88) in “perceived
meditative effectiveness” between the mindfulness and sham
mindfulness meditation groups across their respective interven-
tions (Table 2). These data demonstrate that the sham mindful-
ness meditation intervention was effective at leading participants
to believe that they were practicing mindfulness meditation, but
only the genuine mindfulness meditation intervention resulted
in increases in mindfulness levels.
In the present study, sham mindfulness meditation produced
significant reductions in pain ratings and engaged a neural net-
work that partially overlapped with that exhibited by mindfulness
meditation. Nevertheless, differences between these two cogni-
tive practices were apparent during painful stimulation. First,
mindfulness-based meditation produced significantly greater re-
ductions in pain intensity ('27%) and pain unpleasantness
('44%) ratings than did sham mindfulness meditation (pain
intensity reduction " 8%; pain unpleasantness reduction "
27%). Second, in the presence of noxious heat stimulation, sham
mindfulness meditation produced greater activation in the thal-
amus, left putamen, SMA, PCC, and SI and greater deactivation
of the ACC and mPFC when compared to rest. However, these
analyses detected no significant relationship between interindi-
vidual changes in pain intensity/unpleasantness ratings and sham
mindfulness meditation-related brain activation (Fig. 7). Similar
to other breathing-related cognitive manipulations (Chalaye et
al., 2009; Grant and Rainville, 2009;
Martin et al., 2012), sham
mindfulness meditation-induced analgesia was positively corre-
lated with lower respiration rates (Table 5), which is consistent
with mechanisms involved facilitating relaxation responses
(Beary and Benson, 1974). In contrast, mindfulness-meditation-
reduced pain ratings were independent of respiration rate and
achieved via neural mechanisms involved in the top-down regu-
lation of pain (OFC; anterior insula; pgACC; Rainville, 2002).
Considerations for mindfulness-based pain relief
The purpose of this experiment was to determine whether
mindfulness-meditation-induced analgesia engages distinct be-
havioral and neural mechanisms from those produced by placebo
15322 • J. Neurosci., November 18, 2015 • 35(46):15307–15325 Zeidan et al. • Mindfulness Meditation-Based Pain Relief
analgesia. However, given that the present study examined
healthy, pain-free volunteers, we cannot explicitly generalize our
findings to chronic pain patients. Nevertheless, significant time
commitments have been described as a barrier to the clinical
utilization of meditation (Wearn and Greenfield, 1998). We have
repeatedly shown that as little as three 20 min daily sessions of
mindfulness-based mental training can significantly reduce pain
ratings and improve health measures (Zeidan et al., 2010b,c;
Zeidan et al., 2014). The current data build upon these findings to
reveal that mindfulness meditation produces significantly greater
pain relief than do placebo-induced interventions and presum-
ably results in enhanced pain relief because of the different neural
mechanisms that are engaged. Consistent with the engagement of
different neural mechanisms between mindfulness meditation
and placebo, mindfulness meditation also produces differen-
tial effects on psychophysical ratings of pain. That is, mindful-
ness meditation produces greater reductions in pain
unpleasantness relative to pain intensity (percent difference
between pain intensity and unpleasantness "'27%) than
placebo (percent difference between pain intensity and un-
pleasantness "(3%). It is also important to note that pain
relief produced from the cognitive state of meditation does not
likely produce lasting changes in the subjective experience of
pain.
This study could not be designed in a double-blind fashion
due to the nature of meditation training and placebo condition-
ing. Specifically, placebo cream could not be applied to all groups
because this manipulation could potentially elicit analgesia even
though the subjects were informed that the cream was inert
(Kaptchuk et al., 2010). Furthermore, whereas subjects in the
placebo-induced analgesia and book-listening control groups
were clearly aware of their group assignment, subjects in the
mindfulness and sham-mindfulness groups were blinded to
their intervention assignment. For the mindfulness and sham-
mindfulness groups, responses related to psychosocial influences
(i.e., demand characteristics) presumably were minimal given
that no significant differences in “perceived meditative effective-
ness” were observed (p " 0.88; Table 2).
The present findings demonstrate that mindfulness medita-
tion is superior in producing pain relief compared with other
cognitive training regimens in which non-judgmental reappraisal
is not an integral part of the mental training (the sham mindful-
ness meditation % relaxation response). We postulate that a
broader appreciation of these differences is an integral step in
fostering the validity of mindfulness meditation as an adjunct
therapy for mitigating pain and resultant suffering.
References
Abbott DF, Opdam HI, Briellmann RS, Jackson GD (2005) Brief breath
holding may confound functional magnetic resonance imaging studies.
Hum Brain Mapp 24:284 –290. CrossRef Medline
Andersson J, Jenkinson M, Smith SM (2007a) Non-linear optimisation.
FMRIB Technical Report TR07JA1. Available at http://www.fmrib.ox.ac.
uk/analysis/techrep/#TR07JA2.
Andersson J, Jenkinson M, Smith SM (2007b) Non-linear registration, aka
spatial normalisation. FMRIB Technical Report TR07JA2. Available at
http://www.fmrib.ox.ac.uk/analysis/techrep/#TR07JA2.
Atlas LY, Whittington RA, Lindquist MA, Wielgosz J, Sonty N, Wager TD
(2012) Dissociable influences of opiates and expectations on pain. J Neu-
rosci 32:8053– 8064. CrossRef Medline
Beary JF, Benson H (1974) A simple psychophysiologic technique which
elicits the hypometabolic changes of the relaxation response. Psychosom
Med 36:115–120. CrossRef Medline
Behzadi Y, Restom K, Liau J, Liu TT (2007) A component based noise cor-
rection method (CompCor) for BOLD and perfusion based fMRI. Neu-
roimage 37:90 –101. CrossRef Medline
Benedetti F, Mayberg HS, Wager TD, Stohler CS, Zubieta JK (2005) Neuro-
biological mechanisms of the placebo effect. J Neurosci 25:10390 –10402.
CrossRef Medline
Bingel U, Lorenz J, Schoell E, Weiller C, Bu¨chel C (2006) Mechanisms of
placebo analgesia: rACC recruitment of a subcortical antinociceptive net-
work. Pain 120:8–15. CrossRef Medline
Birn RM, Murphy K, Handwerker DA, Bandettini PA (2009) fMRI in the
presence of task-correlated breathing variations. Neuroimage 47:1092–
1104. CrossRef Medline
Brown CA, Jones AK (2010) Meditation experience predicts less negative
appraisal of pain: electrophysiological evidence for the involvement of
anticipatory neural responses. Pain 150:428– 438. CrossRef Medline
Buxton RB, Wong EC, Frank LR (1998) Dynamics of blood flow and oxy-
genation changes during brain activation: the balloon model. Magn
Reson Med 39:855–864. CrossRef Medline
Chalaye P, Goffaux P, Lafrenaye S, Marchand S (2009) Respiratory effects
on experimental heat pain and cardiac activity. Pain Med 10:1334–1340.
CrossRef Medline
Coghill RC, Eisenach J (2003) Individual differences in pain sensitivity: im-
plications for treatment decisions. Anesthesiology 98:1312–1314.
CrossRef Medline
Coghill RC, Talbot JD, Evans AC, Meyer E, Gjedde A, Bushnell MC, Duncan
GH (1994) Distributed processing of pain and vibration by the human
brain. J Neurosci 14:4095– 4108. Medline
Coghill RC, Sang CN, Berman KF, Bennett GJ, Iadarola MJ (1998) Global
cerebral blood flow decreases during pain. J Cereb Blood Flow Metab
18:141–147. Medline
Coghill RC, Sang CN, Maisog JM, Iadarola MJ (1999) Pain intensity pro-
cessing within the human brain: a bilateral, distributed mechanism.
J Neurophysiol 82:1934–1943. Medline
Coghill RC, McHaffie JG, Yen YF (2003) Neural correlates of interindi-
vidual differences in the subjective experience of pain. Proc Natl Acad Sci
U S A 100:8538– 8542. CrossRef Medline
Cohen BH, Lea RB (2004) Essentials of statistics for the social and behav-
ioral sciences. Hoboken, NJ: Wiley.
Colloca L, Petrovic P, Wager TD, Ingvar M, Benedetti F (2010) How the
number of learning trials affects placebo and nocebo responses. Pain 151:
430–439. CrossRef Medline
Cropley M, Ussher M, Charitou E (2007) Acute effects of a guided relax-
ation routine (body scan) on tobacco withdrawal symptoms and cravings
in abstinent smokers. Addiction 102:989–993. CrossRef Medline
Davis KD, Taylor SJ, Crawley AP, Wood ML, Mikulis DJ (1997) Functional
MRI of pain- and attention-related activations in the human cingulate
cortex. J Neurophysiol 77:3370 –3380. Medline
Eippert F, Bingel U, Schoell ED, Yacubian J, Klinger R, Lorenz J, Bu¨chel C
(2009) Activation of the opioidergic descending pain control system un-
derlies placebo analgesia. Neuron 63:533–543. CrossRef Medline
Fox MD, Snyder AZ, Vincent JL, Corbetta M, Van Essen DC, Raichle ME
(2005) The human brain is intrinsically organized into dynamic, anticor-
related functional networks. Proc Natl Acad Sci U S A 102:9673–9678.
CrossRef Medline
Gard T, Ho¨lzel BK, Sack AT, Hempel H, Lazar SW, Vaitl D, Ott U (2012)
Pain attenuation through mindfulness is associated with decreased cog-
nitive control and increased sensory processing in the brain. Cereb Cortex
22:2692–2702. CrossRef Medline
Garland EL, Gaylord SA, Palsson O, Faurot K, Douglas Mann J, Whitehead
WE (2012) Therapeutic mechanisms of a mindfulness-based treatment
for IBS: effects on visceral sensitivity, catastrophizing, and affective pro-
cessing of pain sensations. J Behav Med 35:591– 602. Medline
Gastl M, Bru¨nner YF, Wiesmann M, Freiherr J (2014) Depicting the inner
and outer nose: The representation of the nose and the nasal mucosa on
the human primary somatosensory cortex (SI). Hum Brain Mapp 35:
4751–4766. CrossRef Medline
Geuter S, Eippert F, Hindi Attar C, Bu¨chel C (2013) Cortical and subcortical
responses to high and low effective placebo treatments. Neuroimage 67:
227–236. CrossRef Medline
Grant JA, Rainville P (2009) Pain sensitivity and analgesic effects of mindful
states in Zen meditators: a cross-sectional study. Psychosomatic Medicine
71:106–114. CrossRef Medline
Grant JA, Courtemanche J, Duerden EG, Duncan GH, Rainville P (2010)
Zeidan et al. • Mindfulness Meditation-Based Pain Relief J. Neurosci., November 18, 2015
• 35(46):15307–15325 • 15323
Cortical thickness and pain sensitivity in zen meditators. Emotion 10:
43–53. CrossRef Medline
Grant JA, Courtemanche J, Rainville P (2011) A non-elaborative mental
stance and decoupling of executive and pain-related cortices predicts low
pain sensitivity in Zen meditators. Pain 152:150 –156. CrossRef Medline
Ho¨lzel BK, Lazar SW, Gard T, Schuman-Olivier Z, Vago DR, Ott U (2011)
How does mindfulness meditation work? Proposing mechanisms of ac-
tion from a conceptual and neural perspective. Perspect Psychol Sci
6:537–559. CrossRef Medline
Jenkinson M, Bannister P, Brady M, Smith S (2002) Improved optimization
for the robust and accurate linear registration and motion correction of
brain images. Neuroimage 17:825– 841. CrossRef Medline
Kabat-Zinn J (1982) An outpatient program in behavioral medicine for
chronic pain patients based on the practice of mindfulness meditation:
theoretical considerations and preliminary results. Gen Hosp Psychiatry
4:33–47. Medline
Kabat-Zinn J, Lipworth L, Burney R (1985) The clinical use of mindfulness
meditation for the self-regulation of chronic pain. J Behav Med 8:163–
190. CrossRef Medline
Kaptchuk TJ, Friedlander E, Kelley JM, Sanchez MN, Kokkotou E, Singer JP,
Kowalczykowski M, Miller FG, Kirsch I, Lembo AJ (2010) Placebos
without deception: a randomized controlled trial in irritable bowel syn-
drome. PLoS One 5:e15591. CrossRef Medline
Kastrup A, Li TQ, Glover GH, Moseley ME (1999a) Cerebral blood flow-
related signal changes during breath-holding. AJNR Am J Neuroradiol
20:1233–1238. Medline
Kastrup A, Kru¨ger G, Glover GH, Neumann-Haefelin T, Moseley ME
(1999b) Regional variability of cerebral blood oxygenation response to
hypercapnia. Neuroimage 10:675–681. CrossRef Medline
Kety SS, Schmidt CF (1948) The effects of altered arterial tensions of carbon
dioxide and oxygen on cerebral blood flow and cerebral oxygen consump-
tion of normal young men. J Clin Invest 27:484 –492. CrossRef Medline
Kirk R (1995) Experimental design: procedures for the behavioral sciences,
Ed 3. Pacific Grove, CA: Brooks/Cole.
Koyama T, McHaffie JG, Laurienti PJ, Coghill RC (2005) The subjective
experience of pain: where expectations become reality. Proc Natl Acad Sci
U S A 102:12950–12955. CrossRef Medline
Leber AB (2010) Neural predictors of within-subject fluctuations in atten-
tional control. J Neurosci 30:11458–11465. CrossRef Medline
Lobanov OV, Quevedo AS, Hadsel MS, Kraft RA, Coghill RC (2013) Fron-
toparietal mechanisms supporting attention to location and intensity of
painful stimuli. Pain 154:1758 –1768. CrossRef Medline
Lobanov OV, Zeidan F, McHaffie JG, Kraft RA, Coghill RC (2014) From cue
to meaning: brain mechanisms supporting the construction of expecta-
tions of pain. Pain 155:129–136. CrossRef Medline
Luh WM, Wong EC, Bandettini PA, Ward BD, Hyde JS (2000) Comparison
of simultaneously measured perfusion and BOLD signal increases during
brain activation with T(1)-based tissue identification. Magn Reson Med
44:137–143. Medline
Lui F, Colloca L, Duzzi