Data visualizations ↑
Abstract ↑
Longitudinal evidence about the effects of sustained zazen on nondual awareness and neural markers is limited. This single-subject study examines ongoing phenomenological and neural trajectories across an indefinite period of zazen, with initial analytical results after 8 weeks (56 days) of daily meditation. EEG data (Muse 2 headband) capture oscillatory dynamics during 30-minute meditation sessions half an hour after waking. Phenomenological assessment employs daily NADA-S (state) after meditation sessions, weekly NADA-T (trait) once a week, and daily end-of-evening carryover items. Primary outcomes include band-specific power and cross-band ratios (gamma/theta, theta/alpha, beta/alpha). Growth curve modeling with time as a continuous predictor quantifies trajectories. This design addresses whether zazen-induced shifts in nondual consciousness and neural function exhibit systematic deepening in a moderately experienced Zen meditator.
Introduction ↑
Nondual awareness (NDA)—experiential dissolution of subject-object boundaries—characterizes zazen phenomenology. Josipovic (2014) defines NDA as “background awareness that precedes conceptualization and can contextualize contents without fragmenting experience into habitual dualities.” Zazen, Zen Buddhism’s seated meditation practice, emphasizes sustained open-monitoring awareness through a stable posture (eyes half-open), non-reactive receptivity to arising phenomena (breath, sounds, thoughts), and lack of selective attentional focus. Practitioners report progressive boundary dissolution between “me meditating” and “meditation experience,” culminating in witnessing awareness prior to differentiation between the experiencer and the experienced (Austin, 2013; Cooper & Northoff, 2022).
Hanley et al. (2018) developed the Nondual Awareness Dimensional Assessment (NADA) in validating state (NADA-S) and trait (NADA-T) versions ). Factor analysis identified two dimensions: self-transcendence (boundary dissolution, expanded awareness) and bliss (peace, warmth, contentment). NADA-S captures immediate post-session phenomenology while NADA-T measures dispositional shifts across longer timeframes. Mindfulness practitioners show higher NADA-T scores than non-practitioners, with practice frequency positively correlating with nondual awareness levels.
Neural correlates of NDA include elevated delta, theta, alpha during nondual events versus general meditation (Berman & Stevens, 2015), and reduced anti-correlation between task-positive and default-mode network activation-during nondual states (Josipovic, 2014). Ordinarily these networks show strong negative correlations as brain activity toggles between external task engagement and internal self-reference. During NDA, this antagonism softens, suggesting a neural configuration allowing simultaneous activation, potentially reflecting awareness of inner and outer experience without dualistic fragmentation. Schoenberg et al. (2018) found gamma-band increases within the anterior cingulate cortex, precuneus, and superior parietal lobule during “awakened awareness” in advanced practitioners, suggesting self-processing reconfiguration rather than deactivation.
Zazen-specific research reports characteristic progressions. Kasamatsu and Hirai (1966) established alpha appearance within 50 seconds despite an eyes-open condition, amplitude increases peaking at 15-20 minutes, frequency decreases toward lower alpha, and theta emergence in advanced practitioners. These patterns correlated with meditation experience and resistance to alpha-blocking habituation—zazen cultivates sustained awareness without habituation, indicating non-selective receptivity (Dunn et al., 1999). LORETA source localization reveals increased right-hemisphere alpha with decreased bilateral beta in the posterior cingulate and parietal cortices (Faber et al., 2015), interpreted as internally directed attention with diminished analytical processing. Murata et al. (1994) reported increased frontal midline theta; Hauswald et al. (2015) found decreased frontal theta/beta. Pasquini et al. (2025) demonstrated advanced monks maintain meditation-like neural configurations even during mind-wandering, hinting at trait-level integration where meditative awareness pervades consciousness.
Berkovich-Ohana et al. (2015) discovered high-frequency gamma correlations (100-245 Hz) with trait mindfulness, localized to somatosensory cortices, the anterior cingulate cortex, and the parahippocampus. This extends Lutz et al.’s (2004) seminal finding that long-term practitioners self-induce gamma synchrony. Critically, Lutz et al. demonstrated gamma/theta and gamma/alpha ratios provide more sensitive markers than absolute power, a methodological insight that informs subsequent meditation neuroscience (Cahn & Polich, 2006; Tang et al., 2015).
Critical methodological gaps persist. Most zazen studies employ group comparisons obscuring individual trajectories, and virtually none systematically track phenomenological and neural evolution across extended daily practice in single individuals. State-dependent versus trait-level consolidation remains underexplored in single-subject contexts enabling dense repeated measurement.
The current study is ongoing and indefinite. The longitudinal design addresses the above gaps through concurrent EEG and phenomenological assessment. Initial analysis occurs after 56 days, a duration which aligns with established mindfulness-based stress reduction (MBSR) protocol and evidence documenting neural plasticity within this timeframe—Hölzel et al. (2011) demonstrated gray matter density increases in hippocampus, posterior cingulate cortex, temporoparietal junction following 8-week MBSR; Tang et al. (2020) found posterior cingulate volume increases after 10 hours distributed across 2-4 weeks; multiple studies document functional connectivity reorganization within 8 weeks (Farb et al., 2007; Goldin & Gross, 2010; Shao et al., 2016).
The study employs NADA-S daily and NADA-T weekly to distinguish immediate post-session states from evolving trait dispositions, supplemented by end-of-evening carryover assessment (7:00-9:30 PM, ~12.5-15 hours post-session) measuring whether nondual awareness extends into daily consciousness. Neural assessment focuses on cross-band ratios (gamma/theta, theta/alpha, beta/alpha) as sensitive markers. Growth curve modeling treats time continuously (Day 1-56), allowing data-driven identification of linear, non-linear, or transitional patterns without arbitrary phase divisions.
Methods ↑
Participant. Male, age 48 at inception of study, moderately experienced Zen meditator with five 7-day residential retreats and two 3-month intensive practice periods (ango) over 15 years of intermittent practice. No diagnosed psychiatric or neurological conditions, current psychotropic medications, or seizure history.
Design. Ongoing, indefinite single-subject longitudinal study. Initial analysis at 8 weeks (56 consecutive days) of daily zazen at consistent timepoint (30 minutes after waking) to control circadian effects on EEG patterns and phenomenological states.
Zazen Protocol. Daily 30-minute sessions following traditional Soto Zen protocol. Stable posture (quarter lotus, alternating legs each day) with eyes half-open, soft downward gaze toward floor approximately three feet ahead. Practice emphasizes choiceless open-monitoring awareness: sustained receptive attention to totality of arising experience (breath sensations, sounds, thoughts, emotions, bodily feelings) without selective focus on particular objects. Thoughts and sensations arise and pass within awareness field without suppression, elaboration, identification, or engagement—embodying “just sitting” (shikantaza) characterized by effortless allowing rather than goal-oriented striving.
EEG Acquisition. Muse 2 headband (InteraXon Inc.) provides 4-channel EEG (TP9, AF7, AF8, TP10 electrodes: left/right temporal and frontal regions), 256 Hz sampling, Bluetooth transmission to MuseLab 3.0 (macOS). Pre-session fitting ensures horseshoe signal quality indicators ≤2 (green/yellow=adequate contact); epochs HSI >2 (poor quality) excluded post-hoc. Continuous 30-minute recording. Immediate post-session export yields CSV files containing raw voltage, artifact-corrected band power estimates (delta, theta, alpha, beta, gamma), and per-electrode quality indicators.
Band-specific absolute power (μV²) calculated via Fast Fourier Transform: delta 0.5-4 Hz, theta 4-8 Hz, alpha 8-12 Hz, beta 13-30 Hz, gamma 30-100 Hz. Power values averaged across four electrodes yielding single value per band per session, reducing spatial variability while retaining temporal dynamics. Cross-band ratios computed following Lutz et al. (2004): (1) gamma/theta (primary marker given demonstrated sensitivity), (2) theta/alpha (meditative absorption index), (3) beta/alpha (analytical processing index). Ratios provide internal normalization reducing individual baseline variability and potentially offering more stable markers than absolute power across extended observation.
Phenomenological Assessment. NADA-S administered daily within 5 minutes post-session via smartphone Google Forms: 10 items, 1-10 scale (“not at all” to “completely”), assessing self-transcendence (5 items: boundary dissolution, mind-world undivided, openness, mind expanding, release from thought-identification) and bliss (5 items: blissful, boundless, warm energy, peace, stillness) during just-completed session (Appendix A). Subscale scores = mean of constituent items; total score = mean across all items.
NADA-T administered weekly (Sundays) via Google Forms: 10 parallel items, 1-6 scale (“almost never” to “almost always”), assessing dispositional nondual awareness “over past week” following Hanley et al.’s (2018) original validation protocol (Appendix A). Weekly rather than daily administration reduces measurement reactivity (conscious tracking of trait changes) and recall bias (distinguishing current from recent days).
End-of-evening carryover administered daily 7:00-9:30 PM (~12.5-15 hours post-session) via Google Forms: (1) “Throughout today, how present and aware were you during routine activities?” (0-10), (2) “How non-reactive were you to challenging situations or emotions today?” (0-10), (3) “Did nondual awareness (boundaries dissolving, expanded consciousness) extend into daily life today?” (0-10). Item 3 serves as primary carryover marker; items 1-2 capture related mindfulness dimensions. 7:00-9:30 PM window targets evening after daily activities conclude but before sleep routines begin.
Weekly qualitative reflection (Sundays, following NADA-T): open-ended prompt “Reflect on past week: What patterns, insights, or changes noticed in sessions and daily life? (1-3 sentences).” Archived for thematic analysis of phenomenological shifts, practice challenges, critical transitions, daily-life integration not captured quantitatively.
Hypotheses ↑
H1: Nondual awareness state and trait measures increase across 8 weeks. Both NADA-S (daily state) and NADA-T (weekly trait) total scores will exhibit positive growth trajectories. Self-transcendence subscale expected to show greater magnitude of change than bliss subscale, consistent with zazen’s phenomenological emphasis on boundary dissolution over affective qualities. Hypothesis grounded in cross-sectional evidence that practice frequency correlates with NADA levels (Hanley et al., 2018) and longitudinal findings of dispositional shifts following sustained meditation (Hölzel et al., 2011).
H2: Gamma/theta ratio increases across 8 weeks. Following Lutz et al.’s (2004) identification of gamma/theta ratios as sensitive meditation markers through internal normalization, this primary neural outcome hypothesized to increase systematically across 56 days. Predicted pattern reflects heightened awareness (gamma) integrated with deepening meditative absorption (theta), consistent with zazen’s cultivation of alert receptivity.
H3: End-of-evening nondual carryover increases across 8 weeks. Progressive increases in Item 3 (“Did nondual awareness extend into daily life today?”) would indicate trait-level integration where nondual awareness becomes accessible outside formal sessions. Provides converging evidence with NADA-T for dispositional shifts, testing whether repeated exposure to nondual states during practice transfers to spontaneous accessibility in daily consciousness (cf. Pasquini et al., 2025 findings of meditation-like configurations during mind-wandering in advanced monks).
H4: NADA-S and NADA-T correlations strengthen over time. As practice deepens, state and trait measures should exhibit increasing alignment—that is, immediate post-session experiences become more predictive of general dispositional nondual awareness. Hypothesis reflects state-trait consolidation where acute phenomenological shifts crystallize into stable dispositional patterns, operationalized through initial comparison of correlations on a weekly basis.
H5: Phenomenological and neural markers correlate positively. Daily NADA-S total scores hypothesized to correlate with same-session gamma/theta ratios (r > 0.3), providing construct validity evidence that neural markers track subjective nondual awareness experiences rather than non-specific arousal or attentional states. Threshold r > 0.3 represents medium effect size in correlational research, indicating meaningful covariation between phenomenology and neural dynamics.
Statistical analysis ↑
Growth curve modeling employs R nlme package with time (day number) as continuous Level 1 predictor. Unconditional models test both linear (β₁*Day) and quadratic (β₁*Day + β₂*Day²) specifications for each outcome variable. AIC and BIC model comparison identifies best-fitting trajectory shape without a priori phase divisions. Quadratic superiority would indicate non-linear patterns (e.g., rapid initial increase followed by plateau); linear superiority would suggest monotonic change. Random intercepts accommodate between-day variability; random slopes tested if data support sufficient variance estimation.
Effect sizes calculated as Cohen’s d for empirically-identified change periods. If growth curve models reveal inflection points (e.g., acceleration shift at Day 30), d calculated comparing means before versus after inflection. Otherwise, d compares week-on-week. Interpretation follows conventional benchmarks: d = 0.2 small, d = 0.5 medium, d = 0.8 large. Given single-subject design precluding traditional inference, effect sizes provide primary interpretive framework rather than p-values. Permutation testing (1000 iterations, randomly shuffling time labels) assesses whether observed trajectories exceed chance.
Pearson correlations examine phenomenology-neural relationships across 56 daily observations (NADA-S, gamma/theta ratios). For H4 (state-trait correlation strengthening), separate correlations computed for weeks 1-4 (early) versus 5-8 (late); Fisher r-to-z transformation tests whether coefficients differ significantly (z = (z₁-z₂)/√(1/(n₁-3) + 1/(n₂-3))). Time-lagged cross-correlations test temporal precedence by correlating NADA-S(Day t) with gamma/theta(Day t-1) and vice versa, informing causal ordering (neural changes preceding phenomenological or reverse).
Autocorrelation functions (ACF) assess serial dependencies via lag-k autocorrelations ρₖ = Cor(Yₜ, Yₜ₋ₖ). Significant autocorrelation (|ρₖ| exceeding 2/√n confidence bounds) indicates non-independence requiring autoregressive error structure in growth models to prevent standard error underestimation. Change-point detection employs Pruned Exact Linear Time (PELT) algorithm testing for discrete trajectory shifts. While not hypothesized a priori, identified transitions would suggest distinct practice phases meriting post-hoc interpretation.
Alpha = 0.05 for all tests, though interpretation emphasizes effect sizes, confidence intervals, trajectory patterns over dichotomous significance. Missing data handled via maximum likelihood estimation assuming missing-at-random. Sensitivity analyses exclude days with poor EEG quality (>50% epochs HSI >2) or missing survey responses, assessing result stability.
Data descriptions ↑
Neural Oscillations (EEG)
delta_db, theta_db, alpha_db, beta_db, gamma_db — Band-specific power spectral density (PSD) in decibels. Values represent summed PSD across frequencies within each band (delta: 0.5-4 Hz, theta: 4-8 Hz, alpha: 8-12 Hz, beta: 13-30 Hz, gamma: 30-100 Hz), averaged across four electrodes (TP9, AF7, AF8, TP10), then log-transformed via 10·log₁₀. Higher values indicate greater neural oscillatory activity in that frequency range.
gamma_theta_ratio — Primary neural marker for meditation depth. Ratio of gamma-band to theta-band absolute power (μV²). Following Lutz et al. (2004), internal normalization reduces individual baseline variability. Elevated ratios suggest heightened awareness (gamma) integrated with meditative absorption (theta).
theta_alpha_ratio — Meditative absorption index. Ratio of theta to alpha absolute power. Lower values may indicate alpha dominance characteristic of relaxed wakefulness; higher values suggest theta-dominant states associated with deep meditation.
beta_alpha_ratio — Analytical processing index. Ratio of beta to alpha absolute power. Higher values indicate increased cognitive engagement or analytical activity; lower values suggest reduced conceptual processing.
Phenomenological Assessments
self_transcendence (NADA-S, daily) — Mean score across 5 items (1-10 scale) assessing boundary dissolution phenomenology: boundaries dissolving, mind-world undivided, openness to experience, mind expanding into space, release from thought-identification. Higher scores indicate greater experiential nonduality during session.
bliss (NADA-S, daily) — Mean score across 5 items (1-10 scale) assessing affective qualities: blissfulness, boundless freedom, warm energy, peace, inner stillness. Higher scores indicate greater positive affect accompanying nondual states.
nada_s_total (daily) — Overall nondual awareness state score, computed as mean of self-transcendence and bliss subscales. Administered within 5 minutes post-session, captures immediate phenomenological characteristics.
trait_self_transcendence, trait_bliss, nada_t_total (weekly) — Parallel trait measures (1-6 scale) assessing dispositional nondual awareness “over past week.” Administered Sundays. Progressive increases would indicate consolidation from state-dependent to trait-level characteristics.
nondual_carryover (daily, evening) — Single item (0-10 scale): “Did nondual awareness (boundaries dissolving, expanded consciousness) extend into daily life today?” Assessed 7:00-9:30 PM (~12.5-15 hours post-session). Rising scores indicate trait integration where nondual awareness becomes accessible outside formal practice.
presence, non_reactivity (daily, evening) — Supplementary mindfulness dimensions: present awareness during routine activities, non-reactivity to challenges (both 0-10 scale). Provide context for nondual carryover without direct nonduality assessment.
Data Quality Indicators
max_hsi — Worst (maximum) Horseshoe Signal Indicator value across all electrodes during session. Scale: 1=green (excellent), 2=yellow (adequate), 3=orange (poor), 4=red (very poor/none). Values >2 flag sessions with signal quality degradation.
poor_signal_pct — Percentage of epochs with HSI >2 for any electrode. Sessions with >50% poor signal percentage automatically flagged for sensitivity analyses.
excessive_motion — Binary flag (TRUE/FALSE) indicating accelerometer standard deviation exceeded 0.1g threshold, suggesting movement artifact contamination.
quality_flag — Overall session quality flag combining poor_signal_pct and excessive_motion criteria. Flagged sessions retained in dataset but excluded in sensitivity analyses assessing result stability.
Temporal Variables
date — Session date (YYYY-MM-DD format). Extracted from EEG filename.
day — Sequential day number (1-56). Primary temporal predictor in growth curve models.
Hardware ↑
The data above was collected using the Muse 2 headset and the Mind Monitor app. The headset has five dry electrodes located at locations TP9, TP10, AF7, AF8, and FpZ, which refer to the international 10-20 system. Letters correspond to the pre-frontal (Fp), frontal (F), temporal (T), parietal (P), occipital (O), and central (C) brain regions. Numbers correspond to hemisphere: the left hemisphere of the brain is given even numbers, the right hemisphere odd numbers, and the midline sagittal plane of the skull—the line connecting just above the nose (“nasion”) to the back of the skull (“inion”)—is labeled “z” for zero.
Figure 1 shows the location of the Muse 2 electrodes; note that Fpz serves as the reference electrode, placed in a neutral location with respect to hemispheric activity. The other electrodes measure the differences in electrical potential between FpZ and their locations. The Muse 2 electrodes are focused on activity in the temporal, parietal, and frontal lobes.
Note that the Muse 2 headband, while effective for general EEG data, lacks the clinical-grade precision of laboratory-grade equipment, potentially influencing the sensitivity of oscillatory measurements.
Expected Outcomes ↑
Supported hypotheses would provide dense longitudinal single-subject evidence that zazen systematically deepens nondual awareness and reconfigures neural dynamics in a moderately experienced Zen meditator. Progressive NADA-S and NADA-T increases would demonstrate both immediate post-session states and dispositional awareness strengthen, with self-transcendence exceeding bliss changes. Gamma/theta ratio increases would validate this primary neural marker tracking phenomenological deepening (effect sizes potentially d > 0.5). Rising end-of-evening carryover converging with NADA-T increases would indicate trait consolidation extending beyond formal practice. Strengthening NADA-S/NADA-T correlations would suggest state-trait alignment. Positive phenomenology-neural correlations would provide construct validity that EEG markers track nondual awareness rather than general arousal.
Growth curve modeling may reveal non-linear trajectories (initial increases then plateaus) or critical transitions via change-point detection, informing understanding of meditation-induced change processes. Linear trajectories would indicate monotonic deepening without phase boundaries.
Null or weak findings after 8 weeks (or longer) would suggest: (1) 8 weeks insufficient for detecting changes in experienced practitioners, (2) consumer-grade EEG lacks sensitivity for zazen-specific changes, (3) daily NADA-S introduces measurement reactivity, (4) weekly NADA-T lacks temporal resolution for evolving trait shifts, or (5) individual variability exceeds general patterns, limiting single-subject generalizability. These carry implications for optimal assessment frequency and instrumentation sensitivity in experienced meditator research.
Further reading ↑
☆ Kasamatsu, A. & Hirai, T. (1966). An electroencephalographic study on the Zen meditation (zazen). Psychiatry and Clinical Neurosciences 20, 315–336. An extraordinary early study of the neural correlates of Zen meditation. Analyzing a sample of 48 Zen practitioners of varying experience and a control group of 22 volunteers—a large sample even by today’s standards of meditation research—the authors find that zazen is characterized by four stages: 1) the appearance of alpha waves, 2) an increase in alpha wave amplitude, 3) a decrease in alpha wave frequency, and 4) the arrival of a theta train. Experienced meditators were also more likely() to resist habituation to a click stimulus. These patterns were positively correlated with meditation experience. 10
☆Lutz, A., Greischar, L. L., Rawlings, N. B., Ricard, M., & Davidson, R. J. (2004). Long-term meditators self-induce high-amplitude gamma synchrony during mental practice. Proceedings of the National Academy of Sciences, 101(46), 16369-16373. A very influential study showing that gamma oscillations, both absolute and as a ratio with slow waves (theta and alpha), may be the strongest signals of non-directed meditative states, such as those produced by loving-kindness meditation (and potentially zazen). 10
☆ Brewer, J. A., Worhunsky, P. D., Gray, J. R., Tang, Y. Y., Weber, J., & Kober, H. (2011). Meditation experience is associated with differences in default mode network activity and connectivity. Proceedings of the National Academy of Sciences, 108(50), 20254-20259. The first study to establish that key nodes of the default mode network (DMN), especially the posterior cingulate cortex and the medial prefrontal cortex, are relatively deactivated in meditators. Functional connectivity across brain regions was also enhanced among meditators. 9
☆ Tang, Y. Y., Hölzel, B. K., & Posner, M. I. (2015). The neuroscience of mindfulness meditation. Nature Reviews Neuroscience, 16(4), 213-225. An excellent overview of the field circa 2015. Tang et al. provide conceptual and physical maps of the relationship between brain functioning and meditation. The reference list serves as a comprehensive index. 9
Cahn, B. R., Delorme, A., & Polich, J. (2010). Occipital gamma activation during Vipassana meditation. Cognitive Processing, 11, 39-56. Careful work: a focus on a specific type of meditation, Vipassana; a nuanced description of results with respect to brain region; an exploration of confounders. The strongest results are a decrease in frontal delta and an increase in parieto-occiptal gamma power, with few state effects for the theta, beta, and alpha bands. The authors suggest the applicability of early alpha findings may be limited to novice meditators. 8
Aftanas, L. I., & Golocheikine, S. A. (2001). Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: high-resolution EEG investigation of meditation. Neuroscience letters, 310(1), 57-60. A theta-focused study of Sahaja Yoga meditation. Key conclusions include much greater theta and alpha-1 power in long-term versus short-term meditators, especially in anterior temporal and frontal regions; increased theta synchronization between (especially left) prefrontal region (AF3) and posterior association cortex; and more intense bliss feelings, and reduced thought appearance, correlated with increased theta power in anterior frontal and frontal midline areas and increased alpha-1 power in midcentral areas. Theta phenomena are possibly linked to focused attention, enhanced positive emotion, and reduced anxiety. 7
Banquet, J. P. (1973). Spectral analysis of the EEG in meditation. Electroencephalography and Clinical Neurophysiology, 35(2), 143-151. Another confirmation of Kasamatsu (alpha dominance, lowering in frequency and increasing in amplitude, followed by theta trains) with some additional observations on rhythmic beta waves among advanced meditators. 7
Buzsaki, G., & Draguhn, A. (2004). Neuronal oscillations in cortical networks. Science, 304(5679), 1926-1929. A useful summary of electrical activity patterns in the mammalian brain, with presentation of possible functions of synchronized firing with given frequency bands. 7
Cahn, B. R., & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological bulletin, 132(2), 180. A well-organized review of the effects of meditation on the brain. Theta and alpha power increase in amplitude, and alpha decreases in frequency, as one becomes more experienced in practice. Both trait (during practice) and state (long-term) impacts are present. More work is needed on distinguishing traditions, experience, and early-stage sleep markers. 7
Cahn, B. R., Delorme, A., & Polich, J. (2013). Event-related delta, theta, alpha and gamma correlates to auditory oddball processing during Vipassana meditation. Social cognitive and Affective Neuroscience, 8(1), 100-111. More sensitivity and awareness to stimuli, and decreased automatic reactivity, reflected in theta-phase consistency, early-event alpha synchronization, decreased early-evoked delta, and late-event alpha desynchronization. 7
Fayed, N., Lopez del Hoyo, Y., Andres, E., Serrano-Blanco, A., Bellón, J., Aguilar, K., … & Garcia-Campayo, J. (2013). Brain changes in long-term zen meditators using proton magnetic resonance spectroscopy and diffusion tensor imaging: a controlled study. PLoS One, 8(3), e58476. The first study to use magnetic resonance spectroscopy to look at the effects of long-term meditation on cerebral metabolism. Meditators have higher myo-inositol in the posterior cingulate gyrus and decreased glutamate, acetyl-asparate, and N-acetyl-asparate/creatine in the left thalamus. 7
Dor-Ziderman, Y., Berkovich-Ohana, A., Glicksohn, J., & Goldstein, A. (2013). Mindfulness-induced selflessness: a MEG neurophenomenological study. Frontiers in Human Neuroscience, 7, 582. Using a framework of narrative self (NS), minimal self (MS), and selfless (SL) subjectively experienced states, Dor-Ziderman et al. find that NS attentuation (i.e., transition to MS) is associated with high-gamma decreases in power, especially in the frontal, thalamic, and extensive dorsal and central mPFC regions; and MS attentuation (i.e., transition to SL) with beta band decreases in power, especially in the left ventral mPFC and thalamus. 6
Faber, P. L., Lehmann, D., Gianotti, L. R., Milz, P., Pascual-Marqui, R. D., Held, M., & Kochi, K. (2015). Zazen meditation and no-task resting EEG compared with LORETA intracortical source localization. Cognitive Processing, 16, 87-96. Zazen-specific study that finds increased alpha-1 and alpha-2 in the right hemisphere and decreased beta-1 and beta-1 activity. The former is hypothesized to be linked to internally directed attention, wakeful resting, and emotional processing; the latter to reduced focus on the visual stream. 6
Guidotti, R., Del Gratta, C., Perrucci, M. G., Romani, G. L., & Raffone, A. (2021). Neuroplasticity within and between functional brain networks in mental training based on long-term meditation. Brain Sciences, 11(8), 1086. An fMRI/multivariate pattern analysis mapping of active (and less active) networks during focused attention and open monitoring meditation. The networks differ, and their structure predicts both age and expertise. 6
Lutz, A., Jha, A. P., Dunne, J. D., & Saron, C. D. (2015). Investigating the phenomenological matrix of mindfulness-related practices from a neurocognitive perspective. American Psychologist, 70(7), 632. Lutz et al.’s ideas are helpful not because of their plausibility—it’s not at all clear that their functional dimensions are orthogonal; it’s easy to think of arguments for dereification leading to lowered object orientation, for example, or meta-awareness facilitating dereification—but because the exercise itself helps untangle some of the conceptual mess. There’s a lot of work to be done, and proposals that generate hypotheses are a critical part of the game. 6
Omori, M., Kosaka, H., Kikuchi, M., … & Wada, Y. (2005). Changes in EEG and autonomic nervous activity during meditation and their association with personality traits. International Journal of Psychophysiology, 55(2), 199-207. Increases in fast theta and slow alpha in 20 inexperienced Zen meditators. Useful look at linkages to personality, including observed positive correlations with novelty seeking and harm avoidance. 6
Wallace, R. K. (1970). Physiological effects of transcendental meditation. Science, 167(3926), 1751-1754. Largely a confirmation of the results of Kasamatsu (1966) with a smaller and WEIRDer sample. 6
Anand, B. K., Chhina, G. S., & Singh, B. (1961). Some aspects of electroencephalographic studies in yogis. Electroencephalography and Clinical Neurophysiology, 13(3), 452-456. Cold water, strong light, loud banging, hot glass, tuning forks…nothing throws yogis off their alpha wave. An interesting early study, but the sample size (four yogis) leaves room for skepticism. 5
Davidson, R. J., & Dahl, C. J. (2018). Outstanding challenges in scientific research on mindfulness and meditation. Perspectives on Psychological Science, 13(1), 62-65. A reminder that the problems of meditation research are not new to psychology. “Mindfulness,” and even “meditation,” is not a well-defined construct. Research focuses on only a few forms of meditative practice. Many traditions indeed regard meditation as a balm for suffering, but not necessarily for the specific mental illnesses of today. Addressing individual differences and increasing sample sizes, especially through digital technology, is important. 5
Pagano, R. R., Rose, R. M., Stivers, R. M., & Warrenburg, S. (1976). Sleep during transcendental meditation. Science, 191(4224), 308-310. Sometimes you take a nap while meditating! That’s a good thing. When tired, sleep; when ready, sit. 3
Works Cited
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Berkovich-Ohana, A., Glicksohn, J., & Goldstein, A. (2015). What it means to be Zen: Marked modulations of local and interareal synchronization during open monitoring meditation. NeuroImage, 108, 265-273.
Berman, A. E., & Stevens, L. (2015). EEG manifestations of nondual experiences in meditators. Consciousness and Cognition, 31, 1-11.
Cahn, B. R., & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, 132(2), 180-211.
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Hanley, A. W., Nakamura, Y., & Garland, E. L. (2018). The Nondual Awareness Dimensional Assessment (NADA): New tools to assess nondual traits and states of consciousness occurring within and beyond the context of meditation. Psychological Assessment, 30(12), 1625-1639.
Hauswald, A., Übelacker, T., Leske, S., & Weisz, N. (2015). What it means to be Zen: Marked modulations of local and interareal synchronization during open monitoring meditation. NeuroImage, 108, 265-273.
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