Adrenocortical activity during meditation.

We studied acute plasma cortisol and testosterone concentration changes during the practice known as "transcendental meditation" (TM) and during control rest. Three groups of normal, young adult volunteers were studied: a group of controls, these same controls restudied as practitioners after 3 to 4 months of TM practice, and a group of long-term, regular TM practitioners (3 to 5 years of practice). No change was found in controls during rest. Cortisol declined, but not significantly, in restudied controls, while cortisol decreased significantly in long-term practitioners during meditation and remained somewhat low afterward. No change in testerone concentration was noted during either rest or TM. Apparently, the practice of TM becomes associated with psychophysiologic response(s) which acutely inhibit pituitary-adrenal activity.     

Physiological responses during meditation and rest

Forty nonmeditators and 12 experienced transcendental meditators were randomly assigned to four experimental cells devised to control for order and expectation effects. All 52 (female) subjects were continuously monitored on seven physiological measures during both meditation and rest. Each subject was her own control in an abab experimental paradigm comparing meditation to rest. Analyses of variance on change scores calculated from both initial and running (intertrial) baselines revealed small but significant conditions effects for all variables except diastolic BP. The same subjects (both experienced meditators and those meditating for the first time) showed lower psychophysiological arousal during the meditation than during the rest condition for systolic BP, HR, SCL, digital BV, digital ST, and frontalis EMG. The experienced meditators showed only marginally more conditions effects than the novices practicing "noncultic" meditation. For the nonmeditators, deliberately fostering positive expectations of meditations was associated with lower physiological arousal in terms of diastolic BP, HR, and SCL. These findings suggest that both cultic and noncultic meditation are associated with lower physiological activation than eyes-closed rest. The meditators, however, tended to become more relaxed over meditation trials, whereas the nonmeditators showed the opposite trend.     

The effect of transcendental meditation on iconic memory.

Three experiments investigated the effects of transcendental meditation (TM) on iconic memory. The task involved reporting of digits shown tachistoscopically, using Sperling's partial-report technique. Experiment 1 was a pilot study involving a meditation group and a nonmeditation gropu. All subjects were run in a pretest/treatment/posttest design. During the treatment phase the meditation group practiced TM for a 20-minute period and the nonmeditation group relaxed with eyes closed. The results showed that the treatment increased performance in meditators, but not in nonmeditators. In this experiment important controls such as individual administration of the task, extrinsic rewards, subject pacing, and adequate practice were lacking. Experiment 2 was a replication of the first, with these controls added. The results no longer showed a superiority for the meditation treatment. In fact, the meditation group performed worse on each day of running. Experiment 3 was a replication of Experiment 1, to assess whether the meditation effect of Experiment 1 was due to (a) differential increased attention of the meditators (minimized in subject-paced Experiment 2), (b) a gain early in learning for the meditators that was eliminated due to practice in Experiment 2, or (c) a lack of proper control procedures in Experiment 1. The performance of the meditators was, again, significantly lower. This research illustrates the importance of careful control when investigating the effects of meditation on behavior. It also suggests that the effects of meditation may depend on which hemisphere is dominant in performing the task.     

The effect of transcendental meditation on iconic memory

Three experiments investigated the effects of transcendental meditation (TM) on iconic memory. The task involved reporting of digits shown tachistoscopically, using Sperling's partial-report technique. Experiment 1 was a pilot study involving a meditation group and a nonmeditation group. All subjects were run in a pretest/treatment/posttest design. During the treatment phase the meditation group practiced TM for a 20-minute period and the nonmeditation group relaxed with eyes closed. The results showed that the treatment increased performance in meditators, but not in nonmeditators. In this experiment important controls such as individual administration of the task, extrinsic rewards, subject pacing, and adequate practice were lacking. Experiment 2 was a replication of the first, with these controls added. The results no longer showed a superiority for the meditation treatment. In fact, the meditation group performed worse on each day of running. Experiment 3 was a replication of Experiment 1, to assess whether the meditation effect of Experiment 1 was due to (a) differential increased attention of the meditators (minimized in subject-paced Experiment 2), (b) a gain early in learning for the meditators that was eliminated due to practice in Experiment 2, or (c) a lack of proper control procedures in Experiment 1. The performance of the meditators was, again, significantly lower. This research illustrates the importance of careful control when investigating the effects of meditation on behavior. It also suggests that the effects of meditation may depend on which hemisphere is dominant in performing the task.The authors wish to thank John Tabb and Cindy Miller for their assistance in conducting this research. We also wish to thank the Seattle Students International Meditation Society (SIMS) for their cooperation in obtaining subjects.     

Physiological responses during meditation and rest

Forty nonmeditators and 12 experienced transcendental meditators were randomly assigned to four experimental cells devised to control for order and expectation effects. All 52 (female) subjects were continuously monitored on seven physiological measures during both meditation and rest. Each subject was her own control in an abab experimental paradigm comparing meditation to rest. Analyses of variance on change scores calculated from both initial and running (intertrial) baselines revealed small but significant conditions effects for all variables except diastolic BP. The same subjects (both experienced meditators and those meditating for the first time) showed lower psychophysiological arousal during the meditation than during the rest condition for systolic BP, HR, SCL, digital BV, digital ST, and frontalis EMG. The experienced meditators showed only marginally more conditions effects than the novices practicing noncultic meditation. For the nonmeditators, deliberately fostering positive expectations of meditations was associated with lower physiological arousal in terms of diastolic BP, HR, and SCL. These findings suggest that both cultic and noncultic meditation are associated with lower physiological activation than eyes-closed rest. The meditators, however, tended to become more relaxed over meditation trials, whereas the nonmeditators showed the opposite trend.     

EEG Spectral Analysis on OM Mantra Meditation: A Pilot Study

Mantra meditation is easy to practice. “OM” Mantra is the highest sacred symbol in Hinduism. The present study investigated the temporal dynamics of oscillatory changes after OM mantra meditation. Twenty-three naive meditators were asked to perform loud OM chanting for 30 min and the EEG were subsequently recorded with closed eyes before and after it. To obtain new insights into the nature of the EEG after OM chanting, EEG signals were analyzed using spectral domain analysis. Statistical analysis was performed using repeated measures of analysis of variance. It did not reveal any specific band involvement into OM mantra meditation. But significantly increase in theta power was found after meditation when averaged across all brain regions. This is the main effect of OM mantra meditation. However, the theta power showed higher theta amplitude after condition at all regions in comparison to the before condition of meditation. Finding was similar to other studies documenting reduction in cortical arousal during a state of relaxation. The study argues for the potential role of loud ‘OM’ chanting in offering relaxation. It provides a new perspective of meditation to the naive meditators. This information may help to demystify meditation and encourage those considering this as beneficial practice.     

Tonic suppression of baroreceptor reflex by endogenous neurotensin in the rat

We evaluated the modulatory role of endogenous neurotensin (NT) in baroreceptor reflex (BRR) response in Sprague-Dawley rats anesthetized with pentobarbital sodium. Intracerebroventricular (i.c.v.) administration of NT (15 or 30 nmol) significantly reduced the sensitivity of the BRR response. Blocking the endogenous activity of the tridecapeptide with its specific antagonist, (D-Trp11)-NT (4 or 8 nmol) or antiserum against NT (1:20); or inhibiting the aminopeptidases with bestatin (200 nmol), on the other hand, promoted a potentiation of BRR response. When administered together with bestatin (200 nmol), the suppressive effect of NT (15 nmol) on the BRR response was further enhanced, as was the augmentative action of (D-Trp11)-NT (4 nmol). Upon microinjection into the bilateral nucleus tractus solitarius (NTS), NT (600 pmol) and (D-Trp11)-NT (150 pmol) respectively elicited a reduction and enhancement of the BRR response. These results suggest that neurons that contain NT may participate in central cardiovascular regulation by tonically suppressing the BRR, possibly via an action on the NTS where baroreceptor afferents terminate.     

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM Sleep

Over the past several years meditation practice has gained increasing attention as a non-pharmacological intervention to provide health related benefits, from promoting general wellness to alleviating the symptoms of a variety of medical conditions. However, the effects of meditation training on brain activity still need to be fully characterized. Sleep provides a unique approach to explore the meditation-related plastic changes in brain function. In this study we performed sleep high-density electroencephalographic (hdEEG) recordings in long-term meditators (LTM) of Buddhist meditation practices (approximately 8700 mean hours of life practice) and meditation naive individuals. We found that LTM had increased parietal-occipital EEG gamma power during NREM sleep. This increase was specific for the gamma range (25–40 Hz), was not related to the level of spontaneous arousal during NREM and was positively correlated with the length of lifetime daily meditation practice. Altogether, these findings indicate that meditation practice produces measurable changes in spontaneous brain activity, and suggest that EEG gamma activity during sleep represents a sensitive measure of the long-lasting, plastic effects of meditative training on brain function.     

Heart Rate Variability During Sleep Following the Practice of Cyclic Meditation and Supine Rest

Day time activities are known to influence the sleep on the following night. Cyclic meditation (CM) has recurring cycles. Previously, the low frequency (LF) power and the ratio between low frequency and high frequency (LF/HF ratio) of the heart rate variability (HRV) decreased during and after CM but not after a comparable period of supine rest (SR). In the present study, on thirty male volunteers, CM was practiced twice in the day and after this the HRV was recorded (1) while awake and (2) during 6 h of sleep (based on EEG, EMG and EGG recordings). This was similarly recorded for the night’s sleep following the day time practice of SR. Participants were randomly assigned to the two sessions and all of them practiced both CM and SR on different days. During the night following day time CM practice there were the following changes; a decrease in heart rate, LF power (n.u.), LF/HF ratio, and an increase in the number of pairs of Normal to Normal RR intervals differing by more than 50 ms divided by total number of all NN intervals (pNN50) (P < 0.05, in all cases, comparing sleep following CM compared with sleep following SR). No change was seen on the night following SR. Hence yoga practice during the day appears to shift sympatho-vagal balance in favor of parasympathetic dominance during sleep on the following night.     

Effect of Sahaja Yoga Meditation on Auditory Evoked Potentials (AEP) and Visual Contrast Sensitivity (VCS) in Epileptics

The effect of Sahaja yoga meditation on 32 patients with primary idiopathic epilepsy on regular and maintained antiepileptic medication was studied. The patients were randomly divided into 3 groups: group I practiced Sahaja Yoga meditation twice daily for 6 months under proper guidance; group II practiced postural exercises mimicking the meditation for the same duration; and group III was the control group. Visual Contrast Sensitivity (VCS), Auditory Evoked Potentials (AEP), Brainstem Auditory Evoked Potentials (BAEP), and Mid Latency Responses (MLR) were recorded initially (0 month) and at 3 and 6 months for each group. There was a significant improvement in VCS following meditation practice in group I participants. Na, the first prominent negative peak of MLR and Pa, the positive peak following Na did not register changes in latency. The Na-Pa amplitude of MLR also showed a significant increase. There were no significant changes in the absolute and interpeak latencies of BAEP. The reduced level of stress following meditation practice may make patients more responsive to specific stimuli. Sahaja Yoga meditation appears to bring about changes in some of the electrophysiological responses studied in epileptic patients.     

The Sensorium: Psychophysiological Evaluation of Responses to a Multimodal Neurofeedback Environment

The Sensorium is a multimodal neurofeedback environment that reflects a person’s physiological state by presenting physiological signals via orchestral sounds from a speaker and multi-coloured lights projected onto a white surface. The software manages acquisition, real-time processing, storage, and sonification of various physiological signals such as the electroencephalogram (EEG) or electrocardiogram (ECG). Each of the 36 participants completed 6 interventional conditions consisting of three different Sensorium-phases with EEG and ECG feedback, a mindfulness meditation, a guided body scan exercise, and a Pseudo-Sensorium using pre-recorded data that did not reflect the subject’s own physiology. During all phases EEG, ECG, skin conductance, and respiration were recorded. A feedback questionnaire assessed the participants’ subjective reports of changes in well-being, perception, and life-spirit. The results indicate that the Sensorium sessions were not statistically inferior compared to their corresponding active control conditions with respect to improvements in subjective reports concerning well-being and perception. Additionally, the Sensorium was rated as being a more extraordinary experience, as compared to meditation. During the Sensorium conditions the EEG showed lower levels of theta2 (7–8.5 Hz), alpha (9–12 Hz) and beta (12.5–25 Hz) activity. Since participants reported benefit from the Sensorium experience regardless of any prior experience with meditation, we propose this novel method of meditative and extraordinary self-experience to be utilized as a modern alternative to more traditional forms of meditation.     

Treatment of Chronic Insomnia with Yoga: A Preliminary Study with Sleep–Wake Diaries

There is good evidence for cognitive and physiological arousal in chronic insomnia. Accordingly, clinical trial studies of insomnia treatments aimed at reducing arousal, including relaxation and meditation, have reported positive results. Yoga is a multicomponent practice that is also known to be effective in reducing arousal, although it has not been well evaluated as a treatment for insomnia. In this preliminary study, a simple daily yoga treatment was evaluated in a chronic insomnia population consisting of sleep-onset and/or sleep-maintenance insomnia and primary or secondary insomnia. Participants maintained sleep–wake diaries during a pretreatment 2-week baseline and a subsequent 8-week intervention, in which they practiced the treatment on their own following a single in-person training session with subsequent brief in-person and telephone follow-ups. Sleep efficiency (SE), total sleep time (TST), total wake time (TWT), sleep onset latency (SOL), wake time after sleep onset (WASO), number of awakenings, and sleep quality measures were derived from sleep–wake diary entries and were averaged in 2-week intervals. For 20 participants completing the protocol, statistically significant improvements were observed in SE, TST, TWT, SOL, and WASO at end-treatment as compared with pretreatment values.     

Autonomic responses to stress

Forty-eight male subjects with no previous meditative experience engaged in either progressive relaxation (PR), a meditative treatment designed to induce the relaxation response (RR), or a no-treatment control experience (C) during four sessions on consecutive days. Negative expectations regarding the effectiveness of each technique for reducing physiological responses to stress were induced for half of the subjects in each treatment condition, and positive expectations were induced for the other half. Subjects viewed a stressful film following practice of their technique during the first and fourth sessions. Heart rate and electrodermal responding were recorded continuously during practice of the techniques and during the stressful film throughout the first and fourth sessions. Results indicated lowered heart rate levels prior to the film for subjects in the PR-positive expectancy condition and during the film for subjects in the RR-positive expectancy condition. It is suggested that subjects' expectancies concerning meditation may affect cardiovascular responding during stress, although meditative treatments in general do not appear to reduce stress responding as effectively as previously suggested.This research is based upon a master's thesis submitted by the first author to the graduate school at Northern Illinois University. The research was supported in part by a grant to the second author from the graduate school at Northern Illinois University. Portions of the article were presented at the convention of the Midwestern Psychological Association in Chicago, 1978.     

Participation of pertussis toxin-sensitive GTP-binding regulatory proteins in the suppression of baroreceptor reflex by neurotensin in the rat.

We evaluated the molecular mechanism that may underlie the suppressive effect of neurotensin (NT) on the baroreceptor reflex (BRR), using Sprague-Dawley rats that were anesthetized with sodium pentobarbital (50 mg/kg, i.p.). Intracerebroventricular (i.c.v.) application of NT (15 nmol) significantly inhibited the BRR response. Such an inhibition was appreciably antagonized by pretreating animals with i.c.v. injection of pertussis toxin (10 or 20 pmol), N-ethylmaleimide (1 or 2 nmol), forskolin (30 or 60 nmol) or phorbol 12-myristate 13-acetate (2 or 4 nmol), but not by cholera toxin (15 or 30 pmol). More specifically, pretreatments with bilateral microinjection into the nucleus tractus solitarius (NTS) of pertussis toxin (80 or 160 fmol), N-ethylmaleimide (80 pmol), forskolin (480 pmol) or phorbol 12-myristate 13-acetate (16 or 32 pmol) also blunted the NT-induced suppression of BRR, although cholera toxin (120 or 240 fmol), or 1,9-dideoxyforskolin (480 pmol) had no appreciable effect. These results suggest that a pertussis toxin-sensitive guanine nucleotide-binding regulatory protein(s), which is not likely to be Gs, possibly Gi or Gp, may be involved in the transmembrane signaling process that underlies the suppression of BRR response by NT at the NTS.     

"Mind the trap": mindfulness practice reduces cognitive rigidity

Two experiments examined the relation between mindfulness practice and cognitive rigidity by using a variation of the Einstellung water jar task. Participants were required to use three hypothetical jars to obtain a specific amount of water. Initial problems were solvable by the same complex formula, but in later problems ("critical" or "trap" problems) solving was possible by an additional much simpler formula. A rigidity score was compiled through perseverance of the complex formula. In Experiment 1, experienced mindfulness meditators received significantly lower rigidity scores than non-meditators who had registered for their first meditation retreat. Similar results were obtained in randomized controlled Experiment 2 comparing non-meditators who underwent an eight meeting mindfulness program with a waiting list group. The authors conclude that mindfulness meditation reduces cognitive rigidity via the tendency to be "blinded" by experience. Results are discussed in light of the benefits of mindfulness practice regarding a reduced tendency to overlook novel and adaptive ways of responding due to past experience, both in and out of the clinical setting.     

The effect of a complex of meditation exercises on the psychophysiological state of young men

Using a simple motor response, a complex sensorimotor response, and a tapping test, the effect of a complex of meditation exercises on the neuromuscular coordination in healthy male students who were preliminarily trained in methods of self-regulation based on meditation techniques was studied. As a result of a 6-min session of self-regulation, a considerable decrease (by 30% or more) in the time of a simple motor response and a complex sensorimotor response (due to a decrease in the latent time at constant motor time) and a simultaneous decrease in the number of errors, as well as a considerable increase in the result of the tapping test, were recorded. A short-term effect expressed in an increase in the rate and accuracy of sensorimotor responses can be a result of a change in the functional state of the nervous system under the impact of transcendental meditation techniques.     

Build-up of tomato brown root rot caused by Pyrenochaeta lycopersici Schneider and Gerlach

The incidence in unheated glasshouses of tomato brown root rot (BRR) was recorded on five successive crops starting with the first ever grown on the experimental site. In the protected environment the changes followed a pattern that was defined mathematically, the regression linking angular or logit transforms of per cent BRR, observed at different intervals after planting, accounting for c. 72% of the variation. Rates of build-up, seemingly related to initial amounts of inocula, increased in successive seasons, there being more BRR in the fifth season than in the first. Four per cent BRR recorded 5 weeks after planting increased threefold during the next 3 months to 12 %, but in later years, when amounts of early-season infection were doubled to 8%, the incidence of root rot subsequently increased five times. Tomato roots colonized by Pyrenochaeta lycopersici either brown and rot or become corky. The proportion of end-of-season BRR attributable to corkiness increased from the first to fifth seasons. The monthly increments of fruit yield were inversely proportional to the incidence of BRR.     

Activation of the arousal response can impair performance on a simple motor task.

The purpose of this study was to determine the effect of arousal in men and women on the moment-to-moment performance of a simple motor task. We examined the control of a precision task in the presence and absence of imposed stressors. Twenty-nine subjects (14 men, 15 women; 18--44 yr) were randomly assigned to either a control group or one of two stressor groups, Mental Math or Electric Shock. Subjects presented with Math and Shock stressors, which lasted 10 min, experienced significant increases in cognitive and physiological arousal compared with baseline and control subjects. Heart rate, systolic blood pressure, and electrodermal activity were elevated 5--80% with presentation of the stressors, whereas diastolic blood pressure and salivary cortisol were unchanged. The greater levels of cognitive and physiological arousal were associated with reductions in steadiness of a pinch grip for the Shock subjects (approximately 130% reduction from baseline) but not for the subjects in the Math group, who experienced heightened arousal but no change in steadiness (10% reduction from baseline). Although women exhibited more of a reduction in steadiness than men, the effect was largely unrelated to the magnitude of the change in arousal.     

Women's sexual arousal: effects of high alcohol dosages and self-control instructions

The basic relationship between alcohol and women's sexual arousal – especially genital arousal – received little research attention for nearly 30 years (e.g. Wilson and Lawson, 1978) until very recently (e.g. George et al., 2009). To investigate hypotheses based on earlier findings and Alcohol Myopia Theory (AMT), two experiments evaluated the effects of high blood alcohol concentrations (BACs) and arousal instructional demands on indices of vaginal responding and self-reported sexual arousal. In Experiment 1, self-control instructions to maximize (versus suppress) arousal increased peak and average Vaginal Pulse Amplitude (VPA) change. Self-control also interacted with a target BAC of .08% (versus .00%) to influence latency to peak arousal onset: Intoxicated women instructed to maximize showed a shorter latency to peak arousal than did intoxicated women instructed to suppress; however, sober women showed an undifferentiated pattern. Also, in Experiment 1, the target BAC of .08% had no effect on VPA or subjective arousal measures. In Experiment 2, a target BAC of .10% (versus .00%) attenuated peak change and average change in VPA, but this dosage had no effects on latency to peak achieved arousal, or on subjective arousal. Instructions to maximize arousal (versus no instruction) had no effect on any arousal measures. Overall, among young moderate drinking women, alcohol had attenuating effects but only at the higher dosage. Maximize versus suppress instructions about arousal had predicted effects on arousal and interactive effects on latency, but only at the lower dosage. The findings highlight the importance of dosage and contextual factors in alcohol's impact on the variability of women's sexual responding.     

Hemodynamic Changes During Long Meditation

Changes in heart rate (HR) and blood pressure (BP) in advanced male meditators during 1 hr of meditation were compared with matched control participants resting for 1 hr. Also, changes in HR and BP during 3-hr meditation were analyzed. HR was recorded continuously during meditation (n = 38) and the control rest (n = 21). BP was measured before and after the meditation (n = 44) and the rest (n = 30). During the first hour, HR declined more in the meditators than the controls (p < .01). Within participant variability of HR was significantly lower during meditation than rest (p < .05). In the second hour of meditation, HR declined further (p = .01). BP was unaffected by either meditation or rest. In conclusion, meditation reduced the level of HR and within participant variability of HR more than rest. HR continued to decline during the second hour of meditation.