Neurobiology

Summer 2011 • Vol. 35 .No. 2 | 83

GENERATIONS – Journal of the American Society on Aging

Copyright © 2011 American Society on Aging; all rights reserved. This article may not be duplicated, reprinted or distributed in any form without written permission from the publisher: American Society on Aging, 71 Stevenson St., Suite 1450, San Francisco,CA 94105-2938; e-mail: [email protected].

In the past thirty years, scientists have ex- plored the neurobiological and clinical effects

of meditation, prayer, and related spiritual practices and experiences. Initial studies measured changes in autonomic activity, such as heart rate and blood pressure, and electroen- cephalographic changes associated with such practices. Studies have also looked at changes in hormonal and immunological function. Still other studies have exam- ined the clinical effects of meditation and prayer upon physical and psychological disorders, including hypertension, cancer, depression, and anxiety.

This article reviews the existing knowledge on the neurophysiological and clinical findings associated with religious and spiritual practices and experiences, and explores the potential health effects of these practices with regard to aging.

Neuroimaging: A Window into Meditative States Functional neuroimaging has opened a new window into the investigation of meditative states by exploring the neurological correlates of these experiences, and a growing number of imaging studies of meditative practices are now

available in the literature. The neuroimaging techniques used in these studies include posi- tron emission tomography (PET) (Herzog et al., 1990−1991; Lou et al., 1999); single photon emission computed tomography (SPECT) (Newberg et al., 2001; Newberg et al., 2003); and functional magnetic resonance imaging (fMRI)

(Lazar et al., 2000; Brefczynski-Lewis et al., 2007; Beauregard and Paquette, 2006).

Each of these techniques provides different advantages and disadvantages in the study of meditation. Though fMRI has improved resolution over SPECT and the ability of immediate anatomic correlation, it is some- times difficult to use for studying meditation because of machine noise. There is also the problem of requiring the subject to lie down— an atypical posture for many forms of medita- tion. The environment should allow subjects to have a strong meditative experience by enabling them to use the postures or actions that are part of their meditation practice. Accommodating subjects’ meditation postures is also a problem

By Andrew B. Newberg

Evidence suggests that meditation, prayer, and other related religious and spiritual practices may have significant effects on the aging brain—positive effects that may help improve memory and cognition, mood, and overall mental health.

Spirituality and the Aging Brain

Functional neuroimaging has opened a new window into the investigation of meditative states.

GENERATIONS – Journal of the American Society on Aging

84 | Summer 2011 • Volume 35 .Number 2

Pages 83–91

©American Society on Aging

when using PET imaging (which also provides better resolution than SPECT).

The process of SPECT imaging, however, allows for an injection of a radioactive tracer during a particular meditation or prayer prac- tice, which can then capture the pattern of cerebral blood flow (as it correlates with activ- ity). The problem with SPECT, though, is that only one or two states can be studied in a day. Functional MRI can measure multiple time points during the same scanning session and can capture changes in cerebral blood flow during different meditation practices, or throughout a particular practice. However, fMRI can only evaluate cerebral blood flow, while PET and SPECT can evaluate neurotransmitter systems such as serotonin and dopamine.

Though each of these functional brain imaging techniques offers important advan- tages and disadvantages for studying medita- tion, prayer, or other spiritual phenomena, the best approach may depend on a number of individual factors.

Types of Spiritual Practices There are many specific approaches to medita- tion and prayer, but they can be divided into two basic categories. The first category is one in which a person attempts to clear all thought from their sphere of attention, and includes practices such as Theravada—a form of medita- tion in which individuals attempt to reach a subjective state characterized by a sense of no space, no time, and no thought. This state is cognitively experienced as fully integrated and unified: there is no sense of a self and other.

The second category is one in which the subject focuses attention on a particular object, image, phrase, or word, and includes practices such as Transcendental Meditation and various forms of Tibetan Buddhism. This form of meditation is designed to lead to a subjective experience of absorption with the object of focus. Mindfulness meditation (Kabat-Zinn, 1991) is a practice in which attention is focused

on whatever thoughts or feelings enter the mind, and the goal is to be more aware of one’s inner mental processes.

There is also guided meditation, in which the meditation experience is guided by a leader who verbally directs the practitioner, either in person or on tape. Other meditators merely practice the meditation of their own volition. There are likely important differences between volitional (per- formed solely by the practitioner) and guided (performed with the assistance of a teacher or recording that instructs the practitioner) medita- tion practices, which should also be reflected in specific differences in cerebral activation.

Phenomenological analysis suggests that the end result of many meditation or prayer prac- tices is similar, although this result might be described differently depending upon the culture and individual. Such spiritual experiences—even mystical experiences—seem to have certain similar features (and certain distinctions). It seems reasonable that while the initial neuro- physiological activation that occurs during any given practice may differ, there may eventually be a convergence of experiences and neurophysi- ological correlates. However, the brain structures and functions described will likely apply to other types of meditation practices although the specifics will be slightly different.

Neurophysiological Changes Associated with Religious and Spiritual Practices A number of neurophysiological changes have been described in relation to meditation prac- tices and various spiritual states. Brain imaging studies suggest that willful acts and tasks that require sustained attention are initiated via activity in the prefrontal cortex (PFC) and anterior cingulate cortex (Ingvar, 1994; Frith et al., 1991; Posner and Petersen, 1990). Since practices like meditation and prayer require intense focus of attention, they also have been shown to activate these areas (Herzog et al., 1990−1991; Newberg et al., 2001; Lazar et al., 2000). A study of Tibetan Buddhist meditators

Neuroscience of the Aging Brain: Perspectives on Brain Health and Lifestyle

Summer 2011 • Volume 35 .Number 2 | 85

Pages 83–91

©American Society on Aging

showed increased activity in the PFC bilaterally (greater on the right side) and the cingulate gyrus during meditation.

Brain imaging studies of meditation practices have generally demonstrated increased thalamic activity, mediated by the excitatory neurotrans- mitter glutamate, which may be proportional to the activity in the PFC. It should also be noted that the dopaminergic system, via the basal ganglia, is believed to participate in regulating the glutamate system and the interactions between the prefrontal cortex and subcortical structures. A PET study utilizing 11C-Raclopride to measure the dopaminergic tone during Yoga Nidra meditation demonstrated a significant increase in dopamine levels during the medita- tion practice (Kjaer et al., 2002). Dopamine is also part of the reward system in the brain; this may help explain some of the positive emotional elements of meditation and prayer practices.

Another brain structure, the parietal lobe, might be involved in meditation, prayer prac- tices, and other spiritual experiences. The parietal regions are heavily involved in the analysis and integration of higher-order visual, auditory, and somaesthetic information, and are part of a complex attentional network that includes the PFC and thalamus (Fernandez- Duque and Posner, 2001). These functions of the posterior superior parietal lobe might be critical for distinguishing between the self and the external world. Changes in the orienting areas of the parietal lobe have been thought to be an important mediator in the physiology of medi- tative and spiritual experiences (Newberg and Iversen, 2003). Some studies have revealed decreased activity in the parietal lobe during meditation practices, which might be associated with the altered sense of self and space frequent- ly described by practitioners.

GENERATIONS – Journal of the American Society on Aging

86 | Summer 2011 • Volume 35 .Number 2

Pages 83–91

©American Society on Aging

In addition to the complex cortical-thalamic activity, meditation might also be expected to alter activity in the limbic system, especially since stimulation of limbic structures is associ- ated with the kind of emotional experiences similar to those described during meditation and other spiritual experiences (Fish et al., 1993; Saver and Rabin, 1997). The results of several studies, such as the fMRI study by Lazar and col- leagues, support the notion of increased activity in the regions of the amygdala and hippocampus during meditation (Lazar et al., 2000).

The hypothalamus is extensively intercon- nected with the limbic system. Stimulation of the right lateral amygdala has been shown to result in stimulation of the ventromedial portion of the hypothalamus, with a subse- quent stimulation of the peripheral parasym- pathetic system. Increased parasympathetic activity should be associated first with the subjective sensation of relaxation and eventu- ally with a more profound quiescence. Acti- vation of the parasympathetic system would also cause a reduction in heart rate and respiratory rate. All of these physiological responses have been observed during medi- tation (Jevning et al., 1992).

More recent studies have shown, however, that meditation practices are associated with a dynamic interplay between the parasympa- thetic and sympathetic nervous systems. A recent study of two separate meditative techniques suggested a mutual activation of parasympathetic and sympathetic systems by demonstrating an increase in the variability of heart rate during meditation (Peng et al., 1999). The increased variation in heart rate was hypothesized to reflect activation of both arms of the autonomic nervous system. This notion also fits the characteristic description of meditative states in which there is a sense of overwhelming calmness as well as signifi- cant alertness. Also, the notion of mutual activation of both arms of the autonomic nervous system is consistent with recent

developments in the study of autonomic interactions (Hugdahl, 1996).

Other neurotransmitters, such as serotonin and the brain’s endorphins, may also play a role in meditation practices and experiences. Drugs affecting serotonin can have hallucinatory effects such as via lysergic acid. Opiates can result in feelings of euphoria, similar to some of the experiences people have in deep meditative or spiritual states.

Given the foregoing physiological changes that might be associated with meditation, prayer, or other spiritual engagement, we can more clearly consider some of these practices’ mental health effects.

The Positive Effects of Spirituality on Mental Health A number of studies have demonstrated how religious and spiritual practices can help improve brain function in both psychological and neuro- logical conditions: the impact of these practices on mental health has been widely studied. Practices such as mindfulness meditation have generally been shown to reduce depression symptoms under a variety of circumstances. In fact, mindfulness meditation has been introduced relatively successfully into a cognitive therapy paradigm to help individuals suffering from depression. Mindfulness approaches are not considered relaxation or mood management techniques, but rather endeavors for cultivating greater self-awareness and acceptance. Practicing mindfulness has the potential to expand human perspective, understanding, and self-acceptance. Mindfulness training cultivates the ability to observe thoughts and feelings as events, similar to objects of sensory awareness, thereby helping people to respond reflectively rather than habitually or automatically.

Mindfulness meditation via the Mindfulness- Based Stress Reduction Program (MBSR) is one of the most widely studied practices and has been shown to have therapeutic benefits in several chronic illness populations, including

Neuroscience of the Aging Brain: Perspectives on Brain Health and Lifestyle

Summer 2011 • Volume 35 .Number 2 | 87

Pages 83–91

©American Society on Aging

those with mood disorders (Grossman et al., 2004). An early study of MBSR in fourteen patients with anxiety found a reduction in blood pressure and decreases in depression, anxiety, and general psychological distress in patients undergoing MBSR therapy (Kabat-Zinn, Mas- sion, and Kristeller, 1992). Meta-analyses have conflicting conclusions regarding MBSR’s efficacy in patients with mood disorders. While one review of fifteen studies on the effects of MBSR found no clear positive effects on depres- sion symptoms in patients with comorbid medical disorders or in patients with mood disorders alone (Toneatto and Nguyen, 2007), another systematic review and meta-analysis found mindfulness-based therapies to have robust within-group effect in patients with anxiety and mood disorders, results that were maintained at follow up (Hoffman et al., 2010).

A review of MBSR for its effectiveness on chronic illnesses concluded that it may help a broad range of individuals to cope with their clinical and nonclinical problems, including clinical depression, stress, and anxiety (Niazi and Niazi, 2010). Another meta-analysis of MBSR effectiveness for depression, anxiety, and psychological distress across populations with different chronic somatic diseases found a reduction of anxiety and depression in patients getting the therapy compared to wait-list controls (Bohlmeijer, Prenger, and Taal, 2010). A recent randomized wait-list control study of MBSR for patients with heterogeneous anxiety disorders found that compared to controls, the MBSR group showed medium-to-large effect sizes on measures of anxiety and a large effect size for symptoms of depression, that were maintained at six-month follow up (Vollestad, Sivertsen, and Nielsen, 2011).

The effectiveness of Mindfulness-Based Cognitive Therapy (MBCT) in chronic recur- rent depression has also been evaluated. One study comparing MBCT along with usual treatment in one group and only usual treat- ment in a control group found a decrease in reported symptoms in the MBCT group and no significant change in the usual-treatment group (Barnhofer, Crane, and Hargus, 2009). Another study found that patients who had MBCT training along with usual treatment had significantly fewer episodes of relapse or recurrence than those who did not have MBCT training (Teasdale, Segal, and Williams, 2000).

Religiosity may confer benefits for some individuals. Religious service attendance is predictive of higher life satisfaction among elders (Levin and Markides, 1988; Ho et al., 1995). Similar findings occurred in a population of

nursing home residents (House, Robbins, and Metzner, 1982). Hope and optimism seemed to run higher among religious individuals

than nonreligious individuals in some study popu- lations (Idler and Kasl, 1997a, 1997b). Using religious attendance as one of the markers of social engagement, another study determined that social disengagement was linked with cognitive decline in non-institutionalized elders (Bassuk, Glass, and Berkman, 1999). This is a longstanding problem regarding elders and religious involve- ment. It may be that people with cognitive decline participate less in social and religious activities, especially if they are confined to a nursing home. Whether this is because of the cognitive decline itself or the loss of interest in religion has not been adequately determined.

Prospective cohort studies have shown religious activity to be associated with remission of depression in Protestant and Catholic Nether- landers and ill older adults (Braam et al., 1997; Koenig, George, and Peterson, 1998). Thus, there appears to be an array of benefits from religious

Recent studies have shown that meditation practices are associated with a dynamic interplay between the parasympathetic and sympathetic nervous systems.

GENERATIONS – Journal of the American Society on Aging

88 | Summer 2011 • Volume 35 .Number 2

Pages 83–91

©American Society on Aging

and spiritual practices and experiences that benefit physical and mental health.

Meditation and Cognition Researchers have also begun to investigate the long-term effects of meditation practices on cognitive processes involved in memory; research shows that meditation practice and increased mindfulness are related to improved attention functions and cognitive flexibility (Carter et al., 2005; Jha, Krompinger, and Baime, 2007; Slagter et al., 2007; Lutz et al., 2008a, 2008b). This may have the most important implication for aging as there is a great deal of interest in helping to maintain high brain function as people age. Pagnoni and Cekic (2007) used a rapid visual presentation task to investigate age-related effects of meditation practice in meditators and non- meditators. The authors found an age-related decrease of attention performance in their meditation-naive control group, whereas no such decrease was present in meditators. Chan and Woollacott (2007) compared the effects of meditation practice on the Stroop task (which measures executive network) and Global−Local Letters task (which measures orientation net- work) and found that meditation practice was associated with increased efficiency of the executive attention network, but had no effect on the orienting network.

Moore and Malinowski (2009) compared meditators with a meditation-naive control group on tasks that measure cognitive flexibility and speed of processing visual information and found that meditators outperformed non-meditators on all measures. Also, performance was positive- ly correlated to participants’ self-reported scores on the levels of mindfulness measures. A similar pattern of results was reported by Valentine and Sweet (1999) who found that long-term medita- tion practitioners scored significantly higher on a test of sustained attention than short-term

meditators and non-meditators. Collectively, these findings suggest that meditation practice affects cognitive function and that the beneficial effects of meditation are moderated by intensity and length of training.

Several other studies have also pointed out the potential effects of meditation on memory and cognition. Chambers, Lo, and Allen (2008) examined the impact of a ten-day Vipassana meditation retreat on novice meditators’ work- ing memory capacity, response time on a novel attention task requiring participants to attend and update information between two categories (e.g., food and household objects, or positive and negative affective words), and five self-report measures of cognitive processes and affect. They found that meditation training increased mindfulness, enhanced working memory capacity, reduced switch costs in the attention task, and reduced anxiety, negative affect, and depression.

Tang et al. (2007) examined the impact of five days of integrative body-mind training (IBMT) on measures assessing visual reasoning, mood, and physiological responses to stress. This training is an approach to meditation that stresses no effort to control thoughts, but has the goal of creating a state of restful alertness. The authors found that meditation benefited performance in conflict monitoring and reasoning. They also found that meditation reduced anxiety, depression, anger, and fatigue, and increased stress regulation. In

contrast, Jha, Krompinger, and Baime (2007) examined the impact of participation in an eight-week MBSR course and found that a group of novice meditators who underwent meditation training had improved performance in orienting their attention.

We recently performed a study that used a type of meditation called Kirtan Kriya in which

Meditation practice and increased mindfulness are related to improved attention functions and cognitive flexibility.

Neuroscience of the Aging Brain: Perspectives on Brain Health and Lifestyle

Summer 2011 • Volume 35 .Number 2 | 89

Pages 83–91

©American Society on Aging

the individual repetitively vocalizes consonant- vowel combinations (“sa, ta, na, ma”) while touching their thumb to each of their fingers in sequence (Newberg et al., 2010). The practice takes twelve minutes per day, and our subjects were asked to perform the practice for eight weeks. Before and after the eight-week meditation program, subjects were evaluated using brain imaging and also cognitive testing. Overall, we found significant increases in blood flow in the frontal lobes, which are involved with our ability to focus attention. We found approximately a 10 percent improvement in verbal memory and general cognitive function. Overall, there does seem to be some important effects of meditation on cognition, but more research is needed to elucidate how and why these effects occur.

Negative Effects of Meditation and Spirituality on Health Although most studies have shown positive effects of meditation, religious practices, and spirituality, they may cause a negative impact on health. Meditation’s most common detrimental effect is usually frustration: the practitioner struggles to perform the meditation practice. This might be for a variety of reasons, from not being able to follow the instructions properly, or trying to meditate in a distracting environment, to the individual not enjoying the practice. As this frustration can turn to embarrassment and anxiety, it is important that individuals try to do meditation practices that they feel comfortable with and can perform with relative ease. While

rare, there are some cases in which intense meditation has caused people to have dissocia- tive experiences, which can be frightening. Such experiences, however, usually do not occur unless the practice is performed for many hours a day over a period of years.

Even positive experiences can sometimes have damaging effects if an individual has problems incorporating them into their current religious or spiritual belief system. Such a dichotomy can lead to anxiety and depression if it sparks a “spiritual crisis.” Additionally, self- perceived religious transgressions can cause emotional and psychological anguish. When a mix of religious, spiritual, and organic sources is causing mental illness, treatment can become complicated. Healthcare workers must properly balance treating each source.

Existing evidence suggests that meditation, prayer, and other related religious and spiritual practices may have significant effects on the aging brain. Many of these effects appear to be positive, helping to improve memory and cognition, mood, and overall mental health. However, there are potential negative effects that must also be considered when beginning a particular practice. We will look to future research that may better delineate the physiological and clinical effects of these spiritual practices.

Andrew B. Newberg, M.D., is director of research at the Jefferson-Myrna Brind Center of Integrative Medicine, Thomas Jefferson University in Philadelphia.

References Barnhofer, T., Crane, C., and Hargus, E. 2009. “Mindfulness- based Cognitive Therapy as a Treatment for Chronic Depression: A Preliminary Study.” Behavioral Research in Therapy 47: 366−73.

Bassuk, S. S., Glass, T. A., and Berkman, L. F. 1999. “Social Disengagement and Incident Cognitive Decline in Community- Dwelling Elderly Persons.” Annals of Internal Medicine 131: 165−73.

Beauregard, M., and Paquette, V. 2006. “Neural Correlates of a Mystical Experience in Carmelite Nuns.” Neuroscience Letters 405(3): 186−90.

GENERATIONS – Journal of the American Society on Aging

90 | Summer 2011 • Volume 35 .Number 2

Pages 83–91

©American Society on Aging

Boey, K. W. 2003. “Religiosity and Psychological Well-Being of Older Women in Hong Kong.” Interna- tional Journal of Psychiatric Nursing Research 8: 921−35.

Bohlmeijer, E., Prenger, R., and Taal, E. 2010. “The Effects of Mindfulness-Based Stress Reduc- tion Therapy on Mental Health of Adults with a Chronic Medical Disease: A Meta-Analysis.” Journal of Psychosomatic Research 68(6): 539−44.

Braam, A. W., et al. 1997. “Religios- ity as a Protective or Prognostic Factor of Depression in Later Life; Results from a Community Survey in The Netherlands.” Acta Psychia- try Scandinavia 96: 199−205.

Brefczynski-Lewis, J. A., et al. 2007. “Neural Correlates of Attentional Expertise in Long- Term Meditation Practitioners.” Proceedings of the National Academy of Sciences of the United States of America 104(27): 11483−8.

Carter, O. L., et al. 2005. “Medita- tion Alters Perceptual Rivalry in Tibetan Buddhist Monks.” Current Biology 15: R412−13.

Chambers, R., Lo, B. C. Y., and Allen, N. B. 2008. “The Impact of Intensive Mindfulness Training on Attentional Control, Cognitive Style and Affect.” Cognitive Therapy and Research 32: 303–22.

Chan, D., and Woollacott, M. 2007. “Effects of Level of Meditation Experience on Attentional Focus: Is the Efficiency of Executive or Orientation Networks Improved?” The Journal of Alternative and Complementary Medicine 13: 651−7.

Fernandez-Duque, D., and Posner, M. I. 2001. “Brain Imaging of Attentional Networks in Normal and Pathological States. Journal of Clinical and Experimental Neuro- psychology 23: 74−93.

Idler, E. L., and Kasl, S. V. 1997a. “Religion Among Disabled and Nondisabled Persons II: Atten- dance at Religious Services as a Predictor of the Course of Disabil- ity.” Journals of Gerontology, Series B: Psychological Sciences and Social Sciences 52: S306−16.

Idler, E. L., and Kasl, S. V. 1997b. “Religion Among Disabled and Nondisabled Persons I: Cross- Sectional Patterns in Health Practices, Social Activities, and Well-Being.” Journals of Geron- tology, Series B: Psychological Sciences and Social Sciences 52: S294−305.

Ingvar, D. H. 1994. “The Will of the Brain: Cerebral Correlates of Willful Acts.” Journal of Theoretical Biology 171: 7−12.

Jevning, R., Wallace R. K., and Beidebach, M. 1992. “The Physiol- ogy of Meditation: A Review. A Wakeful Hypometabolic Integrated Response.” Neuroscience and Biobehavioral Reviews 16: 415−24.

Jha, A. P., Krompinger, J., and Baime, M. J. 2007. “Mindfulness Training Modifies Subsystems of Attention.” Cognitive, Affective, & Behavioral Neuroscience 7: 109−19.

Kabat-Zinn, J. 1991. Full Catas- trophe Living: How to Cope with Stress, Pain and Illness Using Mindfulness Meditation. New York: Delta.

Kabat-Zinn, J., Massion, A. O., and Kristeller, J. 1992. “Effectiveness of a Meditation-Based Stress Reduc- tion Program in the Treatment of Anxiety Disorders.” American Journal of Psychiatry 149: 936−43.

Kark, J. D., et al. 1996. “Psychoso- cial Factors Among Members of Religious and Secular Kibbutzim.” Israel Journal of Medical Sciences 32: 185−94.

Fish, D. R., et al. 1993. “Clinical Responses to Electrical Brain Stimulation of the Temporal and Frontal Lobes in Patients with Epilepsy.” Brain 116: 397−414.

Frith C. D., et al. 1991. “Willed Action and the Prefrontal Cortex in Man. A Study with PET.” Proceed- ings of the Royal Society of London 244: 241−6.

Grossman, P., et al. 2004. “Mindful- ness-based Stress Reduction and Health Benefits: A Meta-Analysis.” Journal of Psychosomatic Research 57(1): 35−43.

Herzog, H., et al. 1990−1991. “Changed Pattern of Regional Glucose Metabolism During Yoga Meditative Relaxation.” Neuropsy- chobiology 23: 182−7.

Ho, S. C., et al. 1995. “Life Satisfac- tion and Associated Factors in Older Hong Kong Chinese.” Journal of the American Geriatrics Society 43: 252–5.

Hofmann, S. G., et al. 2010. “The Effect of Mindfulness-Based Therapy on Anxiety and Depres- sion: A Meta-Analytic Review.” Journal of Consultative and Clinical Psychology 78: 169–183.

House, J. S., Robbins, C., and Metzner, H. L. 1982. “The Associa- tion Of Social Relationships and Activities with Mortality: Prospec- tive Evidence from the Tecumseh Community Health Study.” American Journal of Epidemiology 116: 123−40.

Hugdahl, K. 1996. “Cognitive Influences on Human Autonomic Nervous System Function.” Current Opinion in Neurobiology 6: 252−8.

Neuroscience of the Aging Brain: Perspectives on Brain Health and Lifestyle

Summer 2011 • Volume 35 .Number 2 | 91

Pages 83–91

©American Society on Aging

Kjaer, T., et al. 2002. “Increased Dopamine Tone During Medita- tion-Induced Change of Conscious- ness.” Cognitive Brain Research 13(2): 255−9.

Koenig, H. G., George, L. K., and Peterson, B. L. 1998. “Religiosity and Remission of Depression in Medically Ill Older Patients.” American Journal of Psychiatry 155: 536−42.

Lazar, S. W., et al. 2000. “Function- al Brain Mapping of the Relaxation Response and Meditation.” NeuroReport 11: 1581−5.

Lazar, S. W., et al. 2005. “Medita- tion Experience Is Associated with Increased Cortical Thickness.” NeuroReport 16: 1893−7.

Levin, J., and Markides, K. 1988. “Religious Attendance and Psychological Well-Being in Middle-Aged and Older Mexican Americans.” Sociological Analysis 49: 66−72.

Lou, H. C., et al. 1999. “A 15O-H2O PET Study of Meditation and the Resting State of Normal Conscious- ness.” Human Brain Mapping 7: 98−105.

Lutz, A., et al. 2008a. “Regulation of the Neural Circuitry of Emotion by Compassion Meditation: Effects of Meditative Expertise.” PLoS ONE 26: e1897.

Lutz, A., et al. 2008b. “Attention Regulation and Monitoring in Meditation.” Trends in Cognitive Sciences 12: 163−9.

Moore, A., and Malinowski, P. 2009. “Meditation, Mindfulness and Cognitive Flexibility.” Conscious- ness and Cognition: An Internation- al Journal 18: 176−186.

Slagter, H. A., et al. 2007. “Mental Training Affects Distribution of Limited Brain Resources.” Public Library of Science Biology 5: 1228−35.

Tang, Y., et al. 2007. “Short-term Meditation Training Improves Attention and Self-Regulation.” Proceedings of the National Academy of Sciences of the United States of America 104: 17152−6.

Teasdale, J. D., Segal, Z. V., and Williams, J. M. 2000. “Prevention of Relapse/Recurrence in Major Depression by Mindfulness-Based Cognitive Therapy.” Journal of Consultative and Clinical Psychol- ogy 68: 615−23.

Toneatto, T., and Nguyen, L. 2007. “Does Mindfulness Meditation Improve Anxiety and Mood Symptoms? A Review of the Controlled Research.” Canadian Journal of Psychiatry 52(4): 260−6.

Valentine, E. R., and Sweet, P. L. G. 1999. “Meditation and Attention: A Comparison of the Effects of Concentrative and Mindfulness Meditation on Sustained Atten- tion.” Mental Health, Religion and Culture 2: 59−70.

Vollestad, J., Sivertsen, B., and Nielsen, G. H. 2011. “Mindfulness- Based Stress Reduction for Patients with Anxiety Disorders: Evaluation in a Randomized Controlled Trial.” Behavioral Research in Therapy 49: 281−8.

Newberg, A. B. 2010. “Meditation Effects on Cognitive Function and Cerebral Blood Flow in Subjects with Memory Loss: A Preliminary Study.” Journal of Alzheimer’s Disease 20(2): 517–26.

Newberg, A. B., and Iversen, J. 2003. “The Neural Basis of the Complex Mental Task of Medita- tion: Neurotransmitter and Neurochemical Considerations.” Medical Hypotheses 61(2): 282−91.

Newberg, A. B., et al. 2001. “The Measurement of Regional Cerebral Blood Flow During the Complex Cognitive Task of Meditation: A Preliminary SPECT Study.” Psychiatry Research: Neuroimaging 106: 113−22.

Newberg, A. B., et al. 2003. “Cerebral Blood Flow During Meditative Prayer: Preliminary Findings and Methodological Issues.” Perceptual and Motor Skills 97(2): 625−30.

Niazi, A. K., and Niazi, S. K. 2010. “Mindfulness-Based Stress Reduction: A Non-Pharmacological Approach for Chronic Illness.” North American Journal of Medical Science 3: 20−23.

Pagnoni, G., and Cekic, M. 2007. “Age Effects on Gray Matter Volume and Attentional Perfor- mance in Zen Meditation.” Neurobiology of Aging 28: 1623−7.

Peng, C. K., et al. 1999. “Exagger- ated Heart Rate Oscillations During Two Meditation Tech- niques.” International Journal of Cardiology 70: 101−7.

Posner, M. I., and Petersen, S. E. 1990. “The Attention System of the Human Brain.” Annual Review of Neuroscience 1990 13: 25−42.

Saver, J. L., and Rabin, J. 1997. “The Neural Substrates of Religious Experience.” The Journal of Neuropsychiatry and Clinical Neurosciences 9: 498−510.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.