Skip to main content
PMC home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2016 Jun 24.
Published in final edited form as: Adolesc Psychiatry (Hilversum). 2015;5(2):116–124. doi: 10.2174/2210676605666150311223728

Mind-Body Practices and the Adolescent Brain: Clinical Neuroimaging Studies

Anup Sharma 1,*, Andrew B Newberg 2
PMCID: PMC4919979  NIHMSID: NIHMS794928  PMID: 27347478

Abstract

Background

Mind-Body practices constitute a large and diverse group of practices that can substantially affect neurophysiology in both healthy individuals and those with various psychiatric disorders. In spite of the growing literature on the clinical and physiological effects of mind-body practices, very little is known about their impact on central nervous system (CNS) structure and function in adolescents with psychiatric disorders.

Method

This overview highlights findings in a select group of mind-body practices including yoga postures, yoga breathing techniques and meditation practices.

Results

Mind-body practices offer novel therapeutic approaches for adolescents with psychiatric disorders. Findings from these studies provide insights into the design and implementation of neuroimaging studies for adolescents with psychiatric disorders.

Conclusions

Clinical neuroimaging studies will be critical in understanding how different practices affect disease pathogenesis and symptomatology in adolescents. Neuroimaging of mind-body practices on adolescents with psychiatric disorders will certainly be an open and exciting area of investigation.

Keywords: Breathing practices, complementary and alternative medicine, meditation, neuroimaging, yoga

INTRODUCTION

Mind-body practices constitute a large and diverse group of practices that can substantially affect neurophysiology in both healthy individuals and those with various psychiatric disorders. Examples of such practices include yoga postures, meditation interventions, tai chi, qi gong, hypnosis among many others. Over the past several decades, the neurobiological effects of mind-body practices have been incorporated into numerous theoretic models (Benson, Beary & Carol 1974; Newberg, Iverson 2003; Brown, & Gerbarg, 2005; Porges, 2007; Taylor et al., 2010). Their clinical value in psychiatric disorders is a recent but expanding area of investigation (Balasubramaniam, Telles & Doraiswamy 2012) including in adolescent patients (Black, Milam, & Sussman, 2009). In addition to the neurobiological effects, experimental studies of mind-body practices demonstrate that they can activate homeostatic mechanisms by modulating autonomic nervous system function (Bernardi, Gabutti, Porta, & Spicuzza, 2001; Brown & Gerbarg, 2005; Raghuraj, Ramakrishnan, Nagendra & Telles, 1998; Telles, Gaur, & Balkrishna, 2009), neuroendocrine responses (Fan, Tang & Posner, 2013), inflammatory activity (Weber, Arck, Mazuerk, & Klapp, 2002; Kiecolt-Glaser, Marucha, Atkinson, & Glaser, 2001) and cardiovascular function (Innes, Bourguignon, & Taylor, 2005; Innes & Vincent, 2007; Agte, Jahagirdar, & Tarwadi, 2011).

In spite of the growing literature on the clinical and physiological effects of mind-body practices, very little is known about their impact on central nervous system (CNS) structure and function in adolescents with psychiatric disorders. Neuroimaging studies have begun to identify how these practices induce such changes in adult populations. This overview highlights these findings in a select group of mind-body practices including yoga postures, yoga breathing techniques and meditation practices. Findings from these studies provide insights into the design and implementation of future neuroimaging studies with adolescents with psychiatric disorders.

GENERAL CONSIDERATIONS FOR NEUROIMAGING RESEARCH IN ADOLESCENTS

A number of practical aspects need to be considered in designing neuroimaging studies with adolescent patient populations. Among these include efforts to minimize the effects of head motion and other imaging artifacts (Johnston, Mwangi, Matthews, Coghill, & Steele, 2012). The success rate of completing single sessions of functional magnetic resonance imaging (fMRI) varies depending on the age of the subject as well as the co-morbid psychiatric disorder. A neuroimaging study with children with attention-deficit/hyperactivity disorder (ADHD) found a single session success rate of 78% compared to 96% for age and gender-matched controls. Within the ADHD group completion rates were 82% for children aged 10–12 years old compared to 70% for 7–9 year olds (Yerys et al., 2009). This study highlights the importance of modifying the number of recruited adolescents based on differences in success rates among different patient populations.

Different neuroimaging modalities have their own advantages and limitations with respect to evaluating mind-body practices in adolescents. Electroencephalography (EEG) is valuable because it is relatively non-invasive and has very high temporal resolution on the order of milliseconds. Unlike other neuroimaging modalities, it is silent and does not induce claustrophobic symptoms or require exposure to radioactivity. Moreover, it is compatible with a diverse set of body positions and is relatively tolerant of movement associated with various mind-body practices. As a modality, EEG is limited by its spatial resolution and bias towards detecting synchronized activity. It is unable to detect changes in neurotransmitter levels or brain activity deep in the CNS. Nevertheless, EEG may be particularly valuable in the study of adolescents with psychiatric disorders since it is noninvasive and poses no significant risk on these patients.

Functional MRI primarily measures changes in cerebral blood flow. In general, this is a valid method for measuring cerebral activity since a brain region that is activated during a specific task will experience a concomitant increase in blood flow. The coupling of blood flow and activity provides a method for observing which parts of the brain have increased activity (increased blood flow) and decreased activity (decreased blood flow). Functional MRI has very good spatial resolution and can be co-registered with an anatomical MRI scan that can be obtained in the same imaging session. This allows for a very accurate determination of the specific areas of the brain that are activated. FMRI also has very good temporal resolution where images can be obtained over very short time intervals, as short as a second. This allows for the detection of rapid brain activity changes. Thus, if a subject is performing several different breathing techniques sequentially while in the MRI, the differences in blood flow could be detected in each of those tasks. Finally, fMRI does not involve any radioactive exposure. Thus, it carries a very low risk and would be more acceptable to use in adolescent populations. The disadvantages of this modality are that images must be obtained while the subject is in a scanner which is a claustrophobic environment and can make up to 100 decibels of noise. This can be very distracting when individuals are performing various mind-body practices and can interfere with practices that require certain postures or body movements. However, several investigators have successfully utilized fMRI and have performed the studies by having subjects practice their mind-body technique at home while listening to a tape of the fMRI noise so that they become acclimated to the environment (Lazar et al., 2005). Currently, fMRI cannot be used to evaluate individual neurotransmitter systems.

PET and SPECT imaging modalities also have advantages and disadvantages. These include relatively good spatial resolution for PET (comparable to fMRI) and slightly worse for SPECT imaging. PET and SPECT images can also be coregistered with anatomical MRI, but this must be obtained during a separate session and therefore, matching the scans is more difficult. PET and SPECT both require the injection of a radioactive tracer. Depending on the radioactive tracer used, a variety of unique functional parameters can be measured including blood flow, metabolism (which more accurately depicts cerebral activity), and many different neurotransmitter components. The ability to measure these neurotransmitter systems is unique to PET and SPECT imaging. Such tracers can measure either state or trait responses following mind-body practices in adolescents with psychiatric disorders. Some of the more common radioactive materials such as fluorodeoxyglucose (measures glucose metabolism) can be injected through an intravenous catheter when the subject is not in the scanner. The tracer becomes “locked” in the brain during the injection period and the patient can then be scanned after completing their practice, still allowing for measurements associated with the practice. This allows for a more conducive environment for performing mind-body practices (Newberg et al., 2001). While the radioactive dose used with these modalities is fairly low, this can impose regulatory challenges in performing studies on adolescents. Another major drawback to PET and SPECT imaging is that these techniques have generally poor temporal resolution. Depending on the tracer, the resolution can be as good as several minutes or as poor as several hours or even days. It would be very difficult to use PET or SPECT to study several different meditative states in the same imaging session. However, two or three states might be measured in the same session if the appropriate radiopharmaceutical is used (Lou et al., 1999). Ultimately, the selection of neuroimaging modality in studying the effects of different mind-body practices on adolescents with psychiatric disorders will depend on the specific goals of the study. Let us consider several different mind-body practices to better evaluate the potential for developing research studies in the adolescent psychiatric population.

THE EVIDENCE BASE AND FUTURE DIRECTIONS

Yoga Postures (Asanas)

Yoga is an eight-limbed holistic system of health that includes a number of different mind-body practices. The yoga asanas are represented in the third limb of this system as organized by Patanjali (circa 400 B.C.). According to the Council for Scientific and Industrial Research (CSIR), at least 1300 different yoga postures have been described in ancient texts (Sinha, K. 2011). While the experiential effects of these poses have been described by experienced yoga instructors (Iyengar, 1977); there is a growing interest in understanding the molecular, physiological and clinical aspects of these postures. How yoga postures impact CNS activity is to date a largely unexplored area of investigation. The neuromodulatory effects of yoga postures on adolescents with psychiatric disorders remains to be determined.

Yoga postures induce functional changes in brain activity in both baseline and activated states. A small open pilot study with healthy adults looked at the effects of cerebral blood flow (CBF) before and after a 12 week training program in Iyengar Yoga (Cohen et al., 2009). Iyengar yoga uses various props to facilitate alignment and attainment of specific postures. CBF was measured in select regions of interest (ROI) corresponding to major cortical and subcortical structures. After twelve weeks of training, significant changes in the mean CBF ratio were noted in the baseline (pre- yoga session) scans in the right amygdala, right dorsal medial cortex and right sensorimotor area. After twelve weeks, the activated (post- yoga session) scans showed significantly increased activity in the right dorsal frontal lobe, right prefrontal cortex, right sensorimotor cortex, right inferior frontal lobe, right superior frontal lobe and left dorsal medial frontal lobe. The study was limited by sample size as well as the partial inclusion of breathing techniques and meditation. Despite these limitations, this preliminary study demonstrated that interventions consisting of yoga postures can result in changes in the brain’s baseline and activated states. It also correlated Iyengar yoga training with right hemispheric frontal activation, including areas involved in attention.

An important aspect related to yoga postures in the context of psychiatric disorders is their potential effect on several neurotransmitter systems. Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the CNS and is synthesized within 15–20% of cortical neurons (Markram et al., 2004; Buzsaki, Kaila & Raichle, 2007). Once released into the synaptic cleft, GABA binds to two main GABA receptor subtypes on the postsynaptic membrane, GABAA and GABAB, often resulting in neuronal hyperpolarization and inhibition. High-affinity GABA transporters (GAT) clear synaptic GABA. Altered GABAergic neurotransmission has been implicated in a number of psychiatric disorders.

Over the last thirty years, multiple lines of evidence demonstrate a low GABAergic state in mood disorders (Brambilla, Perez, Barale, Schettini, & Soares, 2003; Maciag et al., 2010; Kasa et al., 1982). Treatments found to be effective for these disorders increase GABA levels including ECT (Sanacora et al., 2003), tricyclic antidepressants (Martin et al., 1989), SSRIs (Sanacora, Mason, Rothman, & Krystal, 2002; Bhagwagar et al., 2004), lithium (Vargas, Tannhauser, & Barros, 1998), and valproate (Loscher, 1989). Moreover, specific genetic polymorphisms of the GABAA δ receptor subunit associate with childhood-onset mood disorders (COMD) (Feng et al., 2010). A small cross-sectional study examining children and adolescents (aged 9–17) with major depressive disorder found increased cortical excitability compared to healthy controls (Croarkin et al., 2013). This supports a model of excitatory dysfunction in mood disorders across the age spectrum.

There is evidence that a low GABAergic state also plays a role in the pathogenesis of anxiety disorders (Olivier, Vinkers, & Olivier 2013). Patients with panic disorder (PD), post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD) have reduced benzodiazepine binding in various brain regions compared to controls (Tiihonen et al., 1996 Malizia et al., 1998; Bremner, Innis, Southwick, et al., 2000; Bremner, Innis, White, et al., 2000). Moreover, patients with panic disorder have lower levels of cortical GABA as measured by magnetic resonance spectroscopy (MRS) compared to healthy controls (Goddard et al., 2001). Similarly, a small pilot study of patients with social anxiety disorder (SAD) found support for impaired GABAergic function and overactive glutamatergic activity (Pollack. Jensen, Simon, Kaufman, & Renshaw, 2008). Genetic polymorphisms in the GABRA2 gene interact with early childhood trauma and increase the risk of PTSD (Nelson et al., 2009). These studies support the idea that anxiety disorders are associated with low GABAergic states or excitatory dysfunction. Further clinical studies with adolescents are warranted.

ADHD is a developmental disorder characterized by a deficit in behavioral inhibition. GABA regulates motor control and impulsivity in healthy adults (Boy et al. 2010; Boy et al., 2011; Sumner, Edden, Bompas, Evans, & Singh, 2010). In a cross-sectional study using MRS, GABA concentrations were found to be significantly reduced in ADHD children (aged 8–12) compared to typically developing subjects (Edden, Crocetti, Zhu, Gilbert, & Mostofsky, 2012). These results suggest ADHD is associated with a GABAergic deficit, which may contribute to disease pathogenesis.

A systematic review of the literature finds evidence to support the role of yoga in treating symptoms of mood disorders, anxiety disorders and ADHD (Balasubramaniam et al. 2012). Given that low GABAergic activity or excitatory dysfunction is a feature of many of these disorders, one group hypothesized that yoga postures might decrease symptoms in these disorders by increasing brain GABA levels (Streeter et al., 2007). MRS can be utilized to non-invasively detect changes in endogenous GABA levels (Puts & Edden, 2012). The study compared changes in brain GABA levels following a sixty-minute yoga posture session in established yoga practitioners to changes following a sixty-minute reading session in a control group. The yoga session was associated with a 27% (p= 0.018) increase in GABA levels while the control group did not demonstrate any changes. A follow-up randomized control study of yoga-naïve subjects compared the effects of a 12-week yoga asana intervention to a metabolically matched walking intervention on symptoms of mood, anxiety and thalamic GABA levels (Streeter et al., 2010). The yoga asana intervention was associated with greater improvements in mood and anxiety, which correlated with increased thalamic GABA levels. These studies were limited by small sample sizes and excluded individuals with psychiatric disorders.

Future neuroimaging studies assessing the impact of yoga interventions on adolescents with psychiatric disorders may first focus on adolescents with mood disorders, anxiety disorders and ADHD. Assessing changes to brain activity following standardized yoga training programs will be critical in identifying brain regions affected by these mind-body practices. Following yoga training, fMRI can identify changes in brain structure and function with high spatial resolution. MRS can determine whether yoga poses can increase GABA levels in adolescents with psychiatric disorders. The use of SPECT and PET can determine whether yoga poses can affect levels of other neurotransmitters and correlate these changes with anatomical regions. Future studies could also look at different yoga posture sequences to determine their variable effects on brain activity. Concurrent clinical assessments can determine whether specific neuromodulatory effects correlate with symptomatic improvements.

Yoga Breathing Techniques

Yoga breathing techniques are self-regulatory mind-body practices that involve the voluntary control of different aspects of respiration including the length, frequency, intensity, pattern and directionality of the breath. Yoga breathing or pranayama, involves manipulation of prana, the Sanskrit term for life-force energy also known as chi in Chinese traditions. Yoga breathing encompasses a number of techniques such as paced breathing (Udo et al., 2013), resonance breathing, ujjayi breathing (Telles & Desiraju, 1991), unilateral or alternate nostril breathing (Sinha, Deepak, & Gusain, 2013), kapalabhati pranayama (Telles, Singh, & Balkrishna, 2012), Sudarshan Kriya (Zope & Zope, 2013) among many others. While initially passed down within specific teacher-to-student lineages, many of these techniques have spread widely to many regions of the world (Telles & Singh, 2013).

Preclinical studies documenting the effects of stress on adolescence (Eiland & Romeo, 2013) show that chronic stress can induce structural changes in the CNS (Oztan Aydin, & Isgor, 2001; Radley et al., 2005) and predispose to depressive behaviors (Isgor, Kabbaj, Akil, & Watson, 2004). Interventions featuring yoga breathing techniques can mitigate stress (Kjellgern, Bood, Axellson, Norlander and Saatcioglu 2007; Pilkington, Kirkwood, Rampes, & Richardson, 2005; Sharma, Sen, Singh, Bhardwaj, Kochupillai 2003; Vedamurthachar et al., 2006), rapidly alter gene expression (Qu, Olafsrud, Meza-Zepeda, & Saatcioglu, 2013), modulate autonomic nervous system activity (Telles, Maharana, Balrana, & Balkrishna, 2011; Telles, Singh, & Balkrishna, 2011) and improve cognitive performance (Telles, Joshi, & Prasoon, 2012). Theoretical models propose that these practices alter the interoceptive messages from the respiratory system to higher CNS centers via modulation of vagal activity resulting in shifts in attention, perception, emotional regulation and behavior (Streeter, Gerbarg, Saper, Ciraulo, & Brown, 2012; Brown, Gerbarg, & Muench, 2013). Initial clinical studies demonstrate that interventions featuring yoga breathing techniques can relieve symptoms of major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, panic disorder and obsessive-compulsive disorder (Brown, Gerbarg, & Muench, 2013).

Initial brain imaging studies have utilized EEG to measure the effects of different yoga breathing techniques on brain activity (Vialatte, Bakardjian, Prasad, & Cichocki, 2009). Bhramari Pranayam is a yogic breathing technique that involves placing the hands in specialized positions resulting in ear canal closure and the production of a buzzing sound with nasal exhalation. An EEG study showed that this technique can induce a localized, high frequency gamma wave activity over the left tempero-parietal lobe that remains stable during and for several minutes after the technique (Vialatte et al., 2009). Evoked potential (EP) and Event-related potential (ERP) techniques have also been employed to study the neurobiological effects of yoga breathing. These techniques involve the averaging of EEG activity time-locked to the presentation of various stimuli. Auditory evoked potentials recorded during ujjayi breathing (resistance breathing) resulted in improved transmission of auditory information at the level of the thalamus (Telles, Joseph, Venkatesh, & Desiraju, 1993). Right unilateral nostril breathing showed EP changes localized to the right cerebral and subcortical regions (Raghuraj & Telles, 2004). Following high-frequency yogic breathing (HFYB), there was a significant improvement in the P300 auditory oddball task and better performance in a letter cancellation task suggesting an improvement in attention performance (Telles, Raghuraj, Arankalle, & Naveen, 2008; Joshi & Telles, 2009). A functional near-infrared spectroscopy study showed increased deoxyhemoglobin over the dorsolateral prefrontal cortex following HFYB, suggesting activation in a region associated with attention and executive function (Telles et al., 2011).

Future neuroimaging studies assessing the impact of yoga breathing interventions on adolescent psychiatric disorders may first focus on the effects on adolescents with mood disorders, anxiety disorders, substance abuse disorders and ADHD. The application of functional neuroimaging studies will be critical in identifying the state and trait effects of these techniques with greater spatiotemporal resolution. Sudarshan Kriya Yoga (SKY), a yogic breathing technique that involves controlled, rhythmic breathing at various frequencies induces a state of restful awareness (Zope & Zope, 2013). Initial clinical studies in adults have demonstrated that this technique can reduce symptoms of major depressive disorder and anxiety disorders (Brown, Gerbarg & Muench, 2013). A study of 445 adolescents (ages 14–18) treated with a multi-component yoga program featuring SKY demonstrated significantly reduced measures of impulsivity as compared to a control group (Ghahremani et al., 2013). What role this yoga breathing technique and others may have in alleviating symptoms of adolescent psychiatric disorders remains to be determined. How these techniques modulate the structure and function of the adolescent brain is an important area of investigation.

Meditation

Meditation includes a broad number of mind-body techniques that promote self- awareness and self-regulation. Many meditation techniques can be conceptualized as falling along a continuum between two categories– focused attention (FA) meditation and open monitoring (OM) meditation. FA meditation involves bringing one’s awareness on a pre-specified sound, image or sensation as an anchoring point. An emphasis is placed on learning to identify and disengage from mental distractions and return attention onto the primary object. Overtime, practitioners develop the ability to effortlessly sustain awareness without distractions. Open monitoring meditation involves maintaining a state of unattached observation despite ongoing mental activity without focus on a specific object. A central aim of this practice is to develop a reflexive awareness of mental activity (Lutz, Slagter, Dunne, & Davidson, 2008). Specific meditation techniques can include features from both categories.

The study of meditation interventions for psychiatric disorders is an expanding area of interest. In adults, meditation interventions have been shown to improve outcomes in depression (Teasdale et al., 2000), anxiety disorders (Evans et al., 2008; Goldin & Gross, 2010; Kearney et al., 2013), substance abuse disorders (Bowen et al., 2009, Brewer et al., 2009) and pain syndromes (Kabat-Zinn, Lipworth, & Burney, 1985). In adolescents, a review of 16 clinical studies (including 11 RCTs) highlighted effectiveness of meditation interventions in anxiety, depression and ADHD (Black, Milam, & Sussman, 2009). Small to medium effects sizes were noted across the studies. These studies were limited by small sample size, diversity of participants and study-design factors.

Early imaging studies of meditation practices made substantial use of EEG (Banquet, 1973; Hirai, 1974; Hebert & Lehmann, 1977; Corby, Roth, Zarcone, & Kopell, 1978). Over the last fifty years, a large number of studies have looked at the effects of different meditation practices on adult brain EEG activity (Cahn & Polich 2006). These studies demonstrated increased alpha (8–12 Hz) activity in meditators compared to non-meditators while meditating and at rest (Golocheikine 2001, Aftanas & Golocheikine 2005). Combined EEG and fMRI-PET studies correlated increased alpha power to changes in blood flow in the inferior frontal, cingulate, superior temporal and occipital cortices (Goldman, Stern, Engel, & Cohen, 2002). In addition, a number of EEG studies reported increased theta (4–8 Hz) activity during meditation, which is associated with attention-requiring tasks (Aftanas & Golocheikine 2001, Aftanas & Golocheikine 2002). Increased frontal theta activity is believed to be generated by the anterior cingulate cortex or the dorsolateral prefrontal cortex (Asada, Fukuda, Tsunoda, Yamaguchi, & Tonoike, 1999; Ishii et al., 1999). Differences in practitioner experience, meditation techniques and study paradigms likely contributed to differences in measured EEG activity between studies (Cahn & Polich, 2006).

Neuroimaging studies have begun to identify key brain regions affected by meditation practices with greater spatial and temporal resolution. These regions can serve as a focus in determining the neurobiological effects of these practices on adolescents with psychiatric disorders. The Prefrontal Cortex (PFC) is a region of the brain with extensive connectivity with other cortical, subcortical and brain stem regions and is involved in cognition, attention and emotion (Miller & Cohen, 2001). Abnormal PFC activity has been linked to a number of psychiatric disorders (Koelkebeck et al., 2013; Britton et al., 2013; Schulte-Rüther et al., 2013). Brain imaging studies suggest that volitional tasks that require sustained attention initiate PFC activity (Ingvar 1994, Pardo, Fox & Raichle, 1991). A SPECT study of experienced Tibetan Buddhist meditators (n=8) demonstrated increased activity in the dorsolateral prefrontal cortex (DLPFC) during meditation suggesting that activation in this region is associated with volitional aspects of meditation. This study also found activation of the cingulate gyrus, thalamus, orbital and inferior frontal cortices during meditation as compared to baseline states (Newberg et al., 2001). Additional studies assessing volitional meditation practices have confirmed increased activity in prefrontal cortical areas (Hölzel et al., 2007; Engström, Pihlsgård, Lundberg, P., & Söderfeldt, 2010).

The anterior cingulate cortex (ACC) is critical for self-regulation of attention (Bush, Luu, & Posner, 2000, Ochsner et al., 2001), goal-directed behavior (Dosenbach et al., 2007) and emotional behavior (Gasoquoine, 2013). Abnormal ACC activity has been linked to psychiatric disorders including depression, obsessive-compulsive disorder, chronic pain, substance abuse and schizophrenia (Gasoquoine, 2013). In addition, recent neuroimaging of adolescents with mood and anxiety disorders demonstrate aberrant ACC activity and functional connectivity compared to control groups (Connolly et al., 2013; Britton et al., 2013; Cisler Steele, Smitherman, Lenow, & Kilts, 2013). The cingulate gyrus appears to work with the PFC in tasks involving attention (Vogt, Finch, & Olson, 1992). A fMRI study of Kundalini meditators (n=5) with at least four years experience demonstrated activation in the ACC, hippocampal and parahippocampal formation, putamen and the midbrain while in meditation compared to a control state (Lazar et al., 2000). The ACC was also activated during meditation in a SPECT study of experienced Tibetan Buddhist meditators (Newberg et al., 2001), a fMRI study of both experienced and novice meditators (Brefczynski-Lewis et al., 2007) and a fMRI study of Vipassana meditators (Hölzel et al., 2007). Short-term integrative body-mind training (IBMT), a form of mindfulness meditation, alters neural activity in the ACC and improves connectivity of the ACC to other brain regions (Tang et al., 2007; 2010; Tang, Lu, Fan, Yang, & Posner, 2012). This suggests that meditation practices can induce both short term and long-term changes in the ACC.

The insular cortex (IC), a small hidden region of cortex within the lateral sulcus, is implicated in an extensive number of cognitive functions (Nieuwenhuys, 2012) and is believed to represent the neural correlate of awareness (Craig, 2009). The IC functions with the PFC and ACC as part of an interconnected network involved in the regulation of mental activity and behavior (Cole & Schneider 2007). Furthermore, the anterior insula (AIC) is implicated in social emotions such as empathy and compassion suggesting its involvement in awareness of others (Lamm & Singer, 2010). Abnormalities in AIC structure and function has been noted in psychiatric disorders including schizophrenia (Takahasi et al., 2005), conduct disorder (Sterzer, Stadler, Poustka, & Kleinschmidt, 2007), drug addiction (Naqvi & Bechara, 2010) and elevated trait anxiety (Simmons, Strigo, Matthews, Paulus, & Stein, 2006). An fMRI study of experienced practitioners of insight meditation showed that regular practice of meditation was associated with thicker gray matter in the right AIC compared to a control group (Lazar et al., 2005). A study of experienced Vipassana meditators showed greater gray matter concentration in the regions typically activated during meditation including the right AIC (Hölzel et al., 2008). Furthermore, a study of college volunteers found a positive association between tendency for mindfulness (as measured by the Five Facet Mindfulness Questionnaire, FFMQ) and gray matter volume in the right anterior insula (Murakami et al., 2012).

The hippocampus, a limbic system structure located within the medial temporal lobe, is essential in episodic memory and spatial representations (Scoville & Milner, 1957; Eichenbaum Dudchenko, Wood, Shapiro, & Tanila, 1999; Burgess Maguire, & O’Keefe, 2002). Abnormalities in hippocampal structure and function have been described in psychiatric disorders such as post-traumatic stress disorder (Karl et al., 2006), depression (Kempton et al., 2011) and schizophrenia (Wright et al., 2000). Childhood maltreatment is also associated with altered hippocampal structure in adolescents (Whittle et al., 2013). Meditation activates the hippocampus (Lou et al., 1999; Lazar et al., 2000; Hölzel et al., 2007; Engström et al., 2010; Kalyani et al., 2011). Meditation practitioners also demonstrate larger hippocampal total volume (Luders, Kurth, Toga, Narr, & Gaser, 2013), parahippocampal gray matter volume (Leung et al., 2013) as well as enhanced fiber integrity in pathways connecting to the hippocampus (Luders, Clark, Narr, & Toga, 2011).

While neuroimaging studies have identified common areas impacted by mind-body practices, different meditation practices can also result in different brain activity profiles. A PET study of guided meditation revealed different regional activation profiles for different types of guided meditation relative to control conditions (Lou et al., 1999). An fMRI study comparing experienced practitioners of Kundalini (a type of FA meditation) or Vipassana (a type of OM meditation) revealed similar but non-overlapping cortical and sub-cortical activation during meditation compared to control conditions (Lazar et al., 2003). Moreover, the length of time during a single meditation session can affect observed brain activity profiles (Lazar et al., 2005). The comparative effects of different meditation practices, including their respective short-term and long-term effects remains to be determined.

Future neuroimaging studies assessing the impact of meditation interventions on adolescents with psychiatric disorders may first focus on adolescents with mood disorders, anxiety disorders and substance abuse disorders. Whereas interventions involving yoga postures or breathing techniques involve movement and activity; meditation interventions often do not and may initially be more challenging for adolescents. For this reason, guided meditation techniques may be needed especially for novice practitioners or early adolescents. Moreover, studies looking at the effects of different meditation techniques, including both FA and OM practices, will help determine which ones may be most compatible for adolescents with different psychiatric disorders. Given that functional neuroimaging studies in adults have identified key brain areas affected by these practices, these regions may serve as a focus in determining the impact of these practices on adolescents. Studies looking at the effects of these practices as clinical treatments will better allow for correlation of functional changes with clinical symptoms.

CONCLUSIONS

Mind-body practices offer novel therapeutic approaches for adolescents with psychiatric disorders. We have highlighted the evidence by which a subset of these practices can affect CNS structure and function. Clinical neuroimaging studies will be critical in understanding how different practices affect disease pathogenesis and symptomatology in adolescents. Studies utilizing adequate sample sizes, standardized interventions, tailored imaging modalities and concomitant clinical assessments will provide more robust and relevant data. Neuroimaging of mind-body practices on adolescents with psychiatric disorders will certainly be an open and exciting area of investigation.

Acknowledgments

Declared none.

Biographies

Anup Sharma, MD PhD is a PGY4 resident in the Department of Psychiatry at the University of Pennsylvania School of Medicine.

Andrew Newberg, MD is a Professor of Emergency Medicine and Radiology and Director of Research at the Myrna Brind Center of Integrative Medicine at the Thomas Jefferson University and Hospital

Footnotes

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

References

  1. Aftanas LI, Golocheikine SA. Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: High-resolution EEG investigation of meditation. Neuroscience Letters. 2001;310:57–60. doi: 10.1016/s0304-3940(01)02094-8. [DOI] [PubMed] [Google Scholar]
  2. Aftanas L, Golosheykin S. Impact of regular meditation practice on EEG activity at rest and during evoked negative emotions. International Journal of Neuroscience. 2005;115:893–909. doi: 10.1080/00207450590897969. [DOI] [PubMed] [Google Scholar]
  3. Agte VV, Jahagirdar MU, Tarwadi KV. The effects of Sudarshan Kriya Yoga on some physiological and biochemical parameters in mild hypertensive patients. Indian Journal of Physiology and Pharmacology. 2011;55:183–187. [PubMed] [Google Scholar]
  4. Asada H, Fukuda Y, Tsunoda S, Yamaguchi M, Tonoike M. Frontal midline theta rhythms reflect alternative activation of prefrontal cortex and anterior cingulate cortex in humans. Neuroscience Letters. 1999;274:29–32. doi: 10.1016/s0304-3940(99)00679-5. [DOI] [PubMed] [Google Scholar]
  5. Balasubramaniam M, Telles S, Doraiswamy PM. Yoga on our minds: A systematic review of yoga for neuropsychiatric disorders. Frontiers in Psychiatry. 2012;3:117. doi: 10.3389/fpsyt.2012.00117. <Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3555015/>. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Banquet JP. Spectral analysis of the EEG in meditation. Electroencephalography and Clinical Neurophysiology. 1973;35:143–151. doi: 10.1016/0013-4694(73)90170-3. [DOI] [PubMed] [Google Scholar]
  7. Bernardi L, Gabutti A, Porta C, Spicuzza L. Slow breathing reduces chemoreflex response to hypoxia and hypercapnia, and increases baroreflex sensitivity. Journal of hypertension. 2001;19:2221–2229. doi: 10.1097/00004872-200112000-00016. [DOI] [PubMed] [Google Scholar]
  8. Benson H, Beary JF, Carol MP. The relaxation response. Psychiatry. 1974;37:37–46. doi: 10.1080/00332747.1974.11023785. [DOI] [PubMed] [Google Scholar]
  9. Bhagwagar Z, Wylezinska M, Taylor M, Jezzard P, Matthews PM, Cowen PJ. Increased brain GABA concentrations following acute administration of a selective serotonin reuptake inhibitor. American Journal of Psychiatry. 2004;161:368–370. doi: 10.1176/appi.ajp.161.2.368. [DOI] [PubMed] [Google Scholar]
  10. Black DS, Milam J, Sussman S. Sitting-meditation interventions among youth: A review of treatment efficacy. Pediatrics. 2009;124:e532–541. doi: 10.1542/peds.2008-3434. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Bowen S, Chawla N, Collins SE, Witkiewitz K, Hsu S, Grow J, Marlatt A. Mindfulness-based relapse prevention for substance use disorders: A pilot efficacy trial. Substance Abuse. 2009;30:295–305. doi: 10.1080/08897070903250084. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Boy F, Evans CJ, Edden RA, Singh KD, Husain M, Sumner P. Individual differences in subconscious motor control predicted by GABA concentration in SMA. Current Biology. 2010;20:1779–1785. doi: 10.1016/j.cub.2010.09.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Boy F, Evans CJ, Edden RA, Lawrence AD, Singh KD, Husain M, Sumner P. Dorsolateral prefrontal γ-aminobutyric acid in men predicts individual differences in rash impulsivity. Biological Psychiatry. 2011;70:866–872. doi: 10.1016/j.biopsych.2011.05.030. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Brambilla P, Perez J, Barale F, Schettini G, Soares JC. GABAergic dysfunction in mood disorders. Molecular Psychiatry. 2003;8:721–737. doi: 10.1038/sj.mp.4001362. [DOI] [PubMed] [Google Scholar]
  15. Brefczynski-Lewis JA, Lutz A, Schaefer HS, Levinson DB, Davidson RJ. Neural correlates of attentional expertise in long-term meditation practitioners. Proceedings of the national Academy of Sciences. 2007;104:11483–11488. doi: 10.1073/pnas.0606552104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Bremner JD, Innis RB, Southwick SM, Staib L, Zoghbi S, Charney DS. Decreased benzodiazepine receptor binding in prefrontal cortex in combat-related posttraumatic stress disorder. The American Journal of Psychiatry. 2000;157:1120–1126. doi: 10.1176/appi.ajp.157.7.1120. [DOI] [PubMed] [Google Scholar]
  17. Bremner JD, Innis RB, White T, Fujita M, Silbersweig D, Goddard AW, Charney DS. SPECT [I-123] iomazenil measurement of the benzodiazepine receptor in panic disorder. Biological Psychiatry. 2000;47:96–106. doi: 10.1016/s0006-3223(99)00188-2. [DOI] [PubMed] [Google Scholar]
  18. Brewer JA, Sinha R, Chen JA, Michalsen RN, Babuscio TA, Nich C, Rounsaville BJ. Mindfulness training and stress reactivity in substance abuse: results from a randomized, controlled stage I pilot study. Substance Abuse. 2009;30:306–317. doi: 10.1080/08897070903250241. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Britton JC, Grillon C, Lissek S, Norcross MA, Szuhany KL, Chen G, Pine DS. Response to learned threat: An fMRI study in adolescent and adult anxiety. American Journal of Psychiatry. 2013;170:1195–1204. doi: 10.1176/appi.ajp.2013.12050651. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Brown RP, Gerbarg PL. Sudarshan Kriya yogic breathing in the treatment of stress, anxiety, and depression: Part I-neurophysiologic model. Journal of Alternative and Complementary Medicine. 2005;11:189–201. doi: 10.1089/acm.2005.11.189. [DOI] [PubMed] [Google Scholar]
  21. Brown RP, Gerbarg PL, Muench F. Breathing practices for treatment of psychiatric and stress-related medical conditions. Psychiatric Clinics of North America. 2013;36:121–140. doi: 10.1016/j.psc.2013.01.001. [DOI] [PubMed] [Google Scholar]
  22. Burgess N, Maguire EA, O’Keefe J. The human hippocampus and spatial and episodic memory. Neuron. 2002;35:625–641. doi: 10.1016/s0896-6273(02)00830-9. [DOI] [PubMed] [Google Scholar]
  23. Bush G, Luu P, Posner MI. Cognitive and emotional influences in anterior cingulate cortex. Trends in Cognitive Sciences. 2000;4:215–222. doi: 10.1016/s1364-6613(00)01483-2. [DOI] [PubMed] [Google Scholar]
  24. Buzsaki G, Kaila K, Raichle M. Inhibition and brain work. Neuron. 2007;56:771–783. doi: 10.1016/j.neuron.2007.11.008. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Cahn BR, Polich J. Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin. 2006;132:180–211. doi: 10.1037/0033-2909.132.2.180. [DOI] [PubMed] [Google Scholar]
  26. Cisler JM, Steele JS, Smitherman S, Lenow JK, Kilts CD. Neural processing correlates of assaultive violence exposure and PTSD symptoms during implicit threat processing: A network-level analysis among adolescent girls. Psychiatry Research: Neuroimaging. 2013;214:238–246. doi: 10.1016/j.pscychresns.2013.06.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Cohen DL, Wintering N, Tolles V, Townsend RR, Farrar JT, Galantino ML, Newberg AB. Cerebral blood flow effects of yoga training: preliminary evaluation of 4 cases. The Journal of Alternative and Complementary Medicine. 2009;15:9–14. doi: 10.1089/acm.2008.0008. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Cole MW, Schneider W. The cognitive control network: Integrated cortical regions with dissociable functions. Neuroimage. 2007;37:343–360. doi: 10.1016/j.neuroimage.2007.03.071. [DOI] [PubMed] [Google Scholar]
  29. Connolly CG, Wu J, Ho TC, Hoeft F, Wolkowitz O, Eisendrath S, Yang TT. Resting-state functional connectivity of subgenual anterior cingulate cortex in depressed adolescents. Biological Psychiatry. 2013;74:898–907. doi: 10.1016/j.biopsych.2013.05.036. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Corby JC, Roth WT, Zarcone VP, Kopell BS. Psychophysiological correlates of the practice of Tantric Yoga meditation. Archives of General Psychiatry. 1978;35:571–577. doi: 10.1001/archpsyc.1978.01770290053005. [DOI] [PubMed] [Google Scholar]
  31. Craig AB. How do you feel–now? The anterior insula and human awareness. Nature Reviews Neuroscience. 2009;10:59–70. doi: 10.1038/nrn2555. [DOI] [PubMed] [Google Scholar]
  32. Croarkin PE, Nakonezny PA, Husain MM, Melton T, Buyukdura JS, Kennard BD, Daskalakis ZJ. Evidence for increased glutamatergic cortical facilitation in children and adolescents with major depressive disorder. JAMA Psychiatry. 2013;70:291–299. doi: 10.1001/2013.jamapsychiatry.24. [DOI] [PubMed] [Google Scholar]
  33. Dosenbach NU, Fair DA, Miezin FM, Cohen AL, Wenger KK, Dosenbach RA, Petersen SE. Distinct brain networks for adaptive and stable task control in humans. Proceedings of the National Academy of Sciences. 2007;104:11073–11078. doi: 10.1073/pnas.0704320104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Edden RA, Crocetti D, Zhu H, Gilbert DL, Mostofsky SH. Reduced GABA concentration in attention-deficit/hyperactivity disorder. Archives of General Psychiatry. 2012;69:750–753. doi: 10.1001/archgenpsychiatry.2011.2280. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Eichenbaum H, Dudchenko P, Wood E, Shapiro M, Tanila H. The hippocampus, memory, and place cells: is it spatial memory or a memory space? Neuron. 1999;23:209–226. doi: 10.1016/s0896-6273(00)80773-4. [DOI] [PubMed] [Google Scholar]
  36. Eiland L, Romeo RD. Stress and the developing adolescent brain. Neuroscience. 2013;249:162–171. doi: 10.1016/j.neuroscience.2012.10.048. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Engström M, Pihlsgård J, Lundberg P, Söderfeldt B. Functional magnetic resonance imaging of hippocampal activation during silent mantra meditation. Journal of Alternative and Complementary Medicine. 2010;16:1253–1258. doi: 10.1089/acm.2009.0706. [DOI] [PubMed] [Google Scholar]
  38. Evans S, Ferrando S, Findler M, Stowell C, Smart C, Haglin D. Mindfulness-based cognitive therapy for generalized anxiety disorder. Journal of Anxiety Disorders. 2008;22:716–721. doi: 10.1016/j.janxdis.2007.07.005. [DOI] [PubMed] [Google Scholar]
  39. Fan Y, Tang YY, Posner MI. Cortisol level modulated by integrative meditation in a dose-dependent fashion. Stress and Health. 2014;30:65–70. doi: 10.1002/smi.2497. [DOI] [PubMed] [Google Scholar]
  40. Feng Y, Kapornai K, Kiss E, Tamás Z, Mayer L, Baji I, Barr CL. Association of the GABRD gene and childhood-onset mood disorders. Genes, Brain and Behavior. 2010;9:668–672. doi: 10.1111/j.1601-183X.2010.00598.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Ghahremani DG, Oh EY, Dean AC, Mouzakis K, Wilson KD, London ED. Effects of the Youth Empowerment Seminar on impulsive behavior in adolescents. Journal of Adolescent Health. 2013;53:139–141. doi: 10.1016/j.jadohealth.2013.02.010. [DOI] [PubMed] [Google Scholar]
  42. Goddard AW, Mason GF, Almai A, Rothman DL, Behar KL, Petroff OA, Krystal JH. Reductions in occipital cortex GABA levels in panic disorder detected with 1h-magnetic resonance spectroscopy. Archives of General Psychiatry. 2001;58:556–561. doi: 10.1001/archpsyc.58.6.556. [DOI] [PubMed] [Google Scholar]
  43. Goldin PR, Gross JJ. Effects of mindfulness-based stress reduction (MBSR) on emotion regulation in social anxiety disorder. Emotion. 2010;10:83–91. doi: 10.1037/a0018441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Goldman RI, Stern JM, Engel J, Jr, Cohen MS. Simultaneous EEG and fMRI of the alpha rhythm. Neuroreport. 2002;13:2487–2492. doi: 10.1097/01.wnr.0000047685.08940.d0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Hebert R, Lehmann D. Theta bursts: An EEG pattern in normal subjects practising the transcendental meditation technique. Electroencephalography and Clinical Neurophysiology. 1977;42:397–405. doi: 10.1016/0013-4694(77)90176-6. [DOI] [PubMed] [Google Scholar]
  46. Hirai T. Psychophysiology of Zen. Tokyo: Igaku Shoin; 1974. [Google Scholar]
  47. Hölzel BK, Carmody J, Evans KC, Hoge EA, Dusek JA, Morgan L, Lazar SW. Stress reduction correlates with structural changes in the amygdala. Social Cognitive and Affective Neuroscience. 2009;5:11–17. doi: 10.1093/scan/nsp034. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Hölzel BK, Carmody J, Vangel M, Congleton C, Yerramsetti SM, Gard T, Lazar SW. Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Research: Neuroimaging. 2011;191:36–43. doi: 10.1016/j.pscychresns.2010.08.006. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Hölzel BK, Ott U, Gard T, Hempel H, Weygandt M, Morgen K, Vaitl D. Investigation of mindfulness meditation practitioners with voxel-based morphometry. Social Cognitive and Affective Neuroscience. 2008;3:55–61. doi: 10.1093/scan/nsm038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Hölzel BK, Ott U, Hempel H, Hackl A, Wolf K, Stark R, Vaitl D. Differential engagement of anterior cingulate and adjacent medial frontal cortex in adept meditators and non-meditators. Neuroscience Letters. 2007;421:16–21. doi: 10.1016/j.neulet.2007.04.074. [DOI] [PubMed] [Google Scholar]
  51. Ingvar DH. The will of the brain: Cerebral correlates of willful acts. Journal of Theoretical Biology. 1994;171:7–12. doi: 10.1006/jtbi.1994.1206. [DOI] [PubMed] [Google Scholar]
  52. Innes KE, Bourguignon C, Taylor AG. Risk indices associated with the insulin resistance syndrome, cardiovascular disease, and possible protection with yoga: A systematic review. The Journal of the American Board of Family Practice. 2005;18:491–519. doi: 10.3122/jabfm.18.6.491. [DOI] [PubMed] [Google Scholar]
  53. Innes KE, Vincent HK. The influence of yoga-based programs on risk profiles in adults with type 2 diabetes mellitus: A systematic review. Evidence-Based Complementary and Alternative Medicine. 2007;4:469–486. doi: 10.1093/ecam/nel103. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Isgor C, Kabbaj M, Akil H, Watson SJ. Delayed effects of chronic variable stress during peripubertal-juvenile period on hippocampal morphology and on cognitive and stress axis functions in rats. Hippocampus. 2004;14:636–648. doi: 10.1002/hipo.10207. [DOI] [PubMed] [Google Scholar]
  55. Ishii R, Shinosaki K, Ukai S, Inouye T, Ishihara T, Yoshimine T, Takeda M. Medial prefrontal cortex generates frontal mid-line theta rhythm. Neuroreport. 1999;10:675–679. doi: 10.1097/00001756-199903170-00003. [DOI] [PubMed] [Google Scholar]
  56. Iyengar BKS. Light on Yoga. New York, NY: Schocken; 1977. [Google Scholar]
  57. Johnston BA, Mwangi B, Matthews K, Coghill D, Steele JD. Predictive classification of individual magnetic resonance imaging scans from children and adolescents. European Child & Adolescent Psychiatry. 2013;22:733–744. doi: 10.1007/s00787-012-0319-0. [DOI] [PubMed] [Google Scholar]
  58. Joshi M, Telles S. A nonrandomized non-naive comparative study of the effects of kapalabhati and breath awareness on event-related potentials in trained yoga practitioners. The Journal of Alternative and Complementary Medicine. 2009;15:281–285. doi: 10.1089/acm.2008.0250. [DOI] [PubMed] [Google Scholar]
  59. Kabat-Zinn J, Lipworth L, Burney R. The clinical use of mindfulness meditation for the self-regulation of chronic pain. Journal of Behavioral Medicine. 1985;8:163–190. doi: 10.1007/BF00845519. [DOI] [PubMed] [Google Scholar]
  60. Kalyani BG, Venkatasubramanian G, Arasappa R, Rao NP, Kalmady SV, Behere RV, Gangadhar BN. Neurohemodynamic correlates of ‘OM’chanting: A pilot functional magnetic resonance imaging study. International Journal of Yoga. 2011;4:3–6. doi: 10.4103/0973-6131.78171. [DOI] [PMC free article] [PubMed] [Google Scholar]
  61. Karl A, Schaefer M, Malta LS, Dörfel D, Rohleder N, Werner A. A meta-analysis of structural brain abnormalities in PTSD. Neuroscience & Biobehavioral Reviews. 2006;30:1004–1031. doi: 10.1016/j.neubiorev.2006.03.004. [DOI] [PubMed] [Google Scholar]
  62. Kasa K, Otsuki S, Yamamoto M, Sato M, Kuroda H, Ogawa N. Cerebrospinal fluid gamma-aminobutyric acid and homovanillic acid in depressive disorders. Biological psychiatry. 1982;17:877–883. [PubMed] [Google Scholar]
  63. Kearney DJ, Malte CA, McManus C, Martinez ME, Felleman B, Simpson TL. Loving-kindness meditation for post-traumatic stress disorder: A pilot study. Journal of Traumatic Stress. 2013;26:426–434. doi: 10.1002/jts.21832. [DOI] [PubMed] [Google Scholar]
  64. Kempton MJ, Salvador Z, Munafo MR, Geddes JR, Simmons A, Frangou S, Williams SC. Structural neuroimaging studies in major depressive disorder: Meta-analysis and comparison with bipolar disorder. Archives of General Psychiatry. 2011;68:675–690. doi: 10.1001/archgenpsychiatry.2011.60. [DOI] [PubMed] [Google Scholar]
  65. Kiecolt-Glaser JK, Marucha PT, Atkinson C, Glaser R. Hypnosis as a modulator of cellular immune dysregulation during acute stress. Journal of Consulting and Clinical Psychology. 2001;69:674–683. doi: 10.1037//0022-006x.69.4.674. [DOI] [PubMed] [Google Scholar]
  66. Kjellgren A, Bood SÅ, Axelsson K, Norlander T, Saatcioglu F. Wellness through a comprehensive Yogic breathing program - A controlled pilot trial. BMC Complementary and Alternative Medicine. 2007;7:43. doi: 10.1186/1472-6882-7-43. [DOI] [PMC free article] [PubMed] [Google Scholar]
  67. Koelkebeck K, Hirao K, Miyata J, Kawada R, Saze T, Dannlowski U, Murai T. Impact of gray matter reductions on theory of mind abilities in patients with schizophrenia. Social Neuroscience. 2013;8:631–639. doi: 10.1080/17470919.2013.837094. [DOI] [PubMed] [Google Scholar]
  68. Lamm C, Singer T. The role of anterior insular cortex in social emotions. Brain Structure and Function. 2010;214:579–591. doi: 10.1007/s00429-010-0251-3. [DOI] [PubMed] [Google Scholar]
  69. Lazar SW, Bush G, Gollub RL, Fricchione GL, Khalsa G, Benson H. Functional brain mapping of the relaxation response and meditation. Neuroreport. 2000;11:1581–1585. [PubMed] [Google Scholar]
  70. Lazar SW, Kerr CE, Wasserman RH, Gray JR, Greve DN, Treadway MT, Fischl B. Meditation experience is associated with increased cortical thickness. Neuroreport. 2005;16:1893–1897. doi: 10.1097/01.wnr.0000186598.66243.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
  71. Leung MK, Chan CC, Yin J, Lee CF, So KF, Lee TM. Increased gray matter volume in the right angular and posterior parahippocampal gyri in loving-kindness meditators. Social Cognitive and Affective Neuroscience. 2012;8:34–39. doi: 10.1093/scan/nss076. [DOI] [PMC free article] [PubMed] [Google Scholar]
  72. Lou HC, Kjaer TW, Friberg L, Wildschiodtz G, Holm S, Nowak M. A 15O-H2O PET study of meditation and the resting state of normal consciousness. Human Brain Mapping. 1999;7:98–105. doi: 10.1002/(SICI)1097-0193(1999)7:2&#x0003c;98::AID-HBM3&#x0003e;3.0.CO;2-M. [DOI] [PMC free article] [PubMed] [Google Scholar]
  73. Luders E, Clark K, Narr KL, Toga AW. Enhanced brain connectivity in long-term meditation practitioners. Neuroimage. 2011;57:1308–1316. doi: 10.1016/j.neuroimage.2011.05.075. [DOI] [PMC free article] [PubMed] [Google Scholar]
  74. Luders E, Kurth F, Toga AW, Narr KL, Gaser C. Meditation effects within the hippocampal complex revealed by voxel-based morphometry and cytoarchitectonic probabilistic mapping. Frontiers in Psychology. 2013;4:398. doi: 10.3389/fpsyg.2013.00398. [DOI] [PMC free article] [PubMed] [Google Scholar]
  75. Lutz A, Slagter HA, Dunne JD, Davidson RJ. Attention regulation and monitoring in meditation. Trends in Cognitive Sciences. 2008;12:163–169. doi: 10.1016/j.tics.2008.01.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
  76. Maciag D, Hughes J, O’Dwyer G, Pride Y, Stockmeier CA, Sanacora G, Rajkowska G. Reduced density of calbindin immunoreactive GABAergic neurons in the occipital cortex in major depression: relevance to neuroimaging studies. Biological Psychiatry. 2010;67:465–470. doi: 10.1016/j.biopsych.2009.10.027. [DOI] [PMC free article] [PubMed] [Google Scholar]
  77. Malizia AL, Cunningham VJ, Bell CJ, Liddle PF, Jones T, Nutt DJ. Decreased brain GABAA-benzodiazepine receptor binding in panic disorder: Preliminary results from a quantitative PET study. Archives of General Psychiatry. 1998;55:715–720. doi: 10.1001/archpsyc.55.8.715. [DOI] [PubMed] [Google Scholar]
  78. Markram H, Toledo-Rodriguez M, Wang Y, Gupta A, Silberberg G, Wu C. Interneurons of the neocortical inhibitory system. Nature Reviews Neuroscience. 2004;5:793–807. doi: 10.1038/nrn1519. [DOI] [PubMed] [Google Scholar]
  79. Martin P, Pichat P, Massol J, Soubrie P, Lloyd KG, Puech AJ. Decreased GABA B receptors in helpless rats: Reversal by tricyclic antidepressants. Neuropsychobiology. 1989;22:220–224. doi: 10.1159/000118620. [DOI] [PubMed] [Google Scholar]
  80. Miller EK, Cohen JD. An integrative theory of prefrontal cortex function. Annual Review of Neuroscience. 2001;24:167–202. doi: 10.1146/annurev.neuro.24.1.167. [DOI] [PubMed] [Google Scholar]
  81. Murakami H, Nakao T, Matsunaga M, Kasuya Y, Shinoda J, Yamada J, Ohira H. The structure of mindful brain. PloS one. 2012;7(9):e46377. doi: 10.1371/journal.pone.0046377. [DOI] [PMC free article] [PubMed] [Google Scholar]
  82. Naqvi NH, Bechara A. The insula and drug addiction: An interoceptive view of pleasure, urges, and decision-making. Brain Structure and Function. 2010;214:435–450. doi: 10.1007/s00429-010-0268-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  83. Nelson EC, Agrawal A, Pergadia ML, Lynskey MT, Todorov AA, Wang JC, Madden PA. Association of childhood trauma exposure and GABRA2 polymorphisms with risk of post-traumatic stress disorder in adults. Molecular Psychiatry. 2009;14:234–235. doi: 10.1038/mp.2008.81. [DOI] [PMC free article] [PubMed] [Google Scholar]
  84. Newberg A, Alavi A, Baime M, Pourdehnad M, Santanna J, d’Aquili E. The measurement of regional cerebral blood flow during the complex cognitive task of meditation: A preliminary SPECT study. Psychiatry Research: Neuroimaging. 2001;106:113–122. doi: 10.1016/s0925-4927(01)00074-9. [DOI] [PubMed] [Google Scholar]
  85. Newberg AB, Moss AS, Monti DA, Alavi A. Positron emission tomography in psychiatric disorders. Annals of the New York Academy of Sciences. 2011;1228(1):E13–E25. doi: 10.1111/j.1749-6632.2011.06162.x. [DOI] [PubMed] [Google Scholar]
  86. Newberg AB, Iversen J. The neural basis of the complex mental task of meditation: Neurotransmitter and neurochemical considerations. Medical hypotheses. 2003;61:282–291. doi: 10.1016/s0306-9877(03)00175-0. [DOI] [PubMed] [Google Scholar]
  87. Nieuwenhuys R. The insular cortex: A review. Progress in Brain Research. 2012;195:123–163. doi: 10.1016/B978-0-444-53860-4.00007-6. [DOI] [PubMed] [Google Scholar]
  88. Ochsner KN, Kosslyn SM, Cosgrove GR, Cassem EH, Price BH, Nierenberg AA, Rauch SL. Deficits in visual cognition and attention following bilateral anterior cingulotomy. Neuropsychologia. 2001;39:219–230. doi: 10.1016/s0028-3932(00)00114-7. [DOI] [PubMed] [Google Scholar]
  89. Olivier JD, Vinkers CH, Olivier B. The role of the serotonergic and GABA system in translational approaches in drug discovery for anxiety disorders. Frontiers in pharmacology. 2013;4:74. doi: 10.3389/fphar.2013.00074. [DOI] [PMC free article] [PubMed] [Google Scholar]
  90. Oztan O, Aydin C, Isgor C. Chronic variable physical stress during the peripubertal-juvenile period causes differential depressive and anxiogenic effects in the novelty-seeking phenotype: Functional implications for hippocampal and amygdalar brain-derived neurotrophic factor and the mossy fibre plasticity. Neuroscience. 2011;192:334–344. doi: 10.1016/j.neuroscience.2011.06.077. [DOI] [PMC free article] [PubMed] [Google Scholar]
  91. Pardo JV, Fox PT, Raichle ME. Localization of a human system for sustained attention by positron emission tomography. Nature. 1991;349:61–64. doi: 10.1038/349061a0. [DOI] [PubMed] [Google Scholar]
  92. Pilkington K, Kirkwood G, Rampes H, Richardson J. Yoga for depression: The research evidence. Journal of Affective Disorders. 2005;89:13–24. doi: 10.1016/j.jad.2005.08.013. [DOI] [PubMed] [Google Scholar]
  93. Pollack MH, Jensen JE, Simon NM, Kaufman RE, Renshaw PF. High-field MRS study of GABA, glutamate and glutamine in social anxiety disorder: response to treatment with levetiracetam. Progress in Neuro-Psychopharmacology and Biological Psychiatry. 2008;32:739–743. doi: 10.1016/j.pnpbp.2007.11.023. [DOI] [PubMed] [Google Scholar]
  94. Porges SW. The polyvagal perspective. Biological Psychology. 2007;74:116–143. doi: 10.1016/j.biopsycho.2006.06.009. [DOI] [PMC free article] [PubMed] [Google Scholar]
  95. Puts NA, Edden RA. In vivo magnetic resonance spectroscopy of GABA: A methodological review. Progress in Nuclear Magnetic Resonance Spectroscopy. 2012;60:29–41. doi: 10.1016/j.pnmrs.2011.06.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  96. Qu S, Olafsrud SM, Meza-Zepeda LA, Saatcioglu F. Rapid gene expression changes in peripheral blood lymphocytes upon practice of a comprehensive yoga program. PloS One. 2013;8(4):e61910. doi: 10.1371/journal.pone.0061910. [DOI] [PMC free article] [PubMed] [Google Scholar]
  97. Radley JJ, Rocher AB, Rodriguez A, Ehlenberger DB, Dammann M, McEwen BS, Hof PR. Repeated stress alters dendritic spine morphology in the rat medial prefrontal cortex. Journal of Comparative Neurology. 2008;507:1141–1150. doi: 10.1002/cne.21588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  98. Raghuraj P, Ramakrishnan AG, Nagendra HR, Telles S. Effect of two selected yogic breathing techniques on heart rate variability. Indian Journal of Physiology and Pharmacology. 1998;42:467–472. [PubMed] [Google Scholar]
  99. Raghuraj P, Telles S. Right uninostril yoga breathing influences ipsilateral components of middle latency auditory evoked potentials. Neurological Sciences. 2004;25:274–280. doi: 10.1007/s10072-004-0354-9. [DOI] [PubMed] [Google Scholar]
  100. Sanacora G, Mason GF, Rothman DL, Krystal JH. Increased occipital cortex GABA concentrations in depressed patients after therapy with selective serotonin reuptake inhibitors. American Journal of Psychiatry. 2002;159:663–665. doi: 10.1176/appi.ajp.159.4.663. [DOI] [PubMed] [Google Scholar]
  101. Sanacora G, Mason GF, Rothman DL, Hyder F, Ciarcia JJ, Ostroff RB, Krystal JH. Increased cortical GABA concentrations in depressed patients receiving ECT. 2014 doi: 10.1176/appi.ajp.160.3.577. [DOI] [PubMed] [Google Scholar]
  102. Scoville WB, Milner B. Loss of recent memory after bilateral hippocampal lesions. 1957. The Journal of Neuropsychiatry and Clinical Neurosciences. 1999;12:103–113. doi: 10.1176/jnp.12.1.103. [DOI] [PubMed] [Google Scholar]
  103. Simmons A, Strigo I, Matthews SC, Paulus MP, Stein MB. Anticipation of aversive visual stimuli is associated with increased insula activation in anxiety-prone subjects. Biological psychiatry. 2006;60:402–409. doi: 10.1016/j.biopsych.2006.04.038. [DOI] [PubMed] [Google Scholar]
  104. Sinha K. India pulls the plug on yoga as business. The Times of India. 2011 Feb 6; Retrieved from < http://timesofindia.indiatimes.com/international-home>.
  105. Sharma H, Sen S, Singh A, Bhardwaj NK, Kochupillai V, Singh N. Sudarshan Kriya practitioners exhibit better antioxidant status and lower blood lactate levels. Biological Psychology. 2003;63:281–291. doi: 10.1016/s0301-0511(03)00071-1. [DOI] [PubMed] [Google Scholar]
  106. Sinha AN, Deepak D, Gusain VS. Assessment of the effects of pranayama/alternate nostril breathing on the parasympathetic nervous system in young adults. Journal of Clinical and Diagnostic Research. 2013;7:821–823. doi: 10.7860/JCDR/2013/4750.2948. [DOI] [PMC free article] [PubMed] [Google Scholar]
  107. Sterzer P, Stadler C, Poustka F, Kleinschmidt A. A structural neural deficit in adolescents with conduct disorder and its association with lack of empathy. Neuroimage. 2007;37:335–342. doi: 10.1016/j.neuroimage.2007.04.043. [DOI] [PubMed] [Google Scholar]
  108. Streeter CC, Gerbarg PL, Saper RB, Ciraulo DA, Brown RP. Effects of yoga on the autonomic nervous system, gamma-aminobutyric-acid, and allostasis in epilepsy, depression, and post-traumatic stress disorder. Medical Hypotheses. 2012;78:571–579. doi: 10.1016/j.mehy.2012.01.021. [DOI] [PubMed] [Google Scholar]
  109. Streeter CC, Jensen JE, Perlmutter RM, Cabral HJ, Tian H, Terhune DB, Renshaw PF. Yoga Asana sessions increase brain GABA levels: A pilot study. The Journal of Alternative and Complementary Medicine. 2007;13:419–426. doi: 10.1089/acm.2007.6338. [DOI] [PubMed] [Google Scholar]
  110. Streeter CC, Whitfield TH, Owen L, Rein T, Karri SK, Yakhkind A, Jensen JE. Effects of yoga versus walking on mood, anxiety, and brain GABA levels: A randomized controlled MRS study. The Journal of Alternative and Complementary Medicine. 2010;16:1145–1152. doi: 10.1089/acm.2010.0007. [DOI] [PMC free article] [PubMed] [Google Scholar]
  111. Sumner P, Edden RA, Bompas A, Evans CJ, Singh KD. More GABA, less distraction: A neurochemical predictor of motor decision speed. Nature Neuroscience. 2010;13:825–827. doi: 10.1038/nn.2559. [DOI] [PubMed] [Google Scholar]
  112. Tang YY, Lu Q, Fan M, Yang Y, Posner MI. Mechanisms of white matter changes induced by meditation. Proceedings of the National Academy of Sciences. 2012;109:10570–10574. doi: 10.1073/pnas.1207817109. [DOI] [PMC free article] [PubMed] [Google Scholar]
  113. Tang YY, Lu Q, Geng X, Stein EA, Yang Y, Posner MI. Short-term meditation induces white matter changes in the anterior cingulate. Proceedings of the National Academy of Sciences. 2010;107:15649–15652. doi: 10.1073/pnas.1011043107. [DOI] [PMC free article] [PubMed] [Google Scholar]
  114. Tang YY, Ma Y, Wang J, Fan Y, Feng S, Lu Q, Posner MI. Short-term meditation training improves attention and self-regulation. Proceedings of the National Academy of Sciences. 2007;104:17152–17156. doi: 10.1073/pnas.0707678104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  115. Telles S, Gaur V, Balkrishna A. Effect of a yoga practice session and a yoga theory session on state anxiety 1. Perceptual and Motor Skills. 2009;109:924–930. doi: 10.2466/pms.109.3.924-930. [DOI] [PubMed] [Google Scholar]
  116. Telles S, Desiraju T. Oxygen consumption during pranayamic type of very slow-rate breathing. Indian Journal of Medical Research. 1991;94:357–363. [PubMed] [Google Scholar]
  117. Telles S, Joseph C, Venkatesh S, Desiraju T. Alterations of auditory middle latency evoked potentials during yogic consciously regulated breathing and attentive state of mind. International Journal of Psychophysiology. 1993;14:189–198. doi: 10.1016/0167-8760(93)90033-l. [DOI] [PubMed] [Google Scholar]
  118. Telles S, Joshi M, Dash M, Raghuraj P, Naveen KV, Nagendra HR. An evaluation of the ability to voluntarily reduce the heart rate after a month of yoga practice. Integrative Physiological and Behavioral Science. 2004;39:119–125. doi: 10.1007/BF02734277. [DOI] [PubMed] [Google Scholar]
  119. Telles S, Joshi M, Somvanshi P. Yoga breathing through a particular nostril is associated with contralateral event-related potential changes. International Journal of Yoga. 2012;5:102. doi: 10.4103/0973-6131.98220. [DOI] [PMC free article] [PubMed] [Google Scholar]
  120. Telles S, Maharana K, Balrana B, Balkrishna A. Effects Of high-frequency yoga breathing called kapalabhati compared with breath awareness on the degree of optical illusion perceived 1. Perceptual and Motor Skills. 2011;112:981–990. doi: 10.2466/02.20.22.PMS.112.3.981-990. [DOI] [PubMed] [Google Scholar]
  121. Telles S, Raghuraj P, Arankalle D, Naveen KV. Immediate effect of high-frequency yoga breathing on attention. Indian Journal of Medical Sciences. 2008;62:20–22. [PubMed] [Google Scholar]
  122. Telles S, Singh N. Science of the mind: Ancient yoga texts and modern studies. Psychiatric Clinics of North America. 2013;36:93–108. doi: 10.1016/j.psc.2013.01.010. [DOI] [PubMed] [Google Scholar]
  123. Telles S, Singh N, Balkrishna A. Heart rate variability changes during high frequency yoga breathing and breath awareness. BioPsychoSocial Medicine. 2011;5:1–7. doi: 10.1186/1751-0759-5-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  124. Telles S, Singh N, Gupta RK, Balkrishna A. Optical topography recording of cortical activity during high frequency yoga breathing and breath awareness. Medical Science Monitor. 2011;18(1):LET3–4. doi: 10.12659/msm.882189. [DOI] [PubMed] [Google Scholar]
  125. Tiihonen J, Kuikka J, Räsänen P, Lepola U, Koponen H, Liuska A, Karhu J. Cerebral benzodiazepine receptor binding and distribution in generalized anxiety disorder: A fractal analysis. Molecular Psychiatry. 1996;2:463–471. doi: 10.1038/sj.mp.4000329. [DOI] [PubMed] [Google Scholar]
  126. Udo T, Mun EY, Buckman JF, Vaschillo EG, Vaschillo B, Bates ME. Potential side effects of unhealthy lifestyle choices and health risks on basal and reactive heart rate variability in college drinkers. Journal of Studies on Alcohol and Drugs. 2013;74:787–796. doi: 10.15288/jsad.2013.74.787. [DOI] [PMC free article] [PubMed] [Google Scholar]
  127. Vargas C, Tannhauser M, Barros HMT. Dissimilar effects of lithium and valproic acid on GABA and glutamine concentrations in rat cerebrospinal fluid. General Pharmacology. 1998;30:601–604. doi: 10.1016/s0306-3623(97)00328-5. [DOI] [PubMed] [Google Scholar]
  128. Vedamurthachar A, Janakiramaiah N, Hegde JM, Shetty TK, Subbakrishna DK, Sureshbabu SV, Gangadhar BN. Antidepressant efficacy and hormonal effects of Sudarshana Kriya Yoga (SKY) in alcohol dependent individuals. Journal of Affective Disorders. 2006;94:249–253. doi: 10.1016/j.jad.2006.04.025. [DOI] [PubMed] [Google Scholar]
  129. Vialatte FB, Bakardjian H, Prasad R, Cichocki A. EEG paroxysmal gamma waves during Bhramari Pranayama: A yoga breathing technique. Consciousness and Cognition. 2009;18:977–988. doi: 10.1016/j.concog.2008.01.004. [DOI] [PubMed] [Google Scholar]
  130. Vogt BA, Finch DM, Olson CR. Functional heterogeneity in cingulate cortex: The anterior executive and posterior evaluative regions. Cerebral Cortex. 1992;2:435–443. doi: 10.1093/cercor/2.6.435-a. [DOI] [PubMed] [Google Scholar]
  131. Weber C, Arck P, Mazurek B, Klapp BF. Impact of a relaxation training on psychometric and immunologic parameters in tinnitus sufferers. Journal of Psychosomatic Research. 2002;52:29–33. doi: 10.1016/s0022-3999(01)00281-1. [DOI] [PubMed] [Google Scholar]
  132. Whittle S, Dennison M, Vijayakumar N, Simmons JG, Yücel M, Lubman DI, Allen NB. Childhood maltreatment and psychopathology affect brain development during adolescence. Journal of the American Academy of Child and Adolescent Psychiatry. 2013;52:940–952. doi: 10.1016/j.jaac.2013.06.007. [DOI] [PubMed] [Google Scholar]
  133. Wright IC, Rabe-Hesketh S, Woodruff PW, David AS, Murray RM, Bullmore ET. Meta-analysis of regional brain volumes in schizophrenia. American Journal of Psychiatry. 2000;157:16–25. doi: 10.1176/ajp.157.1.16. [DOI] [PubMed] [Google Scholar]
  134. Yerys BE, Jankowski KF, Shook D, Rosenberger LR, Barnes KA, Berl MM, Gaillard WD. The fMRI success rate of children and adolescents: typical development, epilepsy, attention deficit/hyperactivity disorder, and autism spectrum disorders. Human Brain Mapping. 2009;30:3426–3435. doi: 10.1002/hbm.20767. [DOI] [PMC free article] [PubMed] [Google Scholar]
  135. Zope SA, Zope RA. Sudarshan kriya yoga: Breathing for health. International Journal of Yoga. 2013;6:4–10. doi: 10.4103/0973-6131.105935. [DOI] [PMC free article] [PubMed] [Google Scholar]

RESOURCES