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She desire to take control over our bodies and control our weight has created many food-related industries. Several of these alone cost untold billions of dollars a year. We try diets, specialty foods, fads, surgeries and a slew of other methods. Some people seek complementary treatments such as physical exercise, hypnotherapy and acupuncture. Having years of experience in helping clients with weight control I can say outright that I do not believe any modality in itself is a solution. I do not believe there is any silver bullet. Weight control is a multifaceted issue and it requires in-depth, multi-layered solutions.

There are excellent supports. Acupuncture is a great tool for weight control, but not in the way most people think of it. There are no acupuncture points to permanently control overeating, binging or addiction of any kind. Some points support release of addiction, but that is a far cry from being a solution.

When it comes to weight control many holistic health care professionals hear: “this is broken, please fix it,” which generally translates to “a part of me is broken and you are the therapist so please fix me.” Success will only come when this approach to support changes dramatically.

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Here are nine points to help a client seeking weight control through acupuncture or any other modality:

1. The treatment, be it acupuncture, hypnotherapy, or other is a support modality. In and of itself it is not a solution.

2. No matter what treatment a person seeks, if the underlying emotions and habits remain, the world’s greatest treatments are doomed.

3. To release weight and permanently control it, an individual must redefine their relationship to food.

4. In most cases the client must be willing to release the emotional hold of food as well as the physiological..

5. A person seeking to change bad eating habits will have a greater likelihood of permanent success if they view the problem as one of addiction. Unlike other addictions such as smoking or drugs, we all must eat to survive. This means food cannot be viewed as an ‘enemy.’

Which brings me to my final points about weight control:

6. Success is not linked to a diet. The subject of diets and overeating is too large to handle here. Suffice it to say that there tends to be a converse relationship between the two — more dieting leads to more difficulty with controlling weight, not less.

7. It bears repeating: The enemy is NOT food! That belief leads to feeling helpless, which supports addictive behavior and bad habits.

8. The enemy is feeling ugly and depressed because of overweight. It is feeling like a failure because we lost the battle once again with the refrigerator demons. The enemy is loss of spirit and loss of heart because the journey feels too long, the goal too far.

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9. SUCCESS is linked to self-acceptance, self-knowledge, and personal responsibility. It is knowing that the journey begins with a small step and that while there may be occasional straying, as long as the way is forward, all is well. It is linked to a willingness to leave old beliefs and habits that no longer support us and actively seek ones that do.

Seeking help with acupuncture or another healthy modality as a support is valuable. Vastly more important is accepting that lasting change is up to you. As with all personal journeys the greatest reward is often in what we learn along the way. Weight control opens the door to many changes. Success is measured not only in pounds shed, but in the awareness that we are more conscious and confident and able to experience life on our terms.

The winnowing down of 664 studies to a mere 10 that compared “real” to &quotsham” acupuncture may have selected for criteria that excluded studies that may have shown real and positive effects.
It may also be indicative of selection bias. For example, 18 studies used animals, 52 were uncontrolled trials, and 172 were excluded because they did not use sham or placebo control. One hundred twenty-one studies compared 2 different types of acupuncture treatment. It is possible that some of these studies may have demonstrated more favorable effects.

For example, in 1997, researchers Hopwood and Lewith published a preliminary study of 6 patients who had suffered strokes within 3 months of acupuncture treatment.2 Each patient was treated daily for 2 weeks with electroacupuncture, with a 2-week crossover period during which the patients were treated with placebo electrotherapy. A consistent rise in motor function as assessed by the Motricity Index was observed after the electroacupuncture treatments, leading the authors to conclude that acupuncture can have salutary effects on patients recovering from stroke.

It is notable that while the study authors did not find statistical significance to the results of their analysis, specific analyses of activities of daily living showed a slight trend toward improvement favoring those treated with real acupuncture versus sham acupuncture.

While this is an exhaustive overview of studies evaluating the effects of acupuncture on post-stroke recovery and an important study in the field, clearly more research is needed, especially where patients are offered treatment as close to their stroke as possible.

Design
Meta-analysis of randomized controlled trials comparing the effects of acupuncture with sham acupuncture. Ten of 664 potentially relevant studies met inclusion criteria. For acute and subacute stages post-stroke, authors included 7 trials.

Results
Meta-analysis of 5 studies that accessed functionality did not show a significant difference in favor of acupuncture, with high heterogeneity. A post-hoc sensitivity analysis of 3 trials with low risk of bias did not show beneficial effects of acupuncture on activities of daily living at the end of the intervention period. For the chronic stage after stroke, 3 trials tested effects of acupuncture on function according to Modified Ashworth Scale; all failed to show favorable effects.

Interpretation
Meta-analyses of data from rigorous randomized sham-controlled trails did not show a positive effect of acupuncture as a treatment for functional recovery after stroke. Few randomized sham-controlled studies have tested the effectiveness of acupuncture during stroke rehabilitation.

Discussion
According to the authors of this study, there are several possible explanations of these findings: acupuncture may be ineffective, existing studies may have been inadequately designed, or treatment may not have been properly administered. For example, several of the trials included patients treated more than 6 months post-stroke, which may be too long after injury to expect to see significant improvements. Additionally, treatment protocols varied significantly in terms of the types of acupuncture treatments applied, whether or not electro-acupuncture was included, number and frequency of visits, and other treatment variables.

It is laudable that the authors did not use English language studies exclusively but instead did exhaustive research to include all clinically relevant trials they could find, including those from China, Japan, and Korea where acupuncture is used much more frequently than in the West for post-stroke treatment and often much closer to the stroke event than in the West, which could potentially yield more positive results.For example, over my 21-plus years as a licensed acupuncturist, I have only treated a relative handful of patients for post-stroke recovery, and all of them were at least 6 months past the dates of their strokes, significantly limiting expected treatment effectiveness.

While this meta-analysis is the most comprehensive I have reviewed, I have some concerns with the study design. In their interpretation, the authors admit that sham acupuncture is not inert and has been shown to cause physiological effects.1 The winnowing down of 664 studies to a mere 10 that compared “real” to “sham” acupuncture may have selected for criteria that excluded studies that may have shown real and positive effects.

The small sample size in the yoga group where only a nearly significant increase in thalamic GABA levels was detected was a limitation, which was offset by the findings of significant correlations between GABA levels and mood and anxiety scores. In our previous study, the acute increase in whole-slab GABA levels in experienced yoga practitioners was 27% (published) and a 26% increase in thalamic GABA levels (unpublished), compared to a 13% thalamic increase seen in the current study of yoga-naı¨ve subjects who were trained for 12 weeks.

This suggests that while subjects can be trained to practice yoga in a relatively short time with a measurable effect, the associated change in GABA levels may increase with experience. The effect of the yoga intervention on GABA levels may be due to the ability of yoga practices to increase parasympathetic nervous system (PNS) activity. In a study comparing Iyengar yoga to a walking control, the Iyengar yoga group showed greater increases in PNS activity. Yoga techniques and vagal nerve stimulation (VNS) increase PNS tone by stimulating vagal afferents. Studies suggest that the antiepileptic effects of VNS are largely mediated by widespread release of GABA. Accordingly, the practice of yoga through stimulation of vagal afferents may result in the increase of brain GABA levels as seen in the yoga group.

Conclusions
The 12-week yoga intervention was associated with greater improvements in mood and anxiety than a metabolically matched walking exercise. This is the first study to demonstrate that increased thalamic GABA levels are associated improved mood and decreased anxiety. It is also the first time that yoga postures have been associated with a positive correlation between acute increases in thalamic GABA levels and improvements in mean scores on mood and anxiety scales. Given that pharmacologic agents that increase the activity of the GABA system are prescribed to improve mood and decrease anxiety, the reported correlations are in the expected direction. The possible role of GABA in mediating the beneficial effects of yoga on mood and anxiety warrants further study.

In this study, the yoga intervention was associated with greater improvements in mood and decreases in anxiety in the tonic, acute and intervention analyses compared to the metabolically matched walking intervention, suggesting that the effect of yoga on mood and anxiety is not solely due to the metabolic demands of the activity. In our prior study, significant acute increases in brain GABA levels immediately after a yoga session were recorded. The current study found near-significant acute increases, but stable tonic levels during the 12-week yoga intervention. These observations are consistent with a time-limited effect of the yoga intervention on thalamic GABA levels.

The lack of tonic changes in this study, and the lack of baseline differences between the experienced yoga practitioners and controls in the prior study, suggest that tonic GABA levels are stable in subjects screened to exclude low GABA states. The whole group analysis of the correlations between mood and anxiety scales taken before each scan and the GABA levels obtained from those scans demonstrated significant positive correlations with the positive scales of Tranquility and Revitalization and a negative correlation with the STAI-State. To our knowledge, this is the first study to report a positive correlation between thalamic GABA levels and improved mood or decreased anxiety. The correlations between group changes in mood and anxiety scores and changes in GABA levels in the tonic and acute conditions suggest that increases in thalamic GABA levels are associated with improved mood and decreased anxiety.

This is the first study to show that a behavioral intervention (i.e., yoga) is associated with a positive correlation between changes in thalamic GABA levels and improvements in mood and anxiety. The use of METs controlled for metabolic demands of each intervention and allowed the activity level of the 2 groups (outside of the intervention) to be compared. The significantly greater level of physical activity outside the intervention in the walking group compared to the yoga group was not expected. The higher level of outside activity in the walking group could have contributed to the finding of smaller changes in mood and anxiety in the walking group, as the intervention may not have been a great enough physical challenge given the greater level of outside activity.

In the GEE analysis, the yoga group showed increased scores over the course of the intervention in the three positive EIFI subscales (Positive Engagement, Revitalization, and Tranquility), while the walking group showed an increase in the EIFI-Revitalization subscale. The yoga group showed a decrease in the STAI-State score, indicating decreased anxiety. The between-group analysis showed the yoga group to have greater increases in all positive scales and greater decreases in all negative scales compared with the walking group, indicating improved mood, decreased anxiety and decreased exhaustion.

Tonic changes in mean mood scores showed significant increases in the yoga group for Revitalization (1.8_2.5, tј3.21, dfј18, pј0.005). Acute changes in mean scores indicated significant increases in the yoga group for Revitalization (2.5_2.7, tј4.12, dfј18, p<0.001) and Tranquility (2.0_1.8, tј4.77, dfј18, p<0.001), and significant decrease in the STAI-State (_5.2_5.5, tј_4.05, dfј17, p<0.001). There were no significant tonic or acute changes detected in the walking group. Analysis of the gray matter/white matter ratio in the thalamic voxel was done for each of the three scans.

There was no difference in the average gray matter/white matter ratio among the three scans for the thalamus (Fј0.11, dfј2, pј0.90), indicating consistent repositioning of the voxel over the same anatomical region for each scan. There was no difference between the yoga and walking group in baseline GABA levels (tј0.73, dfј32, pј0.47). There were no significant changes in tonic GABA levels in either group. There as a nearly significant increase in acute thalamic GABA levels in the yoga group (0.009_0.019, tј1.80, dfј17, pј0.09) (Fig. 2 and Table 3). Whether thalamic GABA levels correlate with improved mood or decreased anxiety is a general question, independent of group assignment. Therefore, the correlation of mood and anxiety scores with GABA levels was done for the whole group. There were significant positive correlations of GABA levels with Revitalization and Tranquility scores and a negative correlation with the STAI-State scores (Table 4). In the yoga group, for the tonic condition, there were positive correlations of changes in mood and anxiety scores with changes in mean GABA levels for Revitalization and Tranquility scores and a negative correlation with the STAIState, while in the acute condition there were positive correlations with Tranquility scores (Table 4). Women (nј22) used an approved method of birth control and had negative urine pregnancy tests prior to each imaging session. Because decreases in GABA levels occur during the follicular phase, women were scheduled for scanning in the nonluteal stage defined by a serum progesterone

Discussion
In this study, the yoga intervention was associated with greater improvements in mood and decreases in anxiety in the tonic, acute and intervention analyses compared to the metabolically matched walking intervention, suggesting that the effect of yoga on mood and anxiety is not solely due to the metabolic demands of the activity. In our prior study, significant acute increases in brain GABA levels immediately after a yoga session were recorded. The current study found near-significant acute increases, but stable tonic levels during the 12-week yoga intervention. These observations are consistent with a time-limited effect of the yoga intervention on thalamic GABA levels. The lack of tonic changes in this study, and the lack of baseline differences between the experienced yoga practitioners and controls in the prior study, suggest that tonic GABA levels are stable in subjects screened to exclude low GABA states. The whole group analysis of the correlations between mood and anxiety scales taken before each scan and the GABA levels obtained from those scans demonstrated significant positive correlations with the positive scales of Tranquility and Revitalization and a negative correlation with the STAI-State. To our knowledge, this is the first study to report a positive correlation between thalamic GABA levels and improved mood or decreased anxiety.

The correlations between group changes in mood and anxiety scores and changes in GABA levels in the tonic and acute conditions suggest that increases in thalamic GABA levels are associated with improved mood and decreased anxiety. This is the first study to show that a behavioral intervention (i.e., yoga) is associated with a positive correlation between changes in thalamic GABA levels and improvements in mood and anxiety. The use of METs controlled for metabolic demands of each intervention and allowed the activity level of the 2 groups (outside of the intervention) to be compared. The significantly greater level of physical activity outside the intervention in the walking group compared to the yoga group was not expected. The higher level of outside activity in the walking group could have contributed to the finding of smaller changes in mood and anxiety in the walking group, as the intervention may not have been a great enough physical challenge given the greater level of outside activity. The small sample size in the yoga group where only a nearly significant increase in thalamic GABA levels was detected was a limitation, which was offset by the findings of significant correlations between GABA levels and mood and anxiety scores. In our previous study, the acute increase in whole-slab GABA levels in experienced yoga practitioners was 27% (published) and a 26% increase in thalamic GABA levels (unpublished), compared to a 13% thalamic increase seen in the current study of yoga-naı¨ve subjects who were trained for 12 weeks. This suggests that while subjects can be trained to practice yoga in a relatively short time with a measurable effect, the associated change in GABA levels may increase with experience.

The effect of the yoga intervention on GABA levels may be due to the ability of yoga practices to increase parasympathetic nervous system (PNS) activity. In a study comparing Iyengar yoga to a walking control, the Iyengar yoga group showed greater increases in PNS activity. Yoga techniques and vagal nerve stimulation (VNS) increase PNS tone by stimulating vagal afferents. Studies suggest that the antiepileptic effects of VNS are largely mediated by widespread release of GABA. Accordingly, the practice of yoga through stimulation of vagal afferents may result in the increase of brain GABA levels as seen in the yoga group. Conclusions The 12-week yoga intervention was associated with greater improvements in mood and anxiety than a metabolically matched walking exercise. This is the first study to demonstrate that increased thalamic GABA levels are associated improved mood and decreased anxiety. It is also the first time that yoga postures have been associated with a positive correlation between acute increases in thalamic GABA levels and improvements in mean scores on mood and anxiety scales. Given that pharmacologic agents that increase the activity of the GABA system are prescribed to improve mood and decrease anxiety, the reported correlations are in the expected direction. The possible role of GABA in mediating the beneficial effects of yoga on mood and anxiety warrants further study.

The primary outcome variables were mood scores, anxiety scores, and thalamic GABA levels. Continuous measures were summarized by means_standard deviations; withingroup comparisons were performed using paired t-tests, while between-group comparisons were performed using two-sample t-tests. Discrete measures were summarized by raw counts for numerators and denominators, as well as the associated percentages, and were compared by Fisher’s exact test due to the limited sample size. Linear regression analysis was used to quantify the association between the primary outcome variables and potential predictor variables. In order to take into account within-subject correlations arising from repeated longitudinal measurements, generalized estimated equations (GEEs) were used to analyze within-group trends in mood and anxiety scores, as well as to perform betweengroup analyses. All hypothesis tests were two-tailed and conducted at the aј0.05 significance level. Confidence intervals were two-sided and were constructed with 95% confidence. Stata 10.0 (College Station, TX) was used for analysis.

Results
Demographics and study participation
Thirty-four subjects completed the study: 19 in the yoga group and 15 in the walking group. There was no significant difference between groups for demographic or descriptive variables except for height, which although statistically significant due to a relatively small standard deviation was clinically not significant. There was no difference in demographics between study completers and dropouts, with dropouts equally divided between interventions. The means for the weekly PAR METs during the 12-week intervention showed the walking group to have a significantly greater level of activity outside the intervention than the yoga group ( pј0.02); however, there was no difference between groups in activity levels on the week before Imaging Session II. Out of 36 sessions, each group attended about two thirds, with the yoga group reporting about one session a week at home.

Analysis of mood and anxiety scales and GABA levels The following analyses were done with statistically significant findings reported in the tables: (1) a GEE model for changes in mood and anxiety scores for each group at weeks 0, 4, 8, and 12; (2) tonic changes in GABA levels were assessed over the course of the intervention by subtracting Scan 1 from Scan 2 values, while acute changes associated with the intrascan session were assessed by subtracting Scan 2 from Scan 3 values; (3) tonic and acute changes in GABA levels; (4) correlations of mood and anxiety scores with GABA levels for each scan; (5) correlations of tonic (Scan 2–1) and acute (Scan 3–2) changes in mood and anxiety scores with tonic and acute changes in GABA levels. In the three ‘‘positive’’ subscales of EIFI (Positive Engagement, Revitalization, and Tranquility), an increase in score indicates improved mood. In the two ‘‘negative’’ scales, the STAI-State and EIFI-Physical Exhaustion, an increase in score indicates increased anxiety and physical exhaustion, respectively. Inverse associations (-beta), with the negative scales, indicate decreased anxiety in the within-group analysis and greater decrease in anxiety for the yoga group in the between-group analysis.

Certified Iyengar yoga instructors taught the yoga interventions, which were monitored by the Principal Investigator to ensure consistency in presentation of weekly posture sequences. Written lists of the weekly sequences and pictures of the postures were given to the subjects. After 4 weeks of instruction, subjects were encouraged to practice at home. The intrascan yoga sequence was taught in class and monitored by research staff during Imaging Session II. The structure of the walking intervention was designed to be similar to that of the yoga intervention, with weekly group sessions in which subjects walked around the gym perimeter at 2.5mph for 60 minutes. The intrascan walking session was done on a treadmill set to 2.5mph with 0 incline. This design controlled for group effects and interaction time with research staff.

Imaging Subjects were scanned on a 4-Tesla full-body MR scanner (Varian/UnityInova, Varian Inc., Palo Alto, CA) at Mclean Hospital in Belmont, MA. Scout images confirmed optimal positioning. After global shimming on unsuppressed water, T1-weighted anatomical images were taken in sagittal and axial planes [echo time (TE)/repetition time (TR)ј6.2 seconds/ 11.4 milliseconds, field-of-viewј22_22_8 cm(sagittal) and 22_22_16cm (axial), readout durationј4ms, receive bandwidthј_32 kHz, in-plane matrix sizeј128_256_16 (sagittal) and 256_256_64 (axial), in-plane resolutionј 0.94_1.9mm (sagittal) and 0.94_0.94mm (axial), readout pointsј512, slice-thicknessј2.5mm, flip-angleј118]. In our previous study, a post-hoc regional analysis that used multivoxel spectroscopic imaging showed that the greatest increase in GABA levels after the yoga intervention was in the thalamus.8 The selection of the left thalamus was based on evidence that the left side has greater parasympathetic innervations and that GABA levels are lower in the left thalamus in post-traumatic stress disorder subjects. For this study, an algorithm was developed to position a 2_2_3- cm voxel over the left thalamus. Proton spectroscopy implemented a MEGAPRESS [MEscher-GArwood Point- Resolved Echo Spectroscopy Sequence] difference-editing sequence specifically tuned for GABA.24 Manual voxel shimming yielded global water-line widths ranging from 8 to 15Hz. The MEGAPRESS sequence collected 68-millisecond echo-time spectra in an interleaved fashion where the GABA editing pulse was applied on every second transient. Additional MEGAPRESS acquisition parameters were: TRј2 seconds, spectral-bandwidthј2 kHz, readout-durationј512 milliseconds, Number of Excitations (NEX)ј384, and total scan durationј13 minutes.

In order to quantify GABA, the difference-edited spectra were processed and then fitted with LCModel using basis sets acquired at 4 T. A separate LCModel template was used to fit the unedited 68-milisecond subspectrum to obtain creatine (Cr). All fitted metabolite areas were normalized to the fitted Cr resonance from the 68-millisecond subspectrum. One (1) spectrum from the MEGAPRESS acquisition in the thalamus was excluded from analysis due to low signal-to-noise. GABA/Cr ratios are referred to as GABA levels. In order to ascertain the gray and white matter contribution to each voxel, the axial T1-weighted images were segmented into gray matter, white matter, and cerebrospinal fluid compartments using the commercial software package FSL 4.1 (FMRIB Software Library; Analysis Group, FMRIB; Oxford, UK).

There is a large body of research on the beneficial effects of exercise on depression and anxiety. The results of exercise as a treatment for mild to moderate depression compare favorably to psychotherapy and pharmacologic treatment, supporting the contention that a behavioral intervention can have an effect similar to a pharmacologic intervention on mood.

This study extends the findings of self-reported mood changes by exploring a possible mechanism: changes in thalamic GABA levels measured on MRS. This study was designed to correlate changes in mood, anxiety, and brain GABA levels, and to determine whether such changes are specific to a practice of yoga postures or whether they occur in a metabolically matched walking intervention. We hypothesize that improvement in mood scores correlate positively with GABA levels, while anxiety scores will correlate negatively with GABA levels.

Materials and Methods Subjects were recruited from the community by newspaper ads, flyers, and the Internet. Screening interviews and written informed consent were obtained at Boston University School of Medicine General Clinical Research Unit. Eligible subjects were randomized in permuted blocks (nј4) to a 12- week intervention of either Iyengar yoga or walking for three 60-minute sessions per week, with a maximum of 36 sessions. All subjects had three MRS scans: Scan 1 at baseline; Scan 2 after their 12-week intervention; immediately after Scan 2, all subjects completed a 60-minute yoga or walking intervention, depending on group assignment, which was immediately followed by Scan 3. Participants were 18–45 years old with no current Axis I diagnosis. Nonpsychoactive medications were allowed if the subject had been on a stable dose for at least 1 month with no anticipated changes during the study. The following items were exclusionary: any yoga practice in the previous 3 months, or a lifetime history of one yoga session/week for _4 weeks; current participation in psychotherapy, prayer groups, or any mind–body disciplines; a neurological disorder or medical condition that would compromise subject safety or scan data; treatment within the previous 3 months with medications that might affect the GABA system; use of tobacco products (known to affect GABA levels); alcohol consumption >4 drinks/day; and contraindication to magnetic resonance evaluation.

The following instruments were used for screening: the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders IV to identify Axis I Disorders and the Time Line Follow Back to assess alcohol consumption. Two (2) reliable and valid psychologic scales were selected to monitor the effects of the interventions on mood and anxiety over time. Mood was assessed with the Exercise- Induced Feeling Inventory (EIFI), which has four subscales: Positive Engagement, Revitalization, Tranquility, and Physical Exhaustion.16 Anxiety was assessed with the State scale of the Spielberger State–Trait Anxiety Inventory (STAI). The EIFI and STAI-State were given before each scan, prior to the first intervention session (week 0), and after completion of sessions at weeks 4, 8, and 12. Metabolic equivalents (METs) are used to rate and compare the physical demands of various activities.18 The American College of Sports Medicine list of metabolic equivalents was consulted to match the 60-minute Iyengar yoga intervention with a 60-minute walking intervention at 2.5 miles per hour (mph) on a flat surface rated at 3.0 METs. During the intervention, the Physical Activity Recall (PAR), a valid and widely used instrument, was used to convert each subject’s weekly physical activity outside of the intervention into a METs score.19,20 For each group, the mean weekly PAR METs scores was computed.

Objectives: Yoga and exercise have beneficial effects on mood and anxiety. g-Aminobutyric acid (GABA)-ergic activity is reduced in mood and anxiety disorders. The practice of yoga postures is associated with increased brain GABA levels. This study addresses the question of whether changes in mood, anxiety, and GABA levels are specific to yoga or related to physical activity.

Methods: Healthy subjects with no significant medical/psychiatric disorders were randomized to yoga or a metabolically matched walking intervention for 60 minutes 3 times a week for 12 weeks. Mood and anxiety scales were taken at weeks 0, 4, 8, 12, and before each magnetic resonance spectroscopy scan. Scan 1 was at baseline. Scan 2, obtained after the 12-week intervention, was followed by a 60-minute yoga or walking intervention, which was immediately followed by Scan 3.

Results: The yoga subjects (nј19) reported greater improvement in mood and greater decreases in anxiety than the walking group (nј15). There were positive correlations between improved mood and decreased anxiety and thalamic GABA levels. The yoga group had positive correlations between changes in mood scales and changes in GABA levels.

Conclusions: The 12-week yoga intervention was associated with greater improvements in mood and anxiety than a metabolically matched walking exercise. This is the first study to demonstrate that increased thalamic GABA levels are associated with improved mood and decreased anxiety. It is also the first time that a behavioral intervention (i.e., yoga postures) has been associated with a positive correlation between acute increases in thalamic GABA levels and improvements in mood and anxiety scales. Given that pharmacologic agents that increase the activity of the GABA system are prescribed to improve mood and decrease anxiety, the reported correlations are in the expected direction. The possible role of GABA in mediating the beneficial effects of yoga on mood and anxiety warrants further study.

Introduction
Yoga has been used to reduce symptoms of depression, anxiety, and epilepsy. Reduced activity ing-aminobutyric acid (GABA) systems has been found in mood disorders, anxiety disorders, and epilepsy. All three ofthese conditions respond to pharmacologic agents known to increase GABA system activity, raising the possibility that some of the therapeutic effect may be via increased GABA activity. In a previous study using magnetic resonance spectroscopy (MRS) to obtain brain GABA levels, our group demonstrated that experienced yoga practitioners had a significant (27%) increase in whole-slab GABA levels after a 60- minute session of yoga postures compared to no change in GABA levels in controls after a 60-minute reading session. These findings raise the question of whether the associated increase in GABA levels was specific to yoga or related to physical activity in general.