No abstract

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.

No abstract

Treatment dropout is a problem of great prevalence and stands as an obstacle to recovery in cocaine-dependent (CD) individuals. Treatment attrition in CD individuals may result from impairments in cognitive control, which can be reliably measured by the Stroop color-word interference task. The present analyses contrasted baseline performance on the color-naming, word-reading, and interference subtests of the Stroop task in CD subjects who completed a cocaine treatment trial (completers: N ¼ 50) and those who dropped out of the trial before completion (non-completers: N ¼ 24). A logistic regression analysis was used to predict trial completion using three models with the following variables: the Stroop task subscale scores (Stroop model); the Hamilton depression rating scale (HDRS) scores (HDRS model); and both the Stroop task subscale scores and HDRS scores (Stroop and HDRS model). Each model was able to significantly predict group membership (completers vs non-completers) better than a model based on a simple constant (HDRS model p ¼ 0.02, Stroop model p ¼ 0.006, and Stroop and HDRS model p ¼ 0.003). Models using the Stroop preformed better than the HDRS model. These findings suggest that the Stroop task can be used to identify cocaine-dependent subjects at risk for treatment dropout. The Stroop task is a widely available, reliable, and valid instrument that can be easily employed to identify and tailor interventions of at risk individuals in the hope of improving treatment compliance.

Objectives: The aim of this study was to compare changes in brain ␥-aminobutyric (GABA) levels associated with an acute yoga session versus a reading session. It was hypothesized that an individual yoga session would be associated with an increase in brain GABA levels. Design: This is a parallel-groups design. Settings/location: Screenings, scan acquisitions, and interventions took place at medical school-affiliated centers. Subjects: The sample comprised 8 yoga practitioners and 11 comparison subjects. Interventions: Yoga practitioners completed a 60-minute yoga session and comparison subjects completed a 60-minute reading session. Outcome measures: GABA-to-creatine ratios were measured in a 2-cm axial slab using magnetic resonance spectroscopic imaging immediately prior to and immediately after interventions. Results: There was a 27% increase in GABA levels in the yoga practitioner group after the yoga session (0.20 mmol/kg) but no change in the comparison subject group after the reading session (Ϫ0.001 mmol/kg) (t ϭ Ϫ2.99, df ϭ 7.87, p ϭ 0.018). Conclusions: These findings demonstrate that in experienced yoga practitioners, brain GABA levels increase after a session of yoga. This suggests that the practice of yoga should be explored as a treatment for disorders with low GABA levels such as depression and anxiety disorders. Future studies should compare yoga to other forms of exercise to help determine whether yoga or exercise alone can alter GABA levels.

This study was conducted to explore differences in gray and white matter volume between cocaine-dependent and healthy comparison subjects using optimized voxel-based morphometry (VBM). Brain magnetic resonance imaging (MRI) and neuropsychological function tests were performed for 40 cocaine-dependent subjects (41.476.9 years, 27 men) and 41 healthy age-and sex-matched comparison subjects (38.778.8 years, 26 men). Optimally normalized whole brain MR images were segmented, modulated, smoothed, and compared between groups with statistical parametric mapping. The cocaine-dependent group had lower gray matter volumes in bilateral premotor cortex (Brodmann area (BA) 6, 8; 16.6%), right orbitofrontal cortex (BA 10, 15.1%), bilateral temporal cortex (BA 20, 38; 15.9%), left thalamus (12.6%), and bilateral cerebellum (13.4%) as well as lower right cerebellar white matter volume (10.0%) relative to the comparison group at a corrected po0.05 for multiple comparisons. Duration of cocaine use negatively correlated with right and left cerebellar gray matter volumes (r ¼ À0.37, r ¼ À0.39, respectively). In cocaine-dependent subjects, lower cerebellar hemispheric gray and white matter volumes were correlated with deficits in executive function and decreased motor performance. This study reports that cocaine-dependent subjects have lower gray matter volumes in cerebellar hemispheres as well as in frontal, temporal cortex, and thalamus. These findings are the first to suggest that the cerebellum may be vulnerable to cocaine-associated brain volume changes, and that cerebellar deficits may contribute to neuropsychological deficits and motor dysfunction frequently observed in cocaine-dependent subjects.

The use of deception threatens both participant safety and the integrity of research findings. Deception may be fueled in part by undue inducements, overly restrictive criteria for entry, and increased demand for healthy controls. Screening measures designed to detect deception among study subjects would aid in both protecting subjects and ensuring the quality of research findings.

No abstract