BACKGROUND. Bariatric surgeries are the most effective treatments for successful and sustained weight loss, but individuals vary in treatment response. Understanding the neurobiological and behavioral mechanisms accounting for this variation could lead to the development of personalized therapeutic approaches and improve treatment outcomes. The primary objectives of this study were to investigate changes in taste preferences and taste-induced brain responses after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) and to identify potential taste-related predictors of weight loss. METHODS.Females, ages 18 to 55, with a body mass index greater than or equal to 35 kg/m 2 , and approved for bariatric surgery at the Johns Hopkins Center for Bariatric Surgery were recruited for participation. Demographics, anthropometrics, liking ratings, and neural responses to varying concentrations of sucrose plus fat mixtures were assessed before and after surgery via visual analog scales and functional MRI. RESULTS.Bariatric surgery produced decreases in liking for sucrose-sweetened mixtures. Greater preference for sucrosesweetened mixtures before surgery was associated with greater weight loss in RYGB, but not VSG. In the RYGB group only, individuals who showed lower taste-induced activation in the ventral tegmental area (VTA) before surgery and greater changes in taste-induced VTA activation 2 weeks following surgery experienced increased weight loss. CONCLUSION.The anatomical and/or metabolic changes associated with RYGB may more effectively "reset" the neural processing of reward stimuli, thereby rescuing the blunted activation in the mesolimbic pathway found in patients with obesity. Further, these findings suggest that RYGB may be particularly effective in patients with a preference for sweet foods.

BACKGROUND AND PURPOSE: Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the human brain and is implicated in several neuropathologies. Glutathione is a major antioxidant in the brain and is considered a marker of oxidative stress. Several studies have reported age-related declines in GABA levels in adulthood, but the trajectory of both GABA and glutathione during childhood has not been well explored. The aim of this study is to establish how GABA and glutathione vary with age during early development.MATERIALS AND METHODS: Twenty-three healthy children (5.6-13.9 years of age) were recruited for this study. MR imaging/MR spectroscopy experiments were conducted on a 3T MR scanner. A 27-mL MR spectroscopy voxel was positioned in the frontal lobe. J-difference edited MR spectroscopy was used to spectrally edit GABA and glutathione. Data were analyzed using the Gannet software, and GABAþ (GABA þ macromolecules/homocarnosine) and glutathione were quantified using water (GABAþ H2O and Glutathione H2O ) and Cr (GABAþ/Cr and glutathione/Cr) as concentration references. Also, the relative gray matter contribution to the voxel volume (GM ratio ) was estimated from structural images. Pearson correlation coefficients were used to examine the association between age and GABAþ H2O (and glutathione H2O ), between age and GABAþ/Cr (and glutathione/Cr), and between age and GM ratio .RESULTS: Both GABAþ H2O (r ¼ 0.63, P ¼ .002) and GABAþ/Cr (r ¼ 0.48, P ¼ .026) significantly correlated with age, whereas glutathione measurements and GM ratio did not. CONCLUSIONS:We demonstrate increases in GABA and no differences in glutathione with age in a healthy pediatric sample. This study provides insight into neuronal maturation in children and may facilitate better understanding of normative behavioral development and the pathophysiology of developmental disorders. ABBREVIATIONS: f GM ¼ gray matter voxel tissue fraction; f WM ¼ white matter voxel tissue fraction; GABA ¼ gamma-aminobutyric acid; GSH ¼ glutathione; HERMES ¼ Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy; MEGA-PRESS ¼ MEscher-GArwood point-resolved spectroscopy sequence; i.u. ¼ institutional units; GM ratio ¼ relative GM contribution to voxel volume; GABAþ ¼ GABA with macromolecules/homocarnosine

Objective Obesity risk transmits from parents to children. Underlying neural mechanisms were investigated in this study by evaluating influences of familial obesity risk defined by maternal obesity and influences of current overweight on three indices of brain structure in adolescents. Methods In total, 22 lean adolescents with lean mothers (lean low‐risk), 25 lean adolescents with mothers with obesity/overweight (lean high‐risk), and 36 adolescents with obesity/overweight underwent structural MRI scans for estimation of regional gray and white matter volume and cortical thickness. Results The lean high‐risk compared with the lean low‐risk group demonstrated lower gray and white matter volume and cortical thickness in the postcentral gyrus (somatosensory cortex), lower gray and white matter volume in the opercular cortex (taste cortex), lower gray matter volume and cortical thickness in the anterior cingulate cortex, and lower cortical thickness in the precuneus. Comparisons of the lean and obesity/overweight groups revealed further structural alterations in the postcentral gyrus, posterior cingulate gyrus, and middle temporal gyrus. Conclusions Familial obesity risk and current obesity/overweight were associated with overlapping and distinct patterns of brain structure alterations. Longitudinal studies are warranted to investigate whether structural changes associated with familial obesity risk predict future weight trajectories.