SAT-LB59 Functional MRI Study: Weight Loss Induced Changes in Taste Receipt-Induced Activation in the Striatum and Hypothalamus

Abstract

Background: Reward behaviors including those related to eating are influenced by output from the ventral striatum (VS), dorsal striatal [caudate(Cau) and putamen(Put)]and hypothalamus (HTH). We hypothesized that weight loss would induce modifications in activation in these regions of interest (ROI) during a consummatory reward task. Methods: We recruited metabolic abnormal obese (MAO) from the VA St.Louis Health Care System and Washington University in St.Louis (WUSTL). MAO was screened for by fasting insulin and plasma glucose, 2 hour 75 gram OGTT, and hemoglobin A1c. MAO was defined as prediabetes by ADA criteria and/ or elevated HOMA-IR. Functional magnetic resonance imaging (fMRI) scanning sessions were completed at the WUSTL Center for Clinical Imaging Research. A rapid event-related design was used to randomly deliver taste of chocolate milk (choc) or tasteless water (wat). Each taste receipt was proceeded by a cue of corresponding image of chocolate milk or a glass of water. A total of 5 runs, each with 24 trials were completed. Imaging analyses included preprocessing with fMRIprep including censoring excessive motion ≥ 0.5mm. Single subject GLM analyses were completed in AFNI. ROIs were designated bilaterally (lt and rt) except for HTH. A canonical HRF was applied to the food cue event and the AFNI tent function over 9 TRs was applied to the taste receipt event. To evaluate for an effect of weight loss (WL) on food cue and taste receipt-induced activation, repeated measures ANOVA for each region was completed with condition (choc or wat) as a covariate. Also in the model for taste receipt, repetition time (TR) was included as a covariate. Results reported as F(sign.). Results: Ten participants achieved at least 7% WL, (range 7-15%), 44±8 years, BMI 38±4kg/m2, f/m 4/6, fasting pg 105±11, 2 hour OGTT pg 132 ±49 mg/dL, HOMA-IR 3.9±1.8. One participant fulfilled criteria for T2D. For taste receipt several significant effects were found for WL: Cau_lt WL 5.9(0.02) and WL*TR 4.9(0.03), Cau_rt WL 8.6(0.004) and WL*TR 8(0.005), Put_lt WL 8.5(0.004), HTH WL*condition 5.4(0.02) and a trend for WL 3.3(0.07). All other comparisons were non-significant including all in the VS and all for food cue. Conclusions: Moderate weight loss in MAO modified taste receipt-induced activation in the Cau, Put, and HTH but not in the VS.