Reanalysis of the Obesity-Related Attenuation in the Left Dorsolateral Prefrontal Cortex Response to a Satiating Meal Using Gyral Regions-of-Interest

• Published in: Journal of the American College of Nutrition Vol. 28; no. 6; pp. 667 - 673
• Main Authors: Le, Duc Son Nguyen Trung, Chen, Kewei, Pannacciulli, Nicola, Gluck, Marci, Reiman, Eric M, Krakoff, Jonathan
• Format: Journal Article
• Language: English
• Published: United States American College of Nutrition 01.12.2009
• Subjects: Blood Glucose - metabolism; Body Composition - physiology; Brain Mapping; cerebral cortex; Cerebrovascular Circulation - physiology; Female; gyral regions; Humans; Hunger - physiology; Image Processing, Computer-Assisted; Insulin - blood; left dorsolateral prefrontal cortex; Magnetic Resonance Imaging; Male; meals (menu); men; Neurons - diagnostic imaging; Neurons - metabolism; nutrition physiology; obesity; Obesity - diagnostic imaging; Obesity - metabolism; Obesity - physiopathology; physiological response; Postprandial Period - physiology; Prefrontal Cortex - diagnostic imaging; Prefrontal Cortex - metabolism; Prefrontal Cortex - physiopathology; Radioimmunoassay; Radionuclide Imaging; Satiation - physiology; satiety; women
• ISSN: 0731-5724; 1541-1087
• DOI: 10.1080/07315724.2009.10719799

OBJECTIVE: The left dorsolateral prefrontal cortex (LDLPFC), which includes the inferior (IFG), middle (MFG), and superior (SFG) frontal gyri, has been implicated in satiation. Using a voxel-based approach, we previously identified an LDLPFC region (as reported as peak voxel) in which a reduced neuronal response to a meal was associated with obesity. In this study, we sought to determine which gyri in the LDLPFC best distinguished the neuronal responses to a meal using a different statistical approach. METHODS: We reanalyzed brain responses to a meal using the hypothesis-driven region-of-interest-based (ROI) approach. Regional cerebral blood flow (rCBF), a marker of neuronal activity in the LDLPFC and its 3 gyri, was acquired in 2 conditions (hunger and after the satiating meal) using ¹⁵O-water positron emission tomography scans. rCBF was extracted and estimated using masks of the 3 gyri that were created in MRIcro and Statistical Parametric Mapping 5 software. RESULTS: Using the ROI approach, a satiation-related reduction in LDLPFC rCBF was observed in the obese (p = 0.04) and tended to be significantly greater than that in lean subjects (p = 0.07). The rCBF reduction was greater in the obese subjects than in the lean subjects in the left IFG (p = 0.03) and MFG (p = 0.004) after adjustment was made for age, sex, and number of voxels in these gyri, but not in the SFG (p = 0.5). CONCLUSIONS: Our results are consistent with those obtained by the voxel-based approach in showing the association between obesity and a satiation-related reduction in LDLPFC activity. This LDLPFC response preferentially involves the IFG and MFG. We suggest that these brain regions could be targeted by new therapeutic interventions.