Reanalysis of the obesity-related attenuation in the left dorsolateral prefrontal cortex response to a satiating meal using gyral regions-of-interest.
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 (15)O-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.
Le
Duc Son Nguyen Trung
DS
Obesity and Diabetes Clinical Research Section, NIDDK-NIH, DHHS, Phoenix, Arizona 85016, USA. ducsonmd@gmail.com
Chen
Kewei
K
Pannacciulli
Nicola
N
Gluck
Marci
M
Reiman
Eric M
EM
Krakoff
Jonathan
J
D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D006815:Hunger / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D007328:Insulin / Q000097:blood; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000000981:diagnostic imaging / Q000378:metabolism*; D009765:Obesity / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D019518:Postprandial Period / Q000502:physiology; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D011863:Radioimmunoassay; D011877:Radionuclide Imaging; D012527:Satiation / Q000502:physiology*
D001786:Blood Glucose; D007328:Insulin