Less activation in the left dorsolateral prefrontal cortex in the reanalysis of the response to a meal in obese than in lean women and its association with successful weight loss.
BACKGROUND
We previously found that obese men have less activation in the left dorsolateral prefrontal cortex (LDLPFC) in response to a meal than do lean men, which indicates an association between this altered neuronal response and the pathophysiology of obesity.


OBJECTIVE
The objectives of the study were to extend this finding in obese women and to investigate activity in this region in women with a history of severe obesity who have successfully lost weight (ie, formerly obese women, sometimes called postobese women).


METHODS
We reanalyzed previously collected data to compare postmeal (after receiving a liquid meal) with premeal (after a 36-h fast) regional cerebral blood flow, a marker of neuronal activity, by using (15)O-water positron emission tomography in 10 lean [26 +/- 6% body fat (BF)], 9 obese (39 +/- 3%BF) and 8 formerly obese (28 +/- 4%BF) right-handed women. Data were analyzed by using a 2-level, random-effect analysis of variance.


RESULTS
The regional cerebral blood flow in the LDLPFC differed in response to the meal across the 3 groups (P < 0.001, uncorrected for multiple comparisons). Post hoc group comparisons showed that obese women had significantly less activation in this area than did lean and formerly obese women. No significant difference between formerly obese and lean women was found.


CONCLUSIONS
These results extend our previous findings, indicating that obese women have less activation in the LDLPFC in response to a meal than do lean or formerly obese women. Neuronal activity in this region did not differ significantly between the latter 2 groups. Longitudinal studies are needed to determine whether these differences in neuronal activity change with or predict weight change.
Le
Duc Son Nt
DS
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology & Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health, Phoenix, AZ 85016, USA. leds@mail.nih.gov
Pannacciulli
Nicola
N
Chen
Kewei
K
Salbe
Arline D
AD
Del Parigi
Angelo
A
Hill
James O
JO
Wing
Rena R
RR
Reiman
Eric M
EM
Krakoff
Jonathan
J
D000328:Adult; D000704:Analysis of Variance; D001069:Appetite Regulation; D002560:Cerebrovascular Circulation; D004435:Eating; D005215:Fasting / Q000502:physiology*; D005260:Female; D006801:Humans; D009765:Obesity / Q000000981:diagnostic imaging / Q000503:physiopathology*; D049268:Positron-Emission Tomography / Q000379:methods; D019518:Postprandial Period; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D012528:Satiety Response; D013851:Thinness / Q000000981:diagnostic imaging / Q000503:physiopathology; D015431:Weight Loss