Ventral frontal satiation-mediated responses to food aromas in obese and normal-weight women.
BACKGROUND
Sensory properties of foods promote and guide consumption in hunger states, whereas satiation should dampen the sensory activation of ingestive behaviors. Such activation may be disordered in obese individuals.


OBJECTIVE
Using functional magnetic resonance imaging (fMRI), we studied regional brain responses to food odor stimulation in the sated state in obese and normal-weight individuals targeting ventral frontal regions known to be involved in coding for stimulus reward value.


METHODS
Forty-eight women (25 normal weight; 23 obese) participated in a 2-day (fed compared with fasting) fMRI study while smelling odors of 2 foods and an inedible, nonfood object. Analyses were conducted to permit an examination of both general and sensory-specific satiation (satiation effects specific to a given food).


RESULTS
Normal-weight subjects showed significant blood oxygen level-dependent responses in the ventromedial prefrontal cortex (vmPFC) to food aromas compared with responses induced by the odor of an inedible object. Normal-weight subjects also showed general (but not sensory-specific) satiation effects in both the vmPFC and orbitofrontal cortex. Obese subjects showed no differential response to the aromas of food and the inedible object when fasting. Within- and between-group differences in satiation were driven largely by changes in the response to the odor of the inedible stimulus. Responses to food aromas in the obese correlated with trait negative urgency, the tendency toward negative affect-provoked impulsivity.


CONCLUSIONS
Ventral frontal signaling of reward value may be disordered in obesity, with negative urgency heightening responses to food aromas. The observed nature of responses to food and nonfood stimuli suggests that future research should independently quantify each to fully understand brain reward signaling in obesity.
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
William J A
WJ
Eiler
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
Mario
M
Dzemidzic
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
K Rose
KR
Case
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
Cheryl L H
CL
Armstrong
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
Richard D
RD
Mattes
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
Melissa A
MA
Cyders
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
Robert V
RV
Considine
From the Departments of Neurology (WJAE, MD, KRC, and DAK), Radiology (MD and DAK), Medicine (RVC) (Endocrinology), and Psychiatry (DAK), Indiana University School of Medicine, Indianapolis, IN; the Department of Nutrition Science, Purdue University, West Lafayette, IN (CLHA and RDM); and the Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN (MAC).
David A
DA
Kareken
D000328:Adult; D015992:Body Mass Index; D062408:Breakfast; D005215:Fasting; D005247:Feeding Behavior; D005260:Female; D005502:Food; D006801:Humans; D021621:Imaging, Three-Dimensional; D007175:Impulsive Behavior; D007196:Indiana; D008279:Magnetic Resonance Imaging; D009765:Obesity / Q000378:metabolism*; D009812:Odorants; D010556:Personality Tests; D019518:Postprandial Period; D017397:Prefrontal Cortex / Q000378:metabolism*; D012528:Satiety Response; D011984:Sensory Receptor Cells / Q000378:metabolism*; D055815:Young Adult