Article

Brain Structural Correlates of Reward Sensitivity and Impulsivity in Adolescents with Normal and Excess Weight

Department of Personality, Evaluation and Psychological Treatment, University of Granada, Granada, Spain.
PLoS ONE (Impact Factor: 3.23). 11/2012; 7(11):e49185. DOI: 10.1371/journal.pone.0049185
Source: PubMed

ABSTRACT

Neuroscience evidence suggests that adolescent obesity is linked to brain dysfunctions associated with enhanced reward and somatosensory processing and reduced impulse control during food processing. Comparatively less is known about the role of more stable brain structural measures and their link to personality traits and neuropsychological factors on the presentation of adolescent obesity. Here we aimed to investigate regional brain anatomy in adolescents with excess weight vs. lean controls. We also aimed to contrast the associations between brain structure and personality and cognitive measures in both groups.
Fifty-two adolescents (16 with normal weight and 36 with excess weight) were scanned using magnetic resonance imaging and completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the UPPS-P scale, and the Stroop task. Voxel-based morphometry (VBM) was used to assess possible between-group differences in regional gray matter (GM) and to measure the putative differences in the way reward and punishment sensitivity, impulsivity and inhibitory control relate to regional GM volumes, which were analyzed using both region of interest (ROI) and whole brain analyses. The ROIs included areas involved in reward/somatosensory processing (striatum, somatosensory cortices) and motivation/impulse control (hippocampus, prefrontal cortex).
Excess weight adolescents showed increased GM volume in the right hippocampus. Voxel-wise volumes of the second somatosensory cortex (SII) were correlated with reward sensitivity and positive urgency in lean controls, but this association was missed in excess weight adolescents. Moreover, Stroop performance correlated with dorsolateral prefrontal cortex volumes in controls but not in excess weight adolescents.
Adolescents with excess weight have structural abnormalities in brain regions associated with somatosensory processing and motivation.

Download full-text

Full-text

Available from: Laura Moreno-López
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A psychobiological dimension of eating behaviour is proposed, which is anchored at the low end by energy intake that is relatively well matched to energy output and is reflected by a stable body mass index (BMI) in the healthy range. Further along the continuum are increasing degrees of overeating (and BMI) characterized by more severe and more compulsive ingestive behaviours. In light of the many similarities between chronic binge eating and drug abuse, several authorities have adopted the perspective that an apparent dependence on highly palatable food-accompanied by emotional and social distress-can be best conceptualized as an addiction disorder. Therefore, this review also considers the overlapping symptoms and characteristics of binge eating disorder (BED) and models of food addiction, both in preclinical animal studies and in human research. It also presents this work in the context of the modern and "toxic" food environment and therein the ubiquitous triggers for over-consumption. We complete the review by providing evidence that what we have come to call "food addiction" may simply be a more acute and pathologically dense form of BED.
    Full-text · Article · May 2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Obsessive-compulsive disorder (OCD) is a clinically heterogeneous condition. Although structural brain alterations have been consistently reported in OCD, their interaction with particular clinical subtypes deserves further examination. Among other approaches, a two-group classification in patients with autogenous and reactive obsessions has been proposed. The purpose of the present study was to assess, by means of a voxel-based morphometry analysis, the putative brain structural correlates of this classification scheme in OCD patients. Ninety-five OCD patients and 95 healthy controls were recruited. Patients were divided into autogenous (n = 30) and reactive (n = 65) sub-groups. A structural magnetic resonance image was acquired for each participant and pre-processed with SPM8 software to obtain a volume-modulated gray matter map. Whole-brain and voxel-wise comparisons between the study groups were then performed. In comparison to the autogenous group, reactive patients showed larger gray matter volumes in the right Rolandic operculum. When compared to healthy controls, reactive patients showed larger volumes in the putamen (bilaterally), while autogenous patients showed a smaller left anterior temporal lobe. Also in comparison to healthy controls, the right middle temporal gyrus was smaller in both patient subgroups. Our results suggest that autogenous and reactive obsessions depend on partially dissimilar neural substrates. Our findings provide some neurobiological support for this classification scheme and contribute to unraveling the neurobiological basis of clinical heterogeneity in OCD.
    Full-text · Article · Sep 2013 · PLoS ONE
  • [Show abstract] [Hide abstract]
    ABSTRACT: Individual differences on reward sensitivity and impulsivity are associated with the risk of obesity, and unhealthy diets and adiposity can ultimately impair reward processing and cognitive control. Here I review findings from personality, neuropsychological and neuroimaging measures of reward processing and impulse control in pediatric and adult populations with excess weight. Personality measures reflect general dispositional traits of these populations, including sensitivity to reward and punishment, and cognitive and emotional facets of impulsivity. Neuropsychological measures assess the current function of specific cognitive processes relevant to reward and impulse control, including attention/motivation toward food vs. non-food stimuli, response (dis)inhibition and decision-making (e.g. preference for immediate rewards or disregard of potential outcomes). Neuroimaging measures are utilized to unveil the neural underpinnings of these traits and processes. Findings suggest that both young and adult populations with obesity are characterized by dispositionally lower sensitivity to reward (reward deficiency), coupled with higher responsivity to food rewards, poorer response inhibition and steeper discounting of delayed rewards, all of which are longitudinally associated with weight gain. These deficits are manifested in somatosensory (insula/frontal operculum), reward seeking (striatum, extended amygdala, cerebellum), stimulus-oriented attention (dorsolateral prefrontal cortex), and decision-making (orbitofrontal cortex) brain systems dysfunction. © 2014 Springer Science+Business Media New York. All rights are reserved.
    No preview · Chapter · May 2014
Show more