Rebecca J. Lepping

Brain Responses to Food Logos in Obese and Healthy Weight Children

OBJECTIVE To evaluate brain activation in response to common food and nonfood logos in healthy weight and obese children. STUDY DESIGN Ten healthy weight children (mean body mass index in the 50th percentile) and 10 obese children (mean body mass index in the 97.9th percentile) completed self-report measures of self-control. They then underwent functional magnetic resonance imaging while viewing food and nonfood logos. RESULTS Compared with the healthy weight children, obese children showed significantly less brain activation to food logos in the bilateral middle/inferior prefrontal cortex, an area involved in cognitive control. CONCLUSION When shown food logos, obese children showed significantly less brain activation than the healthy weight children in regions associated with cognitive control. This provides initial neuroimaging evidence that obese children may be more vulnerable to the effects of food advertising.

Importance of reward and prefrontal circuitry in hunger and satiety: Prader-Willi syndrome vs simple obesity.

Background:The majority of research on obesity (OB) has focused primarily on clinical features (eating behavior, adiposity measures) or peripheral appetite-regulatory peptides (leptin, ghrelin). However, recent functional neuroimaging studies have demonstrated that some reward circuitry regions that are associated with appetite-regulatory hormones are also involved in the development and maintenance of OB. Prader–Willi syndrome (PWS), characterized by hyperphagia and hyperghrelinemia reflecting multi-system dysfunction in inhibitory and satiety mechanisms, serves as an extreme model of genetic OB. Simple (non-PWS) OB represents an OB-control state.Objective:This study investigated subcortical food motivation circuitry and prefrontal inhibitory circuitry functioning in response to food stimuli before and after eating in individuals with PWS compared with OB. We hypothesized that groups would differ in limbic regions (that is, hypothalamus, amygdala) and prefrontal regions associated with cognitive control (that is, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC) after eating.Design and participants:A total of 14 individuals with PWS, 14 BMI- and age-matched individuals with OB, and 15 age-matched healthy-weight controls viewed food and non-food images while undergoing functional MRI before (pre-meal) and after (post-meal) eating. Using SPM8, group contrasts were tested for hypothesized regions: hypothalamus, nucleus accumbens (NAc), amygdala, hippocampus, OFC, medial PFC and DLPFC.Results:Compared with OB and HWC, PWS demonstrated higher activity in reward/limbic regions (NAc, amygdala) and lower activity in the hypothalamus and hippocampus in response to food (vs non-food) images pre-meal. Post meal, PWS exhibited higher subcortical activation (hypothalamus, amygdala, hippocampus) compared with OB and HWC. OB showed significantly higher activity versus PWS and HWC in cortical regions (DLPFC, OFC) associated with inhibitory control.Conclusion:In PWS, compared with OB per se, results suggest hyperactivations in subcortical reward circuitry and hypoactivations in cortical inhibitory regions after eating, which provides evidence of neural substrates associated with variable abnormal food motivation phenotypes in PWS and simple OB.

Neural Responses to Visual Food Stimuli After a Normal vs. Higher Protein Breakfast in Breakfast-Skipping Teens: A Pilot fMRI Study

This functional magnetic resonance imaging (fMRI) pilot study identified whether breakfast consumption would alter the neural activity in brain regions associated with food motivation and reward in overweight “breakfast skipping” (BS) adolescent girls and examined whether increased protein at breakfast would lead to additional alterations. Ten girls (Age: 15 ± 1 years; BMI percentile 93 ± 1%; BS 5 ± 1×/week) completed 3 testing days. Following the BS day, the participants were provided with, in randomized order, normal protein (NP; 18 ± 1 g protein) or higher protein (HP; 50 ± 1 g protein) breakfast meals to consume at home for 6 days. On day 7 of each pattern, the participants came to the laboratory to consume their respective breakfast followed by appetite questionnaires and an fMRI brain scan to identify brain activation responses to viewing food vs. nonfood images prior to lunch. Breakfast consumption led to enduring (i.e., 3‐h post breakfast) reductions in neural activation in the hippocampus, amygdala, cingulate, and parahippocampus vs. BS. HP led to enduring reductions in insula and middle prefrontal cortex activation vs. NP. Hippocampal, amygdala, cingulate, and insular activations were correlated with appetite and inversely correlated with satiety. In summary, the addition of breakfast led to alterations in brain activation in regions previously associated with food motivation and reward with additional alterations following the higher‐protein breakfast. These data suggest that increased dietary protein at breakfast might be a beneficial strategy to reduce reward‐driven eating behavior in overweight teen girls. Due to the small sample size, caution is warranted when interpreting these preliminary findings.

Changes in brain activation to food pictures after adjustable gastric banding

BACKGROUND Adjustable gastric banding is an effective weight-loss treatment, but little is known about the neural mechanisms underlying weight loss. The purpose of the present study was to determine whether gastric banding affects brain function in regions previously implicated in food motivation, reward, and cognitive control. The setting for the study was the University of Missouri-Kansas City, Department of Psychology; Hoglund Brain Imaging Center, University of Kansas Medical Center; and private practice in the United States. METHODS Ten obese participants were recruited before adjustable gastric banding surgery (mean body mass index before surgery 40.6 ± 1.96 kg/m2). Their mean body mass index at 12 weeks after surgery was 36.1 ± 2.32 kg/m2, with a mean percentage of excess weight loss of 25.21% ± 8.41%. Functional magnetic resonance imaging scans were conducted before and 12 weeks after adjustable gastric banding surgery. At each assessment point, the participants completed questionnaires assessing food motivation and were scanned while hungry (before eating) and immediately after a standardized meal (after eating). During the functional magnetic resonance imaging scans, the participants viewed food pictures, nonfood pictures (animals), and blurred baseline control pictures. The functional magnetic resonance imaging data were analyzed using BrainVoyager QX. RESULTS After surgery, the participants reported significantly less food motivation and more cognitive restraint. The participants also showed decreased brain activation to food versus nonfood pictures in regions implicated in food motivation and reward, including the parahippocampus, medial prefrontal cortex, insula, and inferior frontal gyrus. In contrast, they demonstrated increased activation to food versus nonfood pictures in anterior prefrontal cortex, a region implicated in cognitive control and inhibition. CONCLUSION This is the first study to examine the functional brain changes after gastric banding surgery and 1 of the first studies to longitudinally examine neural changes associated with weight loss. These results have provided preliminary evidence that adjustable gastric banding alters brain function in regions known to regulate reward and cognitive control.

Branding and a child’s brain: an fMRI study of neural responses to logos

Branding and advertising have a powerful effect on both familiarity and preference for products, yet no neuroimaging studies have examined neural response to logos in children. Food advertising is particularly pervasive and effective in manipulating choices in children. The purpose of this study was to examine how healthy children’s brains respond to common food and other logos. A pilot validation study was first conducted with 32 children to select the most culturally familiar logos, and to match food and non-food logos on valence and intensity. A new sample of 17 healthy weight children were then scanned using functional magnetic resonance imaging. Food logos compared to baseline were associated with increased activation in orbitofrontal cortex and inferior prefrontal cortex. Compared to non-food logos, food logos elicited increased activation in posterior cingulate cortex. Results confirmed that food logos activate some brain regions in children known to be associated with motivation. This marks the first study in children to examine brain responses to culturally familiar logos. Considering the pervasiveness of advertising, research should further investigate how children respond at the neural level to marketing.

A comparison of functional brain changes associated with surgical versus behavioral weight loss

Few studies have examined brain changes in response to effective weight loss; none have compared different methods of weight‐loss intervention. Functional brain changes associated with a behavioral weight loss intervention to those associated with bariatric surgery were compared.

The neuroanatomy of genetic subtype differences in Prader-Willi syndrome.

Despite behavioral differences between genetic subtypes of Prader–Willi syndrome (PWS), no studies have been published characterizing brain structure in these subgroups. Our goal was to examine differences in the brain structure phenotype of common subtypes of PWS [chromosome 15q deletions and maternal uniparental disomy 15 (UPD)]. Fifteen individuals with PWS due to a typical deletion [(DEL) type I; n = 5, type II; n = 10], eight with PWS due to UPD, and 25 age‐matched healthy‐weight individuals (HWC) participated in structural magnetic resonance imaging (MRI) scans. A custom voxel‐based morphometry processing stream was used to examine regional differences in gray and white matter volume (WMV) between groups, covarying for age, sex, and body mass index (BMI). Overall, compared to HWC, PWS individuals had lower gray matter volumes (GMV) that encompassed the prefrontal, orbitofrontal and temporal cortices, hippocampus and parahippocampal gyrus, and lower WMVs in the brain stem, cerebellum, medial temporal, and frontal cortex. Compared to UPD, the DEL subtypes had lower GMV primarily in the prefrontal and temporal cortices, and lower white matter in the parietal cortex. The UPD subtype had more extensive lower gray and WMVs in the orbitofrontal and limbic cortices compared to HWC. These preliminary findings are the first structural neuroimaging findings to support potentially separate neural mechanisms mediating the behavioral differences seen in these genetic subtypes.

Resting-state brain connectivity after surgical and behavioral weight loss.

Changes in food‐cue neural reactivity associated with behavioral and surgical weight loss interventions have been reported. Resting functional connectivity represents tonic neural activity that may contribute to weight loss success. This study explores whether intervention type is associated with differences in functional connectivity after weight loss.

Tonic hyper‐connectivity of reward neurocircuitry in obese children

Obese children demonstrate less activation in prefrontal regions associated with self‐control and inhibition when presented with food cues and advertisements. This study evaluates the differences between obese and healthy weight children in resting‐state functional connectivity to these brain regions.

Cognitive Function and White Matter Changes Associated with Renal Transplantation.

Background: End-stage renal disease (ESRD) is a disease with an aging population and a high prevalence of cognitive impairment affecting quality of life, health care costs and mortality. Structural changes in the brain with decreased white matter integrity have been observed in ESRD. Understanding the changes in cognition and associated changes in brain structure after renal transplantation can help define the mechanisms underlying cognitive impairment in ESRD. Methods: We conducted a prospective, observational cohort study in ESRD patients listed for renal transplantation and followed them post-transplantation. We assessed their cognitive function with a battery of neuropsychological tests and brain white matter integrity with diffusion tensor imaging (DTI) both before transplant and 3 months after transplant. Results: Eleven patients, aged 56.5 ± 10.7 years, completed the study. Cognitive measures of memory and executive function improved after the transplant, specifically on tests of logical memory I (p = 0.004), logical memory II (p = 0.003) and digit symbol (p < 0.0001). DTI metrics also improved post the transplant with an increase in fractional anisotropy (p = 0.01) and decrease in mean diffusivity (p = 0.004). These changes were more prominent in tracts associated with memory and executive function. Conclusions: Cognitive function, particularly memory and executive function, improve post the transplant with concurrent improvements in white matter integrity in tracts associated with memory and executive function. These data suggest that abnormalities in cognition and brain structure seen in the ESRD population are at least partially reversible.