[Show abstract][Hide abstract] ABSTRACT: The activity of dopamine-dependent retinal signaling can be assessed using electroretinography. Response of this system to oral food stimulation might provide accessible insight into the brain dopamine response to oral stimuli as retinal dopamine concentration is dependent upon mid brain dopamine concentration was postulated.
Nine individuals had cone ERG (b wave) response to oral food stimulation and oral methylphenidate (MPH) administration measured on separate days, and completed self reported eating behavior questionnaires.
Significant and similar increases in b wave response to both stimuli (P = 0.012 and P = 0.042, MPH and food, respectively) and significant correlations of the food stimulated b wave amplitude with binge eating related behavior as measured by the Gormally Binge Eating Scale (r = 0.68, P = 0.044) and self-reported trait hunger as measured by the Stunkard and Messick Three Factor Eating Questionnaire (r = 0.67, P = 0.048) were found.
The significant increase in food stimulated dopamine dependent b wave amplitude and correlation with methylphenidate stimulated b wave amplitude suggest that ERG may offer a relatively inexpensive and accessible methodology for potentially assess dopaminergic responses to food and other externally applied stimuli that have been implicated in the pathogenesis of a number of human diseases.
[Show abstract][Hide abstract] ABSTRACT: Cortical thickness of the cognitive control network was contrasted between obese (OB), successful weight loss maintainers (SWLM), and lean individuals. OB individuals had significant thinning, most notably in the anterior cingulate and posterior parietal cortices. SWLM individuals exhibited trends towards thicker cortex than OB individuals, which may be important in future studies.
Psychiatry Research 05/2012; 202(1):77-9. · 2.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: As many people struggle with maintenance of weight loss, the study of successful weight loss maintainers (SWLM) can yield important insights into factors contributing to weight loss maintenance. However, little research has examined how SWLM differ from people who are obese or normal weight (NW) in brain response to orosensory stimulation. The goal of this study was to determine if SWLM exhibit different brain responses to orosensory stimulation. Brain response to one-minute orosensory stimulation with a lemon lollipop was assessed using functional magnetic resonance imaging (FMRI) among 49 participants, including SWLM (n=17), NW (n=18) and obese (n=14) controls. Significant brain responses were observed in nine brain regions, including the bilateral insula, left inferior frontal gyrus, left putamen, and other sensory regions. All regions also exhibited significant attenuation of this response over one minute. The SWLM exhibited greater response compared to the other groups in all brain regions. Findings suggest that the response to orosensory stimulation peaks within 40 seconds and attenuates significantly between 40-60 seconds in regions associated with sensation, reward, and inhibitory control. Greater reactivity among the SWLM suggests that greater sensory reactivity to orosensory stimulation, increased anticipated reward, and subsequently greater inhibitory processing are associated with weight loss maintenance.
[Show abstract][Hide abstract] ABSTRACT: We studied whether self-reported intent to exert cognitive control over eating was associated with differences in brain response to food cues, independent of genetic background. Subjects were ten pairs of identical twins in which one twin was a restrained eater and the co-twin was unrestrained, as classified by the Herman and Polivy Restraint Scale. Before and after ingestion of a milkshake, we used functional magnetic resonance imaging to measure brain response to photographs of objects, "fattening" food, and "non-fattening" food. At baseline, restrained eaters had greater activation in the left amygdala and the right thalamus in response to fattening food cues than did their unrestrained co-twins. When restrained eaters drank a milkshake, activation in response to fattening food photographs decreased across multiple brain areas, whereas activation induced by non-fattening food photographs increased. As compared to their unrestrained co-twins, restrained eaters who drank a milkshake had greater decreases in activation by fattening food images in the left amygdala and occipital lobe, and greater increases in activation by non-fattening food images in the medial orbitofrontal cortex. Because of the discordant monozygotic twin study design, the findings provide a rigorous level of support for the hypothesis that adopting an intention to restrain eating alters brain response to food cues.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to characterize the psychoactive effects of tasting chocolate and to evaluate the contribution of the main chocolate components to the desire to consume more of it. A total of 280 participants, (F-155; M=125) ranging in age from 18-65, completed the study. Participants were randomly assigned to taste 12.5 g of either white chocolate ("control") or one of four chocolate ("cocoa") samples varying in sugar, fat and percent cocoa content, then answered the question: "Do you want more of this chocolate?" and "If yes, how many more pieces of this chocolate would you like to eat?" They completed pre- and post-consumption surveys, consisting of 30 questions derived from the Addiction Research Center Inventory (ARCI) subscales, Morphine-Benzedrine Group (MBG), Morphine (M) and Excitement (E). Significant decreases in post-pre consumption changes in MBG subscale were observed between the control sample and the 70% cocoa (p=0.046) or the 85% cocoa sample (p=0.0194). Proportionally more men than women wanted more of the tasted chocolate (p=0.035). Participants were more likely to want more of the tasted chocolate if they displayed a greater change in the MBG scale, and if their chocolate sample had high sugar and cocoa content, as assessed by multiple logistic regression. Our results suggest that multiple characteristics of chocolate, including sugar, cocoa and the drug-like effects experienced, play a role in the desire to consume chocolate.
[Show abstract][Hide abstract] ABSTRACT: Prior research indicates that successful weight-loss maintainers (SWLs) work harder than people of normal weight to maintain their weight loss, including greater dietary restriction of fat and higher physical activity levels. However, little work to date has examined how SWLs differ biologically from normal-weight (NW) and obese controls.
The objective was to compare the brain responses of SWLs to food pictures with those of NW and obese controls.
Blood oxygen level-dependent responses to high- and low-energy food pictures were measured in 18 NW controls, 16 obese controls, and 17 SWLs.
Group differences were identified in 4 regions, which indicated significant change in activation in response to the food pictures. SWLs showed greater activation in the left superior frontal region and right middle temporal region than did NW and obese controls-a pattern of results confirmed in exploratory voxel-wise analyses. Obese controls also showed greater activation in a bilateral precentral region.
These results suggest that SWLs show greater activation in frontal regions and primary and secondary visual cortices-a pattern consistent with greater inhibitory control in response to food cues and greater visual attention to the food cues. A greater engagement of inhibitory control regions in response to food cues as well as a greater monitoring of foods may promote control of food intake and successful weight-loss maintenance.
American Journal of Clinical Nutrition 09/2009; 90(4):928-34. · 6.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The temporal relationship between depression and cognitive decline has not been extensively investigated in prospective population-based studies, and most of these have only looked in one direction. We estimated the bidirectional temporal relationship between depressive symptoms and cognitive function in older subjects, excluding subjects with a clinical diagnosis of dementia or mild cognitive impairment (MCI). In a total of 2,963 individuals from the Italian Longitudinal Study on Aging, depressive symptoms, global cognitive function, and episodic memory were measured. Dementia, Alzheimer's disease, vascular dementia, and MCI were classified using current clinical criteria. Depressive symptoms at baseline were associated with an accelerated global cognitive function decline and an accelerated rate of episodic memory delayed recall decline in a 3.5-year follow-up. Finally, an accelerated increase with time of depressive symptoms during the same follow-up period was not associated with global cognitive function and episodic memory (immediate and delayed recall). In older subjects non-cognitively impaired, depressive symptoms at baseline predicted change over time of global cognitive decline and episodic memory delayed recall. Global cognitive function and episodic memory at baseline were not associated with the course of depressive symptoms during the follow-up.
[Show abstract][Hide abstract] ABSTRACT: We evaluated the impact of depressive symptoms on the rate of incident mild cognitive impairment (MCI) after a 3.5-year follow-up, and we assessed the interaction between depressive symptoms and vascular risk factors for incident MCI.
A total of 2,963 individuals from a sample of 5,632 65- to 84-year-old subjects were cognitively and functionally evaluated at the 1st and 2nd surveys of the Italian Longitudinal Study on Aging, a prospective cohort study with a 3.5-year follow-up. MCI and dementia were classified using current clinical criteria. Depressive symptoms were measured with the Geriatric Depression Scale.
Among the 2,963 participants, 139 prevalent MCI cases were diagnosed at the 1st survey. During the 3.5-year follow-up, 105 new events of MCI were diagnosed. We did not observe any significant association between depressive symptoms and incident MCI (RR = 1.25, 95% CI = 0.85-1.84, chi(2) = 1.30, p < 0.25). No sociodemographic variables or vascular risk factors modified the relationship between depressive symptoms and incident MCI.
In our population, depressive symptoms were not associated with the rate of incident MCI. Our findings did not support a role of sociodemographic variables or vascular risk factors in the link between depressive symptoms and incident MCI.
[Show abstract][Hide abstract] ABSTRACT: 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.
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).
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.
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.
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.
American Journal of Clinical Nutrition 09/2007; 86(3):573-9. · 6.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To estimate the impact of alcohol consumption on the incidence of mild cognitive impairment and its progression to dementia.
We evaluated the incidence of mild cognitive impairment in 1,445 non-cognitively impaired individuals and its progression to dementia in 121 patients with mild cognitive impairment, aged 65 to 84 years, participating in the Italian Longitudinal Study on Aging, with a 3.5-year follow-up. The level of alcohol consumption was ascertained in the year before the survey. Dementia and mild cognitive impairment were classified using current clinical criteria.
Patients with mild cognitive impairment who were moderate drinkers, i.e., those who consumed less than 1 drink/day (approximately 15 g of alcohol), had a lower rate of progression to dementia than abstainers (hazard ratio [HR] 0.15; 95% CI 0.03 to 0.78). Furthermore, moderate drinkers with mild cognitive impairment who consumed less than 1 drink/day of wine showed a significantly lower rate of progression to dementia than abstainers (HR 0.15; 95% CI 0.03 to 0.77). Finally, there was no significant association between higher levels of drinking (> or =1 drink/day) and rate of progression to dementia in patients with mild cognitive impairment vs abstainers. No significant associations were found between any levels of drinking and the incidence of mild cognitive impairment in non-cognitively impaired individuals vs abstainers.
In patients with mild cognitive impairment, up to 1 drink/day of alcohol or wine may decrease the rate of progression to dementia.
[Show abstract][Hide abstract] ABSTRACT: We estimated the prevalence and incidence rates of depressive symptoms and the role of vascular risk factors and sociodemographic variables on the occurrence of depressive symptoms in mild cognitive impairment (MCI).
In the Italian Longitudinal Study on Aging, 2,963 individuals from 5,632 65- to 84-year-old subjects were evaluated at the 1st and 2nd survey, with a 3.5-year follow-up. Dementia and MCI were classified using current criteria. Depressive symptoms were measured with the Geriatric Depression Scale.
Among the 2,963 participants, 139 prevalent MCI cases were diagnosed with a depressive symptoms prevalence rate of 63.3%. During the 3.5-year follow-up, we estimated an incidence rate of depressive symptoms of 29.6 per 100 person-years. No sociodemographic variables or vascular risk factors modified the incidence of depressive symptoms in cognitively stable MCI patients or in MCI patients who reverted to normal cognition.
In our population, there was a high prevalence and incidence of depressive symptoms in MCI. Our findings do not provide support for a possible role of vascular risk factors in the development of depressive symptoms in MCI, although these findings were based on relatively few cases of MCI, limiting the capacity to draw definitive conclusions.