Neuroimaging-Verfahren in der Adipositasforschung [Neuroimaging in obesity research]

Neuroimaging Technologies in Obesity Research. Neurological correlates of obesity have been extensively discussed and investigated over the last few years. Use of neuroima ging technology provides novel ap- proaches to obesity research. Among these, magnetic resonance imaging (MRI) and positron emission tomography (PET) appear to be most promising. Due to the great variability of con- founding factors on brain development many selection criteria have to be fulfi lled in order to assure the reliability of a neuroimaging study. The number of highly capable MRI and PET in- vestigation centers is increasing, especially in large urban areas where highly characterized cohorts of subjects can be recruited. Recent in- vestigations have shown that the human brain receives and distributes homeostatic and he- donic impulses to regulate eating behavior. Both hunger and appetite are distinct aspects of the drive to eat originating in different brain areas, yet subject to a common regulating center. The responsible areas appear to be structurally and functionally altered in obesity, including chang- es in the reward system. Women and men (both lean and obese) seem to respond differentially to homeostatic and hedonic stimuli for hunger and satiety. The “hun ger networks” are affect- ed by genetic, biochemical, hormonal, neuronal, and other factors. For example ghrelin, peptide YY, and leptin are claimed to be endocrine sig- nals from the gastro intes ti nal tract and adipose tissue not only regulating metabolic activity and nutrient distribution but also possessing central nervous effects. These hormones act as short- time or long-time modulators of specifi c brain areas with homeostatic or hedonic power on food evaluation and eating behavior. Know- ing the interactions of certain brain regions in the regulation of hunger/appetite and satiety/ satiation will allow for the development of new therapeutic agents against obesity