Imaging in vivo brain-hormone interaction in the control of eating and obesity.

The field of neuroimaging has made great progress in the mapping of human brain function. In this article, we present a functional magnetic resonance imaging (fMRI) study on the hypothalamic regulation of satiety and its relationship with obesity. The fMRI techniques have been proven invaluable for analyzing changes in brain activity that are associated with most sensorimotor and cognitive functions. However, few studies have been successful in the delineation of the interaction between the central nervous system and the endocrine system, due to the lack of suitable mapping methods which can pinpoint the onset of changes in neuronal activity (e.g., those following eating or drug intake). We have recently introduced a new fMRI method known as temporal clustering analysis (TCA) for dynamically tracking the time course of brain activation. Along with simultaneous blood sampling for the circulating hormone levels, the fMRI techniques with TCA may provide an integrated view of the nervous and endocrine systems in vivo, and thus greatly enhance our understanding of the complex interplay between neural events and hormonal signals.