Nature Neuroscience 9, 398 - 407 (2006)
Published online: 19 February 2006; | doi:10.1038/nn1651
The dorsomedial hypothalamic nucleus is critical for the expression of food-entrainable circadian rhythmsJoshua J Gooley1, 2, Ashley Schomer1
& Clifford B Saper1, 21
Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA. 2
Division of Sleep Medicine and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, USA.
Correspondence should be addressed to Clifford B Saper csaper@caregroup.harvard.edu Circadian rhythms of behavior and physiology can be entrained by daily cycles of restricted food availability, but the pathways that mediate food entrainment are unknown. The dorsomedial hypothalamic nucleus (DMH) is critical for the expression of circadian rhythms and receives input from systems that monitor food availability. Here we report that restricted feeding synchronized the daily rhythm of DMH activity in rats such that c-Fos expression in the DMH was highest at scheduled mealtime. During food restriction, unlesioned rats showed a marked preprandial rise in locomotor activity, body temperature and wakefulness, and these responses were blocked by cell-specific lesions in the DMH. Furthermore, the degree of food entrainment correlated with the number of remaining DMH neurons, and lesions in cell groups surrounding the DMH did not block entrainment by food. These results establish that the neurons of the DMH have a critical role in the expression of food-entrainable circadian rhythms.
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