Loading...
Light has long-lasting effects on functions ranging from response to threats (NEJM JW Psychiatry Mar 14 2014) to learning. These effects appear to be related to changes in circadian rhythms driven by the suprachiasmatic nucleus (SCN) of the hypothalamus. To determine how circadian rhythms are reprogrammed, European investigators compared methylation of SCN genes in young mice entrained to 22- or 24-hour days.
In animals entrained to the shorter day, compared with those entrained to the normal day, 1294 SCN genes involved in synaptic function were hyper- or hypo-methylated in the promoter region. Periods of activity in the dark (free running) were shortened in the 22-hour animals, and this alteration was associated with changes in methylation…