The biological clock in mammals is located in the suprachiasmatic nucleus (SCN) and regulates daily and seasonal rhythms. The research presented in this thesis consists of behavioral and... Show moreThe biological clock in mammals is located in the suprachiasmatic nucleus (SCN) and regulates daily and seasonal rhythms. The research presented in this thesis consists of behavioral and electrophysiological experiments to investigate the SCN as a pacemaker of daily and seasonal rhythms. We investigated the activity of single neurons and small groups of neurons in the SCN and their role in photoperiodic adaptations. We found that single cells in the SCN do not code for the length of day, but that photoperiodic encoding is a property of the SCN neuronal network. Show less