Hibernating animals rapidly restore cognitive function after long periods of dormancy. Evidence suggests learning is enhanced (Mihailović et al., 1968) and cold-induced memory impairment attenuated (McNamara et al., 1973) following hibernation. Restorative processes involving pruning and regeneration of synapses during hibernation or arousal could restore cognitive function following prolonged sleep deprivation or other stressors (Popov and Bocharova, 1992; Popov et al., 1992; Kavanau, 1997). Current research uses behavioral measures to study effects of hibernation on memory. Factors associated with hibernation may play a role in synaptic remodeling during hibernation and sleep.