Muistijälkien kirjoittaminen aivojen kovalevylle unen aikana takkuilee Alzheimerin taudissa

”Why do we need to sleep?” is still a question with no unambiguous answer. New findings from brain research suggest that one important function of sleep is to enable the transfer of temporary memories from deep brain structures to long-term storage in the cerebral cortex. This article describes from step to step how this process is thought to occur at the level of a single neuron and neural networks. The transfer of episodic memories from the hippocampus in the medial temporal lobe to the cerebral cortex explains a well-known paradox: an elderly person with Alzheimer’s disease can remember even small details of decade-old events but fails to remember what happened only a few hours ago. Transfer of the memory engram particularly during sleep and typical sleep fragmentation at early stages of Alzheimer’s disease can at least partly account for the poor memory of recent events. A better understanding of the underlying factors and mechanisms can help us develop new treatments to strengthen the weak parts in this chain of events and thereby enhance remembering of new events.