Events at Physics |
Events on Tuesday, January 22nd, 2008
- Chaos & Complex Systems Seminar
- Sleep need and synaptic homeostasis
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: Chiara Cirelli, UW Department of Psychiatry
- Abstract: Any proposal about the function of sleep should be able to provide a convincing explanation of why the proposed function can only be fulfilled by sleep and not by quiet wakefulness. Otherwise, why would sleep--a potentially dangerous behavior characterized by loss of contact with the environment--be so universal, and why would sleep pressure be so overwhelming? I will discuss a novel hypothesis--the synaptic homeostasis hypothesis (SHY)--which claims that sleep plays a role in the regulation of synaptic weight in the brain. SHY states that during wakefulness many brain circuits undergo synaptic potentiation, resulting in a net increase in the strength of synaptic connections between neurons, and that the homeostatic increase in slow wave activity (SWA) during the subsequent sleep is a direct reflection of this synaptic potentiation. SHY also predicts that SWA mediates synaptic downscaling, which is tied to several beneficial effects of sleep, including performance enhancement. In summary, according to this hypothesis, sleep is the price we have to pay for plasticity, and its goal is the homeostatic regulation of the total synaptic weight impinging on neurons. I will discuss evidence supporting the hypothesis, its implications, as well as current limitations and unresolved issues.