作者: Masaru Ishibashi , Iryna Gumenchuk , Bryan Kang , Catherine Steger , Elizabeth Lynn
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摘要: A hallmark of the waking state is a shift in EEG power to higher frequencies with epochs synchronized intracortical gamma activity (30-60 Hz) - process associated high-level cognitive functions. The ascending arousal system, including cholinergic laterodorsal (LDT) and pedunculopontine (PPT) tegmental neurons serotonergic dorsal raphe (DR) neurons, promotes this state. Recently, system has been proposed as wave generator, part, because some produce high-threshold, Ca(2+)-dependent oscillations at frequencies. However, it not known whether arousal-related inputs these generate such oscillations, or are ever transmitted neuronal targets. Since key input arises from hypothalamic orexin (hypocretin) we investigated unusually noisy, depolarizing current could provide significant drive oscillations. Whole-cell recordings brain slices were obtained mice expressing Cre-induced fluorescence LDT PPT, DR neurons. After first quantifying reporter expression accuracy found that produced high frequency, gamma, both Then, by using dynamic clamp, adding noisy conductance induced resonance peaked theta alpha frequency range (4-14 extended up 100 Hz. We propose noise Ca(2+) dependent work synergistically boost encoding high-frequency synaptic into action potentials help ensure fire during activation. This reinforce thalamocortical states supporting arousal, REM sleep, gamma.