Epilepsy Center of Excellence, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, USA; Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA.
Epilepsy Center of Excellence, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, USA; Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA; Department of Neurology, University of Washington, Seattle, WA 98195, USA.
Cell Rep. 2022 Feb 15;38(7):110382. doi: 10.1016/j.celrep.2022.110382.
Elucidating how neurons encode network activity is essential to understanding how the brain processes information. Neocortical pyramidal cells receive excitatory input onto spines distributed along dendritic branches. Local dendritic branch nonlinearities can boost the response to spatially clustered and synchronous input, but how this translates into the integration of patterns of ongoing activity remains unclear. To examine dendritic integration under naturalistic stimulus regimes, we use two-photon glutamate uncaging to repeatedly activate multiple dendritic spines at random intervals. In the proximal dendrites of two populations of layer 5 pyramidal neurons in the mouse motor cortex, spatially restricted synchrony is not a prerequisite for dendritic boosting. Branches encode afferent inputs with distinct rate sensitivities depending upon cell and branch type. Thus, inputs distributed along a dendritic branch can recruit supralinear boosting and the window of this nonlinearity may provide a mechanism by which dendrites can preferentially amplify slow-frequency network oscillations.
阐明神经元如何对网络活动进行编码对于理解大脑如何处理信息至关重要。新皮层锥体神经元在沿树突分支分布的棘突上接收兴奋性输入。局部树突分支非线性可以增强对空间上聚类和同步输入的响应，但这如何转化为对持续活动模式的整合尚不清楚。为了在自然刺激条件下检查树突整合，我们使用双光子谷氨酸解笼来以随机间隔反复激活多个树突棘突。在小鼠运动皮层第 5 层锥体神经元的两个群体的近端树突中，空间受限的同步不是树突增强的前提条件。分支根据细胞和分支类型以不同的速率敏感性对传入输入进行编码。因此，沿树突分支分布的输入可以募集超线性增强，而这种非线性的窗口可能为树突优先放大慢频率网络振荡提供了一种机制。
