Cortical control of adaptation and sensory relay mode in the thalamus
Cortical control of adaptation and sensory relay mode in the thalamus
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DOI：
10.1073/pnas.1318665111
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发表时间：
2014-05-06
影响因子：
11.1
通讯作者：
Groh, Alexander
中科院分区：
文献类型：
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作者：
Mease, Rebecca A.;Krieger, Patrik;Groh, Alexander
丘脑的主要突触输入源自皮质第 6 层 (L6) 的神经元；然而，这种皮质丘脑通路在感觉处理过程中的功能尚不清楚。在小鼠胡须系统中，我们发现体内 L6 的光遗传学刺激会导致丘脑目标神经元发生超极化和去极化的混合状态。超极化是短暂的，对于较长的 L6 激活（> 200 ms），丘脑神经元达到去极化静息膜电位，这影响了丘脑感觉处理的关键特征。最重要的是，L6 刺激减少了丘脑对重复胡须刺激的反应的适应，从而允许丘脑神经元传递更高频率的感觉输入。此外，L6 通过将丘脑皮质传输从突发转变为单尖峰来控制丘脑反应模式。细胞内感觉反应的分析表明，L6 通过控制静息膜电位和瞬时钙电流 I-T（丘脑兴奋性的标志）的可用性来影响这些丘脑特性。总之，丘脑的 L6 输入可以塑造到达皮质的感觉反应的整体增益和时间动态。
A major synaptic input to the thalamus originates from neurons in cortical layer 6 (L6); however, the function of this cortico-thalamic pathway during sensory processing is not well understood. In the mouse whisker system, we found that optogenetic stimulation of L6 in vivo results in a mixture of hyperpolarization and depolarization in the thalamic target neurons. The hyperpolarization was transient, and for longer L6 activation (>200 ms), thalamic neurons reached a depolarized resting membrane potential which affected key features of thalamic sensory processing. Most importantly, L6 stimulation reduced the adaptation of thalamic responses to repetitive whisker stimulation, thereby allowing thalamic neurons to relay higher frequencies of sensory input. Furthermore, L6 controlled the thalamic response mode by shifting thalamo-cortical transmission from bursting to single spiking. Analysis of intracellular sensory responses suggests that L6 impacts these thalamic properties by controlling the resting membrane potential and the availability of the transient calcium current I-T, a hallmark of thalamic excitability. In summary, L6 input to the thalamus can shape both the overall gain and the temporal dynamics of sensory responses that reach the cortex.