Dynamics of excitation and inhibition underlying stimulus selectivity in rat somatosensory cortex
Dynamics of excitation and inhibition underlying stimulus selectivity in rat somatosensory cortex
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DOI：
10.1038/nn1545
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发表时间：
2005-10-01
影响因子：
25
通讯作者：
Contreras, D
中科院分区：
文献类型：
--
作者：
Wilent, WB;Contreras, D
感觉系统中的神经元对它们的感受野内的刺激作出反应，但反应的幅度取决于特定的刺激特征。在啮齿动物的触须系统中，对特定触须的偏转的响应幅度在大多数细胞中取决于偏转的方向。在这里，我们使用在体内的细胞内记录从丘脑感受器神经元在第3层和第4层的大鼠桶皮质阐明的动态突触输入的方向选择性。我们发现，尽管广泛调谐的兴奋性和抑制性突触输入，细胞的方向选择性。选择性来自于兴奋相对于抑制的方向依赖性时间移位。对于偏好的方向偏转，兴奋先于抑制，但随着方向偏离偏好，这种分离减小。我们的研究结果说明了一种机制，突触输入的时间，而不是他们的相对峰值幅度，主要决定功能的选择性。
Neurons in sensory systems respond to stimuli within their receptive fields, but the magnitude of the response depends on specific stimulus features. In the rodent whisker system, the response magnitude to the deflection of a particular whisker is, in most cells, dependent on the direction of deflection. Here we use in vivo intracellular recordings from thalamorecipient neurons in layers 3 and 4 of the rat barrel cortex to elucidate the dynamics of the synaptic inputs underlying direction selectivity. We show that cells are direction selective despite a broadly tuned excitatory and inhibitory synaptic input. Selectivity emerges from a direction-dependent temporal shift of excitation relative to inhibition. For preferred direction deflections, excitation precedes inhibition, but as the direction diverges from the preferred, this separation decreases. Our results illustrate a mechanism by which the timing of the synaptic inputs, and not their relative peak amplitudes, primarily determine feature selectivity.