Encoding of tactile stimulus location by somatosensory thalamocortical ensembles
Encoding of tactile stimulus location by somatosensory thalamocortical ensembles
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DOI：
10.1523/jneurosci.20-10-03761.2000
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发表时间：
2000-05-15
影响因子：
5.3
通讯作者：
Nicolelis, MAL
中科院分区：
文献类型：
--
作者：
Ghazanfar, AA;Stambaugh, CR;Nicolelis, MAL
大鼠躯体感觉系统的精致模块化解剖结构使其成为测试用于区分触觉刺激位置的潜在编码策略的极好模型。在这里，我们研究了如何合奏的同时记录在第V层的初级体感（SI）皮层和丘脑的腹后内侧（VPM）核的麻醉大鼠的单个晶须刺激的位置编码在一个单一的审判的基础上的单个神经元。一种基于学习矢量量化算法的人工神经网络，被用来识别假定的编码机制。我们的数据表明，这些神经合奏可能依赖于一个分布式的编码方案，以代表单须刺激的位置。在这个方案中，神经元放电率的时间调制，以及神经元之间的时间相互作用，对刺激位置的表示做出了显着贡献。这些时间代码的相对贡献增加的胡须，合奏必须区分之间的数量。我们的研究结果还表明，SI皮层和VPM核可能作为一个单一的实体编码刺激的位置。总体而言，我们的数据表明，在大鼠三叉神经系统的体感功能的代表性可能会出现从SI皮质和VPM核内和之间的神经元的相互作用。此外，可以同时使用多种编码策略来表示触觉刺激的位置。
The exquisite modular anatomy of the rat somatosensory system makes it an excellent model to test the potential coding strategies used to discriminate the location of a tactile stimulus. Here, we investigated how ensembles of simultaneously recorded single neurons in layer V of primary somatosensory (SI) cortex and in the ventral posterior medial (VPM) nucleus of the thalamus of the anesthetized rat may encode the location of a single whisker stimulus on a single trial basis. An artificial neural network based on a learning vector quantization algorithm, was used to identify putative coding mechanisms. Our data suggest that these neural ensembles may rely on a distributed coding scheme to represent the location of single whisker stimuli. Within this scheme, the temporal modulation of neural ensemble firing rate, as well as the temporal interactions between neurons, contributed significantly to the representation of stimulus location. The relative contribution of these temporal codes increased with the number of whiskers that the ensembles must discriminate among. Our results also indicated that the SI cortex and the VPM nucleus may function as a single entity to encode stimulus location. Overall, our data suggest that the representation of somatosensory features in the rat trigeminal system may arise from the interactions of neurons within and between the SI cortex and VPM nucleus. Furthermore, multiple coding strategies may be used simultaneously to represent the location of tactile stimuli.