Tactile responses of hindpaw, forepaw and whisker neurons in the thalamic ventrobasal complex of anesthetized rats
Tactile responses of hindpaw, forepaw and whisker neurons in the thalamic ventrobasal complex of anesthetized rats
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DOI：
10.1111/j.1460-9568.2008.06025.x
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发表时间：
2008-01-01
影响因子：
3.4
通讯作者：
Foffani, G.
中科院分区：
文献类型：
--
作者：
Aguilar, J.;Morales-Botello, M. L.;Foffani, G.
大多数研究丘脑皮质神经元对触觉刺激的反应都集中在大鼠丘脑的胡须表征上：腹侧后内侧核（VPM）。为了测试丘脑皮质对触觉刺激的反应的基本特性是否可以扩展到整个腹基底复合体，我们记录了来自胡须、前爪和后爪丘脑表征的单个神经元。我们对两种不同麻醉剂（戊巴比妥或尿烷）下对刻板触觉刺激（即 500 毫秒脉冲（即开关刺激）或 1 毫秒脉冲（即脉冲刺激））的反应进行了系统分析。我们获得了以下主要结果：（i）细胞对 ON 与 OFF 刺激的调节在神经元之间显示出梯度，因此三分之二的细胞对 ON 刺激反应更多，三分之一的细胞对 OFF 刺激反应更多； (ii) 平均而言，ON 和 OFF 刺激之间的反应幅度没有差异，而对 OFF 刺激的反应延迟要长几毫秒； (iii) 对 ON 和 OFF 刺激的反应潜伏期高度相关； (iv) 对冲动刺激和ON刺激的反应表现出很强的相关性，而对冲动刺激和OFF刺激的反应之间的关系则更为微妙； (v) 与 ON 反应不同，当刺激从感受野中心移动到兴奋性周围的较近位置时，OFF 反应不会减少。我们对后爪、前爪和胡须神经元获得了相同的结果。我们的结果支持神经生理学同质腹基底复合体的观点，其中 OFF 反应参与丘脑皮层神经元触觉刺激的时空感受野的结构。
The majority of studies investigating responses of thalamocortical neurons to tactile stimuli have focused on the whisker representation of the rat thalamus: the ventral-posterior-medial nucleus (VPM). To test whether the basic properties of thalamocortical responses to tactile stimuli could be extended to the entire ventrobasal complex, we recorded single neurons from the whisker, forepaw and hindpaw thalamic representations. We performed a systematic analysis of responses to stereotyped tactile stimuli - 500 ms pulses (i.e. ON-OFF stimuli) or 1 ms pulses (i.e. impulsive stimuli) - under two different anesthetics (pentobarbital or urethane). We obtained the following main results: (i) the tuning of cells to ON vs. OFF stimuli displayed a gradient across neurons, so that two-thirds of cells responded more to ON stimuli and one-third responded more to OFF stimuli; (ii) on average, response magnitudes did not differ between ON and OFF stimuli, whereas latencies of response to OFF stimuli were a few milliseconds longer; (iii) latencies of response to ON and OFF stimuli were highly correlated; (iv) responses to impulsive stimuli and ON stimuli showed a strong correlation, whereas the relationship between the responses to impulsive stimuli and OFF stimuli was subtler; (v) unlike ON responses, OFF responses did not decrease when stimuli were moved from the receptive field center to a close location in the excitatory surround. We obtained the same results for hindpaw, forepaw and whisker neurons. Our results support the view of a neurophysiologically homogeneous ventrobasal complex, in which OFF responses participate in the structure of the spatiotemporal receptive field of thalamocortical neurons for tactile stimuli.