Central versus peripheral determinants of patterned spike activity in rat vibrissa cortex during whisking
Central versus peripheral determinants of patterned spike activity in rat vibrissa cortex during whisking
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DOI：
10.1152/jn.1997.78.2.1144
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发表时间：
1997-08-01
影响因子：
2.5
通讯作者：
Kleinfeld, D
中科院分区：
文献类型：
--
作者：
Fee, MS;Mitra, PP;Kleinfeld, D
本文报道了大鼠初级体感触须皮层单个单元活动与触须节律性运动的关系。动物们被训练成在空中自由地摆动以寻找食物。肌电图（EMG）的记录可作为触须位置的参考。一个快速的，振荡成分在单单位尖峰序列是相关的，与振动的位置在拂动周期。不同单位的相关相位分布较广。第二个缓慢变化的脉冲活动成分与脉冲周期的振幅相关。对于某些单元，相位和振幅相关性具有足够的强度，可以从单个尖峰序列中准确预测晶须的位置。为了确定所观察到的脉冲活动是否由触须运动驱动，而不是由中枢通路驱动，我们在行为任务期间可逆地阻断对侧面部运动神经，使大鼠只在同侧快速。同侧肌电图可作为可靠的参考信号。当面部运动神经被阻断时，峰值-肌电图相关的快速振荡成分消失。这意味着触须在一个周期内的位置是通过直接的感官激活来编码的。峰电位-肌电图相关性的缓慢变化部分不受阻滞的影响。这意味着搅拌的振幅很可能是由相应的放电调节的。我们的研究结果表明，运动皮层并没有传递一个参考信号给感觉皮层，以获取振动过程中触须的位置信息。
We report on the relationship between single-unit activity in primary somatosensory vibrissa cortex of rat and the rhythmic movement of vibrissae. Animals were trained to whisk freely in air in search of food. Electromyographic (EMG) recordings from the mystatial pads served as a reference for the position of the vibrissae. A fast, oscillatory component in single-unit spike trains is correlated with vibrissa position within the whisk cycle. The phase of the correlation for different units is broadly distributed. A second, slowly varying component of spike activity correlates with the amplitude of the whisk cycle. For some units, the phase and amplitude correlations were of sufficient strength to allow the position of the whiskers to be accurately predicted from a single spike train. To determine whether the observed patterned spike activity was driven by motion of the vibrissae, as opposed to central pathways, we reversibly blocked the contralateral facial motor nerve during the behavioral task so that the rat whisked only on the ipsilateral side. The ipsilateral EMG served as a reliable reference signal. The fast, oscillatory component of the spike-EMG correlation disappears when the facial motor nerve is blocked. This implies that the position of vibrissae within a cycle is encoded through direct sensory activation. The slowly varying component of the spike-EMG correlation is unaffected by the block. This implies that the amplitude of whisking is likely to be mediated by corollary discharge. Our results suggest that motor cortex does not relay a reference signal to sensory cortex for positional information of the vibrissae during whisking.