Influence of VPM afferents on putative inhibitory interneurons in S1 of the awake rabbit: evidence from cross-correlation, microstimulation, and latencies to peripheral sensory stimulation.
Influence of VPM afferents on putative inhibitory interneurons in S1 of the awake rabbit: evidence from cross-correlation, microstimulation, and latencies to peripheral sensory stimulation.
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VPM 传入对清醒兔子 S1 中假定的抑制性中间神经元的影响：来自互相关、微刺激和外周感觉刺激潜伏期的证据。
DOI：
10.1152/jn.1995.73.4.1584
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Swadlow,HA
中科院分区：
文献类型：
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作者：
Swadlow,HA
1.丘脑皮质投射神经元和可疑的皮质中间神经元（SIN）非常简短的外周刺激的反应进行了检查内的触须，窦毛，嘴唇，和下巴的腹后内侧丘脑（VPM）和初级体感皮层（S1）的代表。VPM丘脑皮质神经元（N = 40）被确定其逆行激活后，电刺激S1。通过由一个或多个传入通路的阈上刺激引起的三个或更多个尖峰的高频（> 600 Hz）爆发来识别SIN。SIN也具有非常短的持续时间的尖峰。2.以前的工作表明，电刺激VPM在许多S1 SIN中引起非常早期和强大的突触反应。采用三种实验策略来检验这一假设，即这种反应反映了单突触VPM输入到SIN，并检查这种输入的影响。1)在短暂的外周刺激后，VPM丘脑皮层冲动在S1的到达时间进行了测定，并与S1 SIN的初始反应时间进行了比较。2)位移校正交叉相关图（CCG）构建从锋电位列车的VPM神经元和SIN，在精确的地形对齐。3)通过将非常低强度（1-10微安）的微刺激脉冲施加到VPM中的记录微电极并观察皮层SIN中的诱发反应，支持基于此类CCG的连接性推断。3. VPM丘脑皮质神经元对短暂的空气刺激反应的中位潜伏期为5.05 ms，在S1的VPM脉冲的估计到达时间的中值为5.97 ms。该估计是通过将每个VPM神经元的逆向潜伏期与外周刺激的潜伏期相加而获得的，并且得到了从接近其终止记录的三个VPM丘脑皮质轴突获得的类似值的支持S1内的站点。S1的SIN是最早对外周刺激作出反应的皮层神经元之一，对空气抽吸的中位潜伏期为6.6 ms（范围5.7-13.0 ms）。SINS对周围刺激的潜伏期与VPM对粗大电刺激的潜伏期呈显著正相关（中位数1.52ms，r2 =+0.44，P < 0.0001）。许多SINs（34个中的23个）表现出显着的位移校正CCG，VPM神经元处于精确的地形对齐。大多数重要的CCG显示SIN尖峰概率（约1 ms的半幅响应）非常短暂的增加，在VPM尖峰后1.4-2.0 ms的间隔达到峰值。（400字处截断摘要）
1. Responses of thalamocortical projection neurons and suspected cortical interneurons (SINs) to very brief peripheral stimuli were examined within the vibrissae, the sinus hair, the lip, and the chin representations of ventroposterior medial thalamus (VPM) and primary somatosensory cortex (S1). VPM thalamocortical neurons (N = 40) were identified by their antidromic activation after electrical stimulation of S1. SINs were identified by a high-frequency (> 600 Hz) burst of three or more spikes elicited by suprathreshold stimulation of one or more afferent pathways. SINs also had spikes of very short duration. 2. Previous work has shown that electrical stimulation of VPM elicits a very early and powerful synaptic response in many S1 SINs. Three experimental strategies were employed to test the hypothesis that such responses reflect a monosynaptic VPM input onto SINs and to examine the effects of such input. 1) After a brief peripheral stimulus, the arrival times of VPM thalamocortical impulses in S1 were determined and compared with the initial response times of S1 SINs. 2) Shift-corrected cross-correlograms (CCGs) were constructed from the spike trains of pairs of VPM neurons and SINs that were in precise topographic alignment. 3) Inferences of connectivity based on such CCGs were supported by applying very low-intensity (1-10 microA) microstimulation pulses to the recording microelectrode in VPM and observing evoked responses in the cortical SIN. 3. VPM thalamocortical neurons responded to a brief air puff stimulus at a median latency of 5.05 ms, and the estimated arrival time of the VPM impulses at S1 had a median value of 5.97 ms. This estimate was obtained by adding the antidromic latency of each VPM neuron to the latency of the peripheral stimulus and was supported by similar values obtained from three VPM thalamocortical axons recorded near their termination site within S1. SINs of S1 were among the first cortical neurons to respond to the peripheral stimulus, responding to the air puff at a median latency of 6.6 ms (range 5.7-13.0 ms). The latency of SINs to the peripheral stimulus was strongly related to the latency to gross electrical stimulation of VPM (median value 1.52 ms, r2 = +0.44, P < 0.0001). Many SINs (23 of 34) showed significant shift-corrected CCGs with VPM neurons that were in precise topographic alignment. Most significant CCGs revealed a very brief increase in SIN spike probability (half-amplitude response of approximately 1 ms) that reached a peak value at intervals of 1.4-2.0 ms after the VPM spike.(ABSTRACT TRUNCATED AT 400 WORDS)