Inhibition of sensory responses of cat inferior olive neurons produced by stimulation of red nucleus.
Inhibition of sensory responses of cat inferior olive neurons produced by stimulation of red nucleus.
复制标题
抑制红核刺激产生的猫下橄榄神经元的感觉反应。
DOI：
10.1152/jn.1990.64.4.1170
复制
发表时间：
1990
影响因子：
2.5
通讯作者：
Gibson,AR
中科院分区：
文献类型：
--
作者：
Weiss,C;Houk,JC;Gibson,AR
1.已知下橄榄细胞的感觉反应性在活跃运动的某些阶段受到抑制。这些实验旨在测试红核脊髓通路中的活动是否有助于这种抑制。在戊巴比妥钠麻醉的猫，我们记录了位于下橄榄的一个分支--嘴背副橄榄(RDAO)对光触摸敏感的细胞。在向红核脊髓通路传递条件性刺激的过程中和之后，测试对周围刺激的反应性。2.在我们的rDAO神经元样本中，所有44个细胞在红核脊髓通路的条件性刺激后，对外周刺激的反应性都表现出抑制。典型的条件反射序列由200赫兹的0.2毫秒脉冲组成，持续100毫秒。将发射概率降低到0.5所需的平均电流为31微安。强度的轻微增加通常会完全抑制对外周刺激的反应。3.反应抑制表现出延迟的时程。峰值抑制发生在调节序列中最后一个脉冲后约50ms。在许多情况下，在条件化训练期间没有明显的抑制。列车频率、列车持续时间或刺激强度的增加会产生更强烈和更广泛的橄榄抑制期。4.引起rDAO抑制的最低阈值与大细胞红核(RNM)或红核脊髓束(RST)相吻合。刺激RST部位可抑制对侧的反应，但不能抑制同侧rDAO的反应。切断上脑干RST可阻断刺激红核产生的抑制作用，但不改变刺激尾侧束所产生的抑制作用。因此，这种抑制效应似乎是由红核脊髓通路的激活引起的。5.本研究中观察到的抑制时序可能适用于解释在清醒动物中观察到的橄榄糖对接触反应的抑制。运动相关的红核放电通常在运动结束前约50ms停止。这个时序将允许在目标导向的肢体运动结束时与物体接触的大约时间形成峰值抑制。
1. The sensory responsiveness of cells in the inferior olive is known to be suppressed during certain phases of active movement. These experiments were designed to test the possibility that activity in the rubrospinal pathway contributes to this suppression. We recorded from cells sensitive to light touch located in one of the divisions of the inferior olive, the rostral dorsal accessory olive (rDAO), in cats anesthetized with pentobarbitol sodium. Responsiveness to peripheral stimuli was tested during and after trains of conditioning stimuli delivered to the rubrospinal pathway. 2. All 44 cells in our sample of rDAO neurons showed an inhibition of responsiveness to peripheral stimuli after conditioning stimulation of the rubrospinal pathway. Typical conditioning trains consisted of 0.2-ms pulses at 200 Hz for 100 ms. The mean current required for a reduction in firing probability to 0.5 was 31 microA. Slight increases in intensity often completely inhibited responses to peripheral stimuli. 3. Inhibition of responsiveness showed a delayed time course. Peak inhibition occurred approximately 50 ms after the last pulse in the conditioning train. In many cases there was no demonstrable inhibition during the conditioning train. Increases of train frequency, train duration, or stimulus intensity produced stronger and broader periods of olivary inhibition. 4. The lowest threshold points for eliciting rDAO inhibition coincided with either the magnocellular red nucleus (RNm) or the rubrospinal tract (RST). Stimulation at RST sites produced inhibition of responses in the contralateral but not in the ipsilateral rDAO. Transection of the RST in the upper brain stem blocked the inhibition produced by red-nucleus stimulation without altering the inhibition produced by tract stimulation caudal to the transection. The inhibitory effects thus appear to be caused by activation of the rubrospinal pathway. 5. The inhibitory timing observed in this study may be appropriate for explaining the suppression of olivary responsiveness to contact that has been observed in awake animals. Bursts of movement-related, red nucleus discharge often cease approximately 50 ms before the end of movement. This timing would allow peak inhibition to develop at approximately the time of contact with an object at the end of a goal-directed limb movement.