Three-dimensional sensitivity and caudal projection of neck spindle afferents.
Three-dimensional sensitivity and caudal projection of neck spindle afferents.
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颈纺锤体传入的三维敏感性和尾部投射。
DOI：
10.1152/jn.1988.59.5.1497
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发表时间：
1988
影响因子：
2.5
通讯作者：
Wilson,VJ
中科院分区：
文献类型：
--
作者：
Kasper,J;Schor,RH;Yates,BJ;Wilson,VJ
1.用漂浮电极记录去脑猫颈部C2背根节的肌梭传入。这些传入神经可能主要支配脊椎周围腹侧和腹外侧肌，以及胸锁乳突肌。刺激包括旋转头部围绕横摇/俯仰或俯仰/偏航轴的运动的组合。与我们之前的实验(10)的一个重要区别是，偏航运动被添加到刺激范式中，使得对传入行为的三维分析成为可能。2.对于每个传入信号，我们通过使用组合俯仰和横摇或俯仰和偏航的正弦刺激，或者通过测量对横摇、俯仰和偏航旋转的响应的增益，来确定三维中最有效的倾斜方向(响应向量的方向)。3.大多数传入神经对围绕三个轴的旋转都很敏感；俯仰和偏航通常比侧滚更有效。没有反应载体聚集的迹象，如果受体位于一小部分肌肉中，每一块肌肉的受体都以相同的方向排列，那么可能会出现这种情况。4.用正弦和梯形刺激与其反应向量的方向尽可能紧密地对齐，进一步研究传入神经的反应。偏航刺激的可用性使得基于响应线性度、增益和动态指数的感受器分类比我们先前的实验更可靠(10)。5.肌梭反应分为A、B和模糊三种类型。有证据表明，A类受体可能是纺锤体初级受体，B类受体可能是次级受体。模棱两可的受体具有中间特性。6.在同侧背柱表面用可移动电极传递逆行刺激，观察梭形传入的尾侧投射。18%的传入神经投射到C4，14%投射到C5。在A、B和具有一系列方向敏感性的模糊受体中可以发现长尾投射。7.证据表明，颈中节段的C2纺锤传入神经元与颈椎强直反射的脊髓内通路中的中间神经元和固有脊髓神经元形成突触。
1. We recorded from neck muscle spindle afferents in the C2 dorsal root ganglion of the decerebrate cat using floating electrodes. The afferents presumably innervated mainly ventral and ventrolateral perivertebral muscles, and sternocleidomastoid. Stimuli consisted of combinations of rotatory head movements about the roll/pitch or pitch/yaw axes. An important difference from our earlier experiments (10) was the addition of yaw movement to the stimulus paradigm making possible a three-dimensional analysis of afferent behavior. 2. For each afferent we determined the most effective direction of tilt (orientation of the response vector) in three dimensions by using sinusoidal stimuli that combined pitch and roll, or pitch and yaw, or by measuring the gains to responses to roll, pitch, and yaw rotation. 3. Most afferents were sensitive to rotation around all three axes; pitch and yaw were usually more effective than roll. There was no indication of clustering of response vectors, as might be expected if the receptors were located in a small number of muscles each of which has receptors aligned in a homogeneous direction. 4. The responses of afferents were further studied using sinusoidal and trapezoidal stimuli aligned as closely as possible with the orientation of their response vector. The availability of the yaw stimulus made receptor classification based on response linearity, gain, and dynamic index more reliable than in our earlier experiments (10). 5. Muscle spindle responses were divided into three categories: A, B, and ambiguous. The evidence suggests that category A are probably spindle primary receptors and category B are secondaries. Ambiguous receptors have intermediate properties. 6. The caudal projection of spindle afferents was examined by delivering antidromic stimuli with a movable electrode on the surface of the ipsilateral dorsal column. Eighteen percent of the afferents projected to C4, and 14% as far as C5. Long caudal projections can be found in A, B, and ambiguous receptors with a range of directional sensitivities. 7. The evidence suggests that C2 spindle afferents make synapses in the midcervical segments with interneurons and propriospinal neurons that are part of the intraspinal pathway of the tonic neck reflex.