Kleine J F, Guan Y, Kipiani E, Glonti L, Hoshi M, Büttner U
Department of Neurology, Ludwig Maximilian University, D 81377 Munich, Germany.
J Neurophysiol. 2004 May;91(5):2090-100. doi: 10.1152/jn.00849.2003.
Vestibulospinal reflexes play an important role for body stabilization during locomotion and for postural control. For an appropriate distribution of vestibular signals to spinal motoneurons, the orientation of the body relative to the head needs to be taken into account. For different trunk positions, identical vestibular stimuli must activate different sets of muscles to ensure body stabilization. Because the cerebellar vermis and the underlying fastigial nucleus (FN) might be involved in this task, vestibular neurons in the rostral FN of alert rhesus monkeys were recorded during sinusoidal vestibular stimulation (0.1-1.0 Hz) in the roll and pitch planes at different trunk-re-head positions (center and +/-45 degrees ). From the sensitivity and phase values measured in these planes, the response properties in the intermediate planes and the stimulus orientation eliciting the optimal response [response vector orientation (RVO)] were calculated. In most neurons, the RVOs rotated systematically with respect to the head, when trunk-re-head position was altered, so that they tended to maintain their orientation with respect to the trunk. Sensitivity and phase at the RVO were not affected. This pattern was the same for neurons in the right and left FN and independent of stimulus frequency. The average sensitivity of this partially compensatory RVO shift in response to trunk-re-head displacements, evaluated by linear regression analyses, was 0.59 degrees / degrees (n = 73 neurons). These data show that FN neurons may encode vestibular information in a coordinate system that is closer to a trunk-centered than to a head-centered reference frame. They indicate an important role of this nucleus in motor programs related to posture and gait control.
前庭脊髓反射在运动过程中的身体稳定和姿势控制方面发挥着重要作用。为了将前庭信号适当地分配到脊髓运动神经元，需要考虑身体相对于头部的方位。对于不同的躯干位置，相同的前庭刺激必须激活不同的肌肉群以确保身体稳定。由于小脑蚓部及其下方的顶核（FN）可能参与此任务，因此在不同的躯干-头部位置（正中及±45度），对清醒恒河猴延髓顶核中的前庭神经元进行了正弦波前庭刺激（0.1-1.0Hz）时的记录，刺激平面为横滚和俯仰平面。根据在这些平面中测量的敏感性和相位值，计算中间平面的反应特性以及引发最佳反应的刺激方位[反应向量方位（RVO）]。在大多数神经元中，当躯干-头部位置改变时，RVO相对于头部系统地旋转，从而它们倾向于相对于躯干保持其方位。RVO处的敏感性和相位不受影响。左右FN中的神经元均呈现这种模式，且与刺激频率无关。通过线性回归分析评估，这种部分补偿性RVO偏移对躯干-头部位移反应的平均敏感性为0.59度/度（n = 73个神经元）。这些数据表明，FN神经元可能在一个比以头部为中心的参考系更接近以躯干为中心的坐标系中编码前庭信息。它们表明该核在与姿势和步态控制相关的运动程序中起着重要作用。
