Manzoni D, Pompeiano O, Andre P
Dipartimento di Fisiologia e Biochimica, Università di Pisa, Via S. Zeno 31, I-56127 Pisa, Italy.
Pflugers Arch. 1998 Apr;435(5):617-30. doi: 10.1007/s004240050562.
Convergence of spatially oriented vestibular and neck signals within the cerebellar anterior vermis in decerebrate cats was studied by recording the simple spike discharge of Purkinje (P) cells during wobble either of the whole animal (vestibular input) or of the body under a fixed head (neck input) at 0.156 Hz, 5 degrees and 2.5 degrees , respectively. Both clockwise (CW) and counterclockwise (CCW) rotations were performed. Units that had equal response amplitudes to CW and CCW rotations (narrowly tuned neurons) were described by a single vector (Smax), characterized by a gain, a direction and a temporal phase. Units with different response amplitudes to CW and CCW rotation (broadly tuned neurons) were described by two vectors (Smax and Smin). In addition to these bidirectional units, there were also unidirectional units which responded either to CW or CCW rotation; in these cases the gain of Smax equals that of Smin. On the whole, 77% and 63% of the P cells responding to vestibular and neck stimulation, respectively, showed a bidirectional broadly tuned or unidirectional behavior. These response patterns were attributed to the convergence of signals with different spatial and temporal properties. About 50% of the P cells from which recordings were made responded to stimulation of both sensory systems. However, the gains of the Smax vectors of the neck responses were much greater than those of the vestibular responses, at least for small amplitudes of rotation, and were positively correlated with them. Usually the differences in the orientation components of the neck and vestibular Smax vectors were larger, while the differences in temporal phases were smaller than 90 degrees . These findings suggest that periodic changes in the phase difference and gain ratio of the neck to the vestibular response may occur during dynamic displacement of the head over the body, depending on the stimulus direction. As a result of these data, the P cells of the cerebellar vermis are expected to show prominent responses to head rotation, which could affect the spatially organized postural responses by utilizing vestibular and reticular targets.
通过在去大脑猫中记录浦肯野（P）细胞的简单锋电位发放，研究了小脑前蚓部内空间定向的前庭信号和颈部信号的汇聚情况。在动物整体摆动（前庭输入）或头部固定时身体摆动（颈部输入）过程中，分别以0.156 Hz、5度和2.5度的频率进行记录。同时进行顺时针（CW）和逆时针（CCW）旋转。对CW和CCW旋转具有相等反应幅度的单位（窄调谐神经元）由单个向量（Smax）描述，其特征为增益、方向和时间相位。对CW和CCW旋转具有不同反应幅度的单位（宽调谐神经元）由两个向量（Smax和Smin）描述。除了这些双向单位外，还有单向单位，它们对CW或CCW旋转有反应；在这些情况下，Smax的增益等于Smin的增益。总体而言，分别对前庭和颈部刺激有反应的P细胞中，77%和63%表现出双向宽调谐或单向行为。这些反应模式归因于具有不同空间和时间特性的信号的汇聚。约50%进行记录的P细胞对两个感觉系统的刺激都有反应。然而，至少对于小幅度旋转，颈部反应的Smax向量的增益远大于前庭反应的增益，且与前庭反应的增益呈正相关。通常，颈部和前庭Smax向量的方向分量差异较大，而时间相位差异小于90度。这些发现表明，在头部相对于身体的动态位移过程中，根据刺激方向，颈部与前庭反应的相位差和增益比可能会发生周期性变化。基于这些数据，预计小脑蚓部的P细胞对头部旋转会表现出显著反应，这可能通过利用前庭和网状靶点来影响空间组织的姿势反应。
