Role of cerebellar dorsal vermis in generation of pursuit eye movements in three dimensional space

前眼灵长类动物在前平行平面上使用平滑追踪和深度追踪来追踪在三维空间中缓慢移动的物体。3d追踪信号用额视场（FEF）表示。已有研究表明，小脑背蚓参与平滑追求和前庭-眼旋转反射（VOR）的控制。为了了解它是如何参与3d追踪信号的处理和平移VOR，我们在猴子身上进行了两个系列的研究。第一年，我们描述了追逐信号。在40%的正常追逐p细胞中观察到3d追逐信号。然而，大部分的纵向追逐p细胞（60%）要么为纵向追逐，要么为纵向追逐。此外，大多数趋同p细胞为趋同而放电，且在眼动开始前放电。背蚓注射Muscimol可降低峰值会聚眼速度和初始会聚眼速度。这些结果表明，背蚓参与了将3d追踪信号分解为额部和深度部分的过程。在第二年，我们通过被动地移动整个身体来测试右/左平移过程中正常p细胞的放电，而目标在不同的观看距离上呈现。目标要么全身移动，要么在虚拟空间中保持静止。结果与FEF追求神经元的结果进行了比较。大多数被左右翻译激活的纵向追求p细胞具有水平优先方向。相比之下，大多数偏好垂直方向或纵深方向的追求p细胞很少对左右平移做出反应。在平移过程中，目标在空间静止时，放电调制与产生的水平眼速度相关。这些结果表明，在翻译过程中，FEF追求神经元携带的信号被发送到背蚓进行进一步的处理。少

Frontal-eyed primates use both smooth-pursuit in fronto-parallel planes and pursuit-in-depth to track objects moving slowly in three-dimensional (3D) space. 3D-pursuit signals are represented in frontal eye fields (FEF). Previous studies have shown that the cerebellar dorsal vermis is involved in smooth-pursuit and the control of rotational vestibulo-ocular reflex (VOR). To understand how it is involved in processing of 3D-pursuit signals and translational VOR, we performed two series of studies in monkeys. In the first year, we characterized pursuit signals. In 40% of vermal pursuit P-cells, 3D-pursuit signals were observed. However, the majority of vermal pursuit P-cells (60%) discharged either for vergence-pursuit or frontal-pursuit. Furthermore, the majority of vergence pursuit P-cells discharged for convergence and discharged before the onset of eye movements. Muscimol infusion into the dorsal vermis resulted in a reduction of peak convergent eye velocity and of initial convergent … More eye acceleration. These results suggest involvement of the dorsal vermis in decomposition of 3D-pursuit signals into frontal and depth components. In the second year, we tested discharge of vermal P-cells during right/left translation by passively moving the whole body while a target was presented at different viewing distances. The target was moved either with the whole body or stayed stationary in virtual space. Results were compared with those obtained in FEF pursuit neurons. The majority of vermal pursuit P-cells that were activated by right/left translation had horizontal preferred directions. In contrast, the majority of pursuit P-cells that had preferred directions in vertical directions or pursuit-in-depth rarely responded to right/left translation. During target stationary in space during translation, discharge modulation was correlated with resultant horizontal eye velocity. These results suggest that signals carried by FEF pursuit neurons during whole body translation are sent to the dorsal vermis for further processing of pursuit signals during translation. Less