Lau K L, Glover R G, Linkenhoker B, Wylie D R
Department of Psychology, University of Alberta, Edmonton, Canada.
Neuroscience. 1998 Jul;85(2):605-14. doi: 10.1016/s0306-4522(97)00620-9.
Previous electrophysiological studies in pigeons have shown that the vestibulocerebellum can be divided into two parasagittal zones based on responses to optic flow stimuli. The medial zone responds best to optic flow resulting from self-translation, whereas the lateral zone responds best to optic flow resulting from self-rotation. This information arrives from the retina via a projection from the accessory optic system to the medial column of the inferior olive. In this study we investigated inferior olive projections to translational and rotational zones of the vestibulocerebellum using the retrograde tracer cholera toxin subunit B. Extracellular recordings of Purkinje cell activity (complex spikes) in response to large-field visual stimuli were used to identify the injection sites. We found a distinct segregation of inferior olive cells projecting to translational and rotational zones of the vestibulocerebellum. Translation zone injections resulted in retrogradely labeled cells in the ventrolateral area of the medial column, whereas rotation zone injections resulted in retrogradely labeled cells in the dorsomedial region of the medial column. Motion of any object through space, including self-motion of organisms, can be described with reference to translation and rotation in three-dimensional space. Our results show that, in pigeons, the brainstem visual systems responsible for detecting optic flow are segregated into channels responsible for the analysis of translational and rotational optic flow in the inferior olive, which is only two synapses from the retina.
先前对鸽子的电生理研究表明，基于对视觉流刺激的反应，前庭小脑可分为两个矢旁区。内侧区对自身平移产生的视觉流反应最佳，而外侧区对自身旋转产生的视觉流反应最佳。该信息通过副视系统从视网膜投射到下橄榄核的内侧柱。在本研究中，我们使用逆行示踪剂霍乱毒素B亚单位研究了下橄榄核向前庭小脑平移区和旋转区的投射。利用浦肯野细胞对大视野视觉刺激反应的细胞外记录（复合锋电位）来确定注射部位。我们发现投射到前庭小脑平移区和旋转区的下橄榄核细胞有明显的分隔。平移区注射导致内侧柱腹外侧区域出现逆行标记细胞，而旋转区注射导致内侧柱背内侧区域出现逆行标记细胞。任何物体在空间中的运动，包括生物体的自身运动，都可以参照三维空间中的平移和旋转来描述。我们的结果表明，在鸽子中，负责检测视觉流的脑干视觉系统被分隔成负责在下橄榄核中分析平移和旋转视觉流的通道，而下橄榄核与视网膜仅相隔两个突触。
