ORIGIN OF CELLS OF SPINOCEREBELLAR TRACTS IN THE RABBIT, STUDIED WITH THE METHOD OF RETROGRADE TRANSPORT OF HORSERADISH PEROXIDASE / 解剖学报

ABSTRACT

Horseradish peroxidase (HRP) was injected unilaterally or bilaterally into the cerebellum of 11 rabbits in order to trace the distribution of labeled neurons in the whole length of the spinal cord. To investigate the ascending side of the axons, hemisections were made unilaterally in the lower thoracic cord of 4 rabbits before injection. The distribution of labeled spinocerebellar tract neurons was rather wide. Neurons in the cervical segments were located in (1) the central cervical nucleus (CCN) in Q_(1-4), (2) the medial part of lamina VI in C_2-T_1, (3) the central part of lamina VII in C_(4-8) and (4) lamina IV-V in C_(5-8). The labeled neurons located in segments caudal to thoracic cord could be divided into two groups. Neurons of the uncrossed tract were located in (1) Clarke's column in T_2-L_4, (2) laminae IV-VI in T_2-L_6. Neurons of the crossed tract were found in (1) the spinal border cells (SBC)in L_(3-6), (2) the medial part of the lamina VII in segments caudal to L_6, (3) lamina V in the sacrococcygeal cord and (4) laminae VII-VIII in the sacrococcygeal cord. The present study suggests that the location and fiber course of the spinocerebellar neurons in the rabbit are quite the same as those in the cat. These results should form a basis for further anatomical and physiological studies of spinocerebellar system in the rabbit.