126 VETERINARY PHYSIOLOGY 



and there form synapses with other cells, (iii.) From these, 

 processes pass to the cells of Purkinje, round which they 

 arborise ; and (iv.) from Purkinje's cells the outgoing fibres 

 of the cerebellum pass into the white matter and so to the 

 deep nuclei, to Deiters' nuclei, and to the red nuclei (iig. 58). 



2. Connections. 



The cerebellum is connected (fig. 58) — 



1. With the Spinal Cord. 



(a) Incoming Fibres. — 1. The direct cerebellar tract 

 (p. 112) passes up in the restiform body to end chiefly in the 

 superior vermis on both sides. 2. The ventro-spinal tract 

 (p. 112) passes to the cerebellum in the superior peduncle 

 and ends in the superior vermis. 3. Fibres from the nuclei 

 of the posterior columns of the same side, and also from the 

 opposite side (p. 112), pass in the restiform body to the 

 cerebellum. 4. Fibres from the vestibular root of the eighth 

 nerve also pass to the cerebellum (fig. 58, p. 127). 



(6) Commissural Fibres. — Strong bands of fibres connect 

 the dentate nucleus and other parts of the cerebellum with 

 the inferior olivary nucleus of the opposite side. 



(c) Outgoing Fibres. — Fibres pass from the superior 

 vermis to the deep nuclei, and to Deiters' nuclei (fig. 58), 

 from which others pass down in the descending antero-lateral 

 tract of the cord. 



2. With the Cerebrum. — 1, Fibres run down in the crusta 

 of each crus from the frontal and occipital parts of the cortex 

 cerebri. They form synapses with cells in the pons, and from 

 these, fibres pass in the middle peduncle to the cerebellum. 

 2. The fibres of the superior peduncle, coming chiefly from 

 the dentate nucleus and superior vermis, cross in the middle 

 line and end — (a) partly in the red nucleus of the opposite 

 side, from which the rubro-spinal, or pre-pyramidal tract, 

 extends downward into the spinal cord ; (b) partly in the 

 thalamus opticus. From the thalamus fibres pass, some to 

 the cortex, some to the oculo-motor nuclei. 



Functionally these connections are : — 



A. Ingoing. — 1. From the spinal cord— chiefly proprio- 



