THE CENTRAL NERVOUS SYSTEM. 73 



divisions running in the direction of the surface fold and thus crossing 

 the dendrons of the cells of Purkinje at right angles. Afferent fibres 

 from the white matter arborise round the cells of the granular layer, 

 and are called moss-fibres because of the appearance of their 

 terminations. 



The outer layer of grey matter, or molecular layer, contains the 

 dendrons of Purkinje's cells, the axons of the small cells of the internal 

 layer, scattered nerve cells, and the terminations of afferent fibres from 

 the white matter. The nerve cells of this layer are called basket cells, 

 from the fact that their axons and the collaterals from the axons 

 terminate round the cytons of the cells of Purkinje in a basket-like 

 fashion. The afferent nerve fibres which reach the molecular layer 

 arborise in apposition with the dendrons of the cells of Purkinje, and are 

 hence known as climbing or tendril fibres. The Purkinje cells receive, 

 therefore, three sets of afferent impulses, namely, (1) from the axons of 

 the cells of the granular layer,, (2) from the basket cells, and (3) from 

 the tendril fibres. 



The axons of the cells of Purkinje end in the nucleus dentatus, 

 from which the impulses they transmit are passed on by other neurons. 



The superior peduncles (brachia conjunctiva) pass to the mid-brain 

 and run under the inferior colliculi. There the fibres of each cross the 

 middle line and divide into ascending and descending branches. The 

 ascending divisions end in the thalamus, the red nucleus, and the nuclei 

 of the oculo-motor nerves. The descending divisions are believed to 

 reach the anterior columns of the spinal cord. The brachia conjunctiva 

 also convey the fibres of the antero-lateral ascending tract of the same 

 side to the vermis of the cerebellum. 



The brachia pontis form part of the connecting path between the 

 cerebral hemispheres and the hemispheres of the cerebellum, the 

 connection being a crossed one. 



The restiform bodies contain both efferent and afferent fibres. The 

 efferent fibres run from the nucleus fastigii and dentate nucleus to the 

 nucleus of Deiters and the medulla oblongata. The afferent fibres 

 are (1) the direct cerebellar tract from the same side of the spinal 

 cord to the vermis ; (2) fibres from the medulla oblongata, (a) from 

 the nucleus gracilis and nucleus cuneatus of the same and the opposite 

 sides, (b) from the olivary nucleus of the opposite side, and (c) from 

 the formatio reticularis of both sides ; (3) fibres from the chief vesti- 

 bular nucleus and from Deiters' nucleus. 



The cerebellum thus receives afferent fibres from the spinal cord, 

 some direct through the restiform body, others by way of the superior 

 peduncles, and other fibres which convey impulses from the spinal cord 



