408 ANATOMY OF THE CENTHAL NEETOUS SYSTEM. 



the sensory paths of second and higher order. Those of higher order lie 

 in the median fillet from the thalamus, and in the lateral fillet or the 

 fillet of the corpora quadrigemina. 



The fibers, arising in the nuclei of the posterior columns, perhaps also 

 those arising in the nuclei of the spinal cord, extend in the median line 

 within the lemniscus tract upward, and terminate in the ventral portion of 

 the thalamus opticus. The fibers from the nucleus of the trigeminus have 

 the same terminus, but they extend to the thalamus, not through the lemnis- 

 cus tract, but more dorsally and median. Besides the ending of the median 

 fillet, the tegmental radiation from the parietal lobe also ends in the region 

 of the thalamus. By it is established a connection between the sensory nerve 

 and the parietal lobe of the brain. It presents a tertiary sensory path. 



The tegmental fibers arise in the parietal lobe, possibly in the same con- 

 volutions as the pyramidal fibers, and from there extend to the posterior 

 third of the internal capsule. In this region are joined to them the visual 

 radiation of the occipital lobe and the central auditory path. A part of the 

 tegmental tract extends inward (to the right). A second portion extends to 

 and through the lentiform nucleus; another arrives at the thalamus. 



The central fibers from the nuclei of the cranial nerves, perhaps also 

 some from nuclei of the spinal nerves, ascend in the inferior or lateral fillet. 

 These end, in large part, in the ganglia of the corpora quadrigemina, and 

 in another part in the median corpus geniculatum, here principally the 

 acustieus paths of higher order. 



To these nuclei passes, principally from the white substance of the tem- 

 poral lobe, but also from more anteriorly situated cortical areas, a fibrous 

 tract, the cortical path of the acustieus, etc. 



In this manner all, the various fibers of the lemniscal tract are con- 

 nected with their centers, lying on that side which is crossed to the lem- 

 niscus. The decussation takes place in the oblongata for one portion, for 

 another in the cord itself. In the nuclei terminate always the fibers of the 

 posterior roots, or the cranial sensory nerves. 



8. A portion of the sensory nerves ends in the neighborhood of Clarke's 

 column of cells. From them arises the direct cerebellar tract, which extends 

 in the periphery of the lateral tract of the cord up to the cerebellum. 



9. Some cranial sensory nerves receive additional fibers, coming from 

 the cerebellum (direct sensory cerebellar tract). 



10. The cortical area and the central path of the sensory portion of the 

 nervus trigeminus from the cortex to the capsula are yet unknown. Follow- 

 ing pathological experitnces, its fibers must lie in the posterior third of 

 the capsule. The cortical tract of the trigeminal ends, in rabbits at least, in 

 the ventral portion of the thalamus. Leading tip to it is a large bundle 



