AFFERENT, OR SENSORY PATHS. 381 



medial fillet and run to the thalamus, so muscular and tactile 

 sensations transmitted by those cerebral nerves to their nuclei 

 in the medulla and pons, are carried by the medial fillet to the 

 lateral nucleus of the thalamus on the opposite side. The cortical 

 fillet conducts them to the lower portion of the posterior central 

 gyms in the somaesthetic area. 



H. PATHS CARRYING IMPULSES OF THE MUSCULAR 

 AND TACTILE SENSES, CHIEFLY FROM VISCERA (?). 



Through (Posterior) Cerebello-spinal Tract (Direct Cere- 

 bellar) (Fig. 107). The column of cell-bodies, forming the nucleus 

 dorsalis (Clarki), receives impulses concerning equilibrium (?) 

 from the posterior roots of the spinal nerves and transmits them 

 at once to the (posterior) cerebello-spinal tract, through which 

 they ascend along the dorso-lateral surface of the cord, along the 

 posterior surface and through the restiform body of the medulla 

 to the cortex of the superior worm of the cerebellum. To a 

 smaU extent they cross in the worm to the opposite side. These 

 impulses probably excite, within the cerebellar cortex, impulses 

 of coordination and equilibrium which traverse the descending 

 anterior cerebello-spinal tract to the gray crescent of the cord, 

 and are transmitted to the motor neurones of the anterior columna. 

 The motor neurones conduct the impulses to the muscles. From 

 the cerebellar cortex the journey to the cerebrum is completed in 

 four stages, as already described, namely: Nucleus dentatus, 

 opposite red nucleus, thalamus and some part of the cerebral 

 cortex, probably the middle and inferior temporal gyri. 



Probably the vagus nerve conducts impulses of similar nature 

 from the viscera to its terminal nucleus; but, if so, their path 

 from the terminal nucleus is not certainly known. 



PATHS CONVEYING PAIN, TEMPERATURE AND TAC- 

 TILE IMPRESSIONS. SPINAL AND CEREBRAL. 



Through Spino-thalamic and Ascending Anterior Cere- 

 bello-spinal Tract (Fig. 108). In the spinal cord, medulla and 

 pons these constitute one tract, commonly called Gowers's tract. 

 They separate just below the isthmus, whence the spino-thalamic 

 tract continues to the thalamus and the other turns back to the 

 cerebellum. They appear to form the only paths for pain and 



