

the thalamus. I'rom the thalamus the projection fibres of this system pass in the 

 general thalamO-OOrtical path to the soma'sthetic area. 



The descending projection fibres arise as outgrowths of the pyramidal cells of 

 the respective regions () f the cerebral cortex, in which the ascending fibres terminate. 

 The principal groups of these arc as follows: 



(1) The pyramidal fasciculi. The fibres of this group arise from the plant 

 pyramidal cells of the posterior central gyri and anterior end of the para central lobule 



!''. ; >l ' I>" MiUVMS SIIOWIV,; I I IK < ll.M.KM. SKN-MllY AM) AssnUATION AlCEAS OF THE CONVEX 



AMI MI.DIAL SiuiA'i'> oi < KHKHKAI. 1 1 i:\i isi'ii HUE. (From .Spaltcholz, aft cr I- livhsig.) 



PARIETAL \8SOCIA 



- <- 



FRONTAL 

 ASSOCIA- 

 TION 



CENTRE 



OCCIPlTO-TKMI'(li:.( I, 



AStMCl.ll l"\ i , 



AflitTORY AREA 



SOMsESTJIETIC .I/.'/. I 



PARIETAL AWH'l.l- 



i ni\ < /..v //./: 



FROXTM, 



ASSOCIA l'l<>.\ 



I I-:.\TRK 



(parts of the sonuesthetic area). They descend through the middle part of the rorona 



radiata. the genii and anterior two-thirds of the occipital portion of the internal 



capsule, into the basis of the peduncle, thence through the cerehral peduncle and 



pyramid of the medulla, and decussate to pass down the spinal cord to terminate 



about t he cells of t he vent nil horn the origin of the motor roots of t he spinal nerves. 



(iM The pyramidal fibres to the nuclei of origin of the motor cranial nerves, 



the 'accessory lemniscus' of Hechterew. These have the same oritrin and practically 



55 



