S7 o TEXT-BOOK OF PHYSIOLOGY 



The cells of the post-geniculum give origin to axons which pass upward, 

 forward, and outward, enter the internal capsule, and pass by way of the 

 auditory tract to the cortex of the temporo-sphenoidal region of the cerebrum. 

 Many of the fibers of the lateral fillet, a portion of the auditory tract, termi- 

 nate in brush-like expansions around these same cells. There is thus es- 

 tablished a connected pathway between the cochlea and the temporo-sphe- 

 noidal cortex. The cells of the temporal cortex, however, send axons in the 

 reverse direction by way of the auditory tract to the cells of the post-geniculum. 

 There is thus established a double communication between the occipital 

 and temporal regions of the cerebral cortex, and the pre-geniculum and post- 

 geniculum bodies respectively. 



THE BASAL GANGLIA : THE CORPORA STRIATA AND OPTIC 



THALAMI 



The basal ganglia are collections of ganglionic matter, situated at the 

 base of the cerebrum along the course of the nerve-fibers that pass to and 



FIG. 236. CORPORA STRIATA, OPTIC THALAMI, CORPORA QUADRIGEMINA, CEREBELLUM AND 

 ASSOCIATED STRUCTURES, i, Corpora quadrigemina; 2, valve of Vieussens; 3, pre-peduncle; 

 4, upper part of medi-peduncle; 5, upper part of crus; 6, lateral fillet; 7, band of Reil; 8 post- 

 brachium; 9, frenulum; 10, gray matter of valve of Vieussens; n, medi-commissure; 12, pre-com- 

 missure; 13, 14, center of cerebellum; 15, post-commissure; 16, peduncles of the pineal gland; 17, 

 pineal gland; 18, 19, posterior and anterior tubercles of the thalamus; 20, teniasemicircularis; 21, 

 vessels of the corpus striatum; 22, fornicolumn; 23, corpus striatum; 24, septum lucidum. 

 (Sappey.) 



from its cortical expansion. Among these ganglia the more important are 

 the corpora striata and the optic thalami. They are made visible upon 

 removal of the cerebrum. The general relations of these ganglia are shown 

 in Fig. 236. 



The corpus striatum, the more anterior of the two, is an ovoid col- 



