FUNCTIONS OF THE BASAL GANGLIA. 



483 



side. If the irritation be continued, motor reactions are exhibited 

 in various parts of the body. Destruction of the pregeminum in both 

 monkeys and rabbits is followed by blindness, dilatation and immo- 

 bility of the pupils, with marked disturbance of equilibrium and 

 locomotion (Ferrier). 



From the anatomic relation of the posterior quadrigeminal body 

 (the-postgeminum) to the lateral fillet, the basal tract for hearing, 

 the inference may be drawn that it is in some way connected with the 

 auditory process. 



Stimulation of the postgeminum gives rise to cries and various 

 forms of vocalization. 

 Pathologic states of this 

 body are also attended by 

 impairment of hearing 

 and disorders of the 

 equilibrium. 



From the foregoing 

 facts it is probable that 

 the corpora quadrigem- 

 ina are associated with 

 station and locomotion. 

 Ferrier assumes that in 

 these bodies "sensory 

 impressions, retinal and 

 others, are coordinated 

 with adaptive motor re- 



actions such as are in- 

 volved in equilibration 

 and locomotion." 



The Corpora Striata. 

 -The relation of these 

 bodies to the pyramidal 

 motor tract would indi- 

 cate that - they are in 

 some way connected with 

 motor activities. Their 



FIG. 218. HORIZONTAL SECTION or THE INTERNAL 

 CAPSULE SHOWING THE POSITION AND RELA- 

 TION OF THE MOTOR TRACTS FOR THE EYE, 

 HEAD (Hd.), TONGUE (Tg.), MOUTH (Mth.), 

 SHOULDER (Shi.), ELBOW (Elb.), DIGITS OF 

 HAND (Dig.), ABDOMEN (Abd.), HIP, KNEE 

 (Kn.), DIGITS OF FOOT (Dig.). S. Sensor 

 tract. O. T. Optic tract. A. T. Auditory 

 tract, i. Caudate nucleus. 2. Anterior seg- 

 ment of internal capsule. 3. External capsule. 

 4. Island of Reil. 5. Lenticular nucleus. 6. 

 Claustrum. 7. Posterior segment of internal 

 capsule. (Modified from Landois.) 



function, however, is ob- 

 scure. While stimulation of one corpus produces convulsion of the 

 muscles of the opposite side of the body, and destruction gives rise 

 to paralysis of the corresponding muscles, it is difficult, owing to the 

 intimate association of the white and the gray matter, to state to 

 which the phenomena are to be attributed. The evidence at hand 

 points to the conclusion that if a lesion is limited to the gray matter 

 the paralysis which might result would be but temporary and of short 

 duration. The pathologic evidence is of a similar character. Gowers 



