functions of the Basal Ganglia. 635 



directly to the anterior p}'ramids of the medulla oblongata, and so on 

 down the cord, showing the cortex to be independent of the corpora 

 striata. It would appear, then, that the corpora striata, in conjunction 

 with the optic thalamus, and perhaps other sensory ganglia, constitutes 

 a complete brain, just as the sensory and motor ganglia of the cortex 



FIG. 349. Vertical transverse sec- 

 tion through the brain of a Doa, on 

 a level with the corpora mammil- 

 laria. (After Camrille & Duret, 

 Ferrier.) 



O, 0. Optic Thai ami. 



8, S. Caudate Nuclei of the Cor- 

 pora Striata. 



L, L. The Lenticular Nuclei of the 

 Corpora Striata. 



P, P. Internal Capsule, or pedun- 

 cular expansion. 



A, A. The hippocampi. 



X. Section of the posterior part 

 of the peduncular expansion, caus- 

 ing 1 hemianesthesia (loss of sensa- 

 tion ) on opposite side of the body 

 in Dog or Man. 



do, though, of course, of a 

 far less comprehensive kind. 



A 'A 



FIG. 349. 



A mechanical irritation of the corpora 

 striata does not produce pain or muscular movement, but when they are 

 stimulated by the galvanic current, normal muscular action is the re- 

 sult. If one of the intraventricular ganglions, the nucleus caudatus, 

 is electrically irritated, tonic contraction of all the muscles on the oppo- 



FIG. 350. Horizontal section of left hemisphere of 

 Monkey, on a level ivith the anterior commissure. 

 ( Natural size.) ( Ferrier.) 



ac Anterior commissure. 



ca. Cornu ammonia, or hippocampus major. 



cl. Claustrum. 



c<?. Corpora Quadrigemina. 



ec. External Capsule. 



ic. Internal 



/#. Island of Reil. 



/.Anterior pillar of Fornix. 



/'.Ascending fibres vicq d'Azyr's bundle. 



Mf. Meynerts fasciculus. 



/s. Fissure of Sylvius. 



nc. Caudate Nucleus of Corpus Striatum. 



nl. Lenticular 



or. Optic radiations. 



P. Pulvinar. 



p. Posterior Commissure. 



site side, is the result. The experiments 

 appear to prove that the motor connections 

 of the corpora striata are exclusively with 

 the decussating strands of the spinal axis, 

 so that all its motor action is crossed. 



Destructive lesions in the region of the cor- 

 pus striatum, cause paralysis of motion on the opposite side of the 

 body, but sensation is not affected. It is evident, however, that the 

 functions of the corpus striatum, in regard to the motion of the limbs, 

 may be assumed entirely by the cortex of the hemispheres, because as 

 long as the cortex and its efferent connections, by way of the anterior 

 two-thirds of the internal capsule, remain unbroken, lesions of the cor- 



FIG. 360. 



