CHAP. XI.] FUNCTIONS OF THE CORPORA STRIATA. 347 



Corpora Striata. The anatomy of the corpora striata and optic 

 thalami, while it denotes a very intimate union between them, also 

 shews so manifest a difference in their structural characters, that it 

 cannot be doubted that they perform essentially different functions. 

 In the corpora striata the fibrous matter is arranged in distinct 

 fascicles of very different size, many, if not all of which, form a 

 special connexion with its vesicular matter. In the optic thalami, 

 on the other hand, the fibrous matter forms a very intricate inter- 

 lacement, which is equally complicated at every part. Innumerable 

 fibres pass from one to the other, and both are connected to the 

 hemispheres by extensive radiations of fibrous matter. The corpora 

 striata, however, are connected chiefly, if not solely, with the in- 

 ferior fibrous layer of each crus cerebri ; whilst the optic thalami 

 are continuous with the superior part of each crus, which is situate 

 above the locus niger. 



It will be observed, then, that while these bodies possess, as 

 a principal character in common, their extensive connexion with the 

 cerebral hemispheres, or, in other words, with the convoluted surface 

 of the brain, they are, in the most marked way, connected inferiorly 

 with separate and distinct portions of the medulla oblongata; the 

 corpora striata with the inferior fibrous planes of the crura cerebri 

 and their continuations, the anterior pyramids; and the optic 

 thalami with the olivary columns, the central and probably fun- 

 damental portions of the medulla oblongata. And this anatomical 

 fact must be taken as an additional proof of their possessing 

 separate functions. 



Now, it may be inferred, from their connexions with nerves 

 chiefly of a sensitive kind, that the olivary columns, and the optic 

 thalami, which are continuous with them, are chiefly concerned 

 in the reception of sensitive impressions, which may principally 

 have reference merely to informing the mind (so to speak), or partly 

 to the excitation of motion, as in deglutition, respiration, etc. 

 The posterior horns of the gray matter of the cord, either by their 

 direct continuity with the olivary columns, or their union with them 

 through commissural fibres, become part and parcel of a great centre 

 of sensation, whether for mental or physical actions. 



The pyramidal bodies evidently connect the gray matter of the 

 cord (its anterior horns?) with the corpora striata; and not only 

 these, but also the intervening masses of vesicular matter, such as 

 the locus niger, and the vesicular matter of the pons, and of the 

 olivary columns ; and, supposing the corpora striata to be centres 

 of volition in intimate connexion with the convoluted surface of the 



