COURSE OF THE MOTOR AND SENSORY TRACTS. 



745. 



through the upper portion of the crusta of the cerebral peduncle downward into 

 the medulla oblongata, or only to the pons according to Flechsig. In a similar 

 manner a bundle passes from the optic thalamus (7) and from the quadrigeminate 

 bodies (6, 6) that descends through the tegmentum (H) of the cerebral peduncle. 

 Both groups of fibers, those in the crusta as well as those in the tegmentum, 

 unite below in the spinal cord. '_, s v 



h.W. 



FIG. 254. I. Diagrammatic Representation of the Structure of the Brain: C, C, cerebral cortex; C. s, striate 

 body; N.I, lenticular nucleus; T.o, optic thalamus; V, quadrigeminate bodies; P, cerebral peduncle; H, 

 tegmentum; p, crusta; i, i, fibers of the corona radiata to the striate body; 2, 2, to the lenticular nucleus; 

 3, 3, to the optic thalamus; 4, 4, to the quadrigeminate bodies; 5. direct fibers to the cerebral cortex; 6, 6, 

 fibers from the quadrigeminate bodies to the tegmentum; 7, fibers from the optic thalamus to the tegmentum; 

 m, their further course; 8, 8, fibers from the striate body and the lenticular nucleus to the crusta of the cere- 

 bral peduncle; M, their further course; S, S, course of the sensory fibers; R, transverse section of the spinal 

 cord; v.W, anterior and, h.W, posterior root; a, a, association-fibers; c, c, commissural fibers. II. Trans- 

 verse Section through the Posterior Pair of the Quadrigeminate Bodies and the Cerebral Peduncles of Man 

 (after Meynert): p, Crusta of the peduncle; s, substantia nigra; v, the quadrigeminate bodies with the trans- 

 verse section of the aqueduct. III. A Like Section from the Dog. IV. From the Ape. V. From the Guinea-pig. 



According to Wernicke the lenticular and caudate nuclei are not parts of the 

 cerebrum into which fibers of the corona radiata from the cortex enter, but they 

 are independent structures analogous to the cortex, from which fibers originate. 

 These fibers later on reach the tegmentum, where they lie side by side with the 

 fibers derived from the optic thalami and the quadrigeminate bodies. 



