CENTERS OF CORRELATION. 



259 



is by no means situated in the ventral part of the thalamus (as often 

 stated) but lies mesial to the corpus geniculatum laterale in the 

 dorsal half of the thalamus (Fig. 128). It would be better to call 

 it as Cajal does the sensory nucleus of the thalamus, especially 

 as the term nucleus ventraHs is used for a different center in fishes. 

 From this sensory nucleus impulses are forwarded to the cerebral 

 cortex and descending fibers from the cortex also end in this 

 nucleus. In the cat (Tschermak) a part of the fibers of the me- 



Fig. 129. — Transverse section of the dorso-mesial portion of the posterior corpus 

 quadrigeminum of the newborn dog. From Cajal (Textura, etc.). A, peripheral 

 fiber layer; B, cells of the second layer; C, stellate and fusiform cells of the third 

 layer; D, fibro-cellular layer; E, central gray matter; i?, commissure; F, ple.xus 

 of second and third layers. 



dial lemniscus are found by the degeneration method going 

 through the thalamus to reach the cortex directly. There is some 

 evidence that such bulbo-palHal fibers exist also in man. In view 

 of the ending of secondary cutaneous fibers in the midbrain in 

 lower vertebrate sit may be expected that some of the fibers of the 



