THE CEREBRUM 



165 



All of the thalamic nuclei of the lateral group (the neothala- 

 mus) are connected by important systems of fibers with the 

 cerebral cortex, these fibers running both to and from the cortex 

 (Fig. 77). These are called sensory projection fibers and all 

 pass through or near the internal capsule of the corpus striatum 

 (p. 169). As we have just seen, the nuclei of the lateral group 

 receive special systems of somatic sensory fibers optic, acous- 

 tic, and the general cutaneous and deep sensibility complex of 



Corpus callosum x 



Fimbria* X ' 



x 

 Nucleus anterior ^ * 



Tr. mamillo-thalamicus^ x 



Nucleus lateral is s v 

 MetathalamuSv 



Habenula > 

 Fasc. ret.- 

 Nuc. post.. 

 Nuc. ven \ - 



Subthal. 

 Nuc. ruber 



Lemn. V 



Br. conj.__ __ 



3. nigra 



Lemn. med. 



Tr. th.-pe<L 



Fig. 78. Diagram of the nuclei of the diencephalon and some of their 

 functional connections as seen in parasagittal section taken close to the 

 median plane. The epithalamus and the hypothalamus are stippled. 

 Br.conj., Brachium conjunctivum; Fasc.ret., fasciculus retroflexus; Lemn. 

 med., lemniscus median's; Lemn.V., lemniscus trigemini; Nuc.post., nucleus 

 posterior thalami; Nuc.ven., nucleus ventralis thalami; Subthal., subthala- 

 mus; S.nigra, substantia nigra; Tr.th.-ped., tractus thalamo-peduncularis. 



the spinal, trigeminal, and medial lemnisci. The elements of 

 the latter complex (comprising touch, temperature, pain, general 

 proprioceptive sensibility, spatial localization, etc., termed as a 

 whole the somesthetic group) are no doubt separately represented 

 in the thalamus, but the analysis of their respective thalamic 

 centers has not yet been completely effected. Each of the chief 

 functional regions of the neothalamus which have just been 

 enumerated is connected by its own system of projection fibers 



Stria medullaris 

 Columna fornicis 

 Commissure anterior 

 Lamina tcnninalis 

 Area olfactoria medialia 

 Corpus mamillare 

 Nervus opticus 

 Tractus olfactorius 



