

IE FORE-BRAIN OR PROSENCEPHALON 



835 



a yellowish tint, and together constitute the globus pallidus; all three are marked by 

 fine radiating white fibers, which are most distinct in the putamen (Fig. 744) . 



The gray substance of the corpus striatum is traversed by nerve fibers, some 

 of which originate in it. The cells are multipolar, both large and small; those of 

 the lentiform nucleus contain yellow pigment. The caudate and lentiform nuclei 

 are not only directly continuous with each other anteriorly, but are connected to 

 each other by numerous fibers. The corpus striatum is also connected: (1) to the 

 cerebral cortex, by what are termed the corticostriate fibers; (2) to the thalamus, 

 by fibers which pass through the internal capsule, and by a strand named the 

 a lentif ormis ; (3) to the cerebral peduncle, by fibers which leave the lower 



pect of the caudate and lentiform nuclei. 



Superior frontal gyrus 



Middle frontal 

 gyrus 



Corpus callosum 



Anterior cornit 



Septum pellucidum 



Caudate nucleus 



Internal capsule 



Lentiform nucleus 



Sulcus olfactorius 



^^g^^. 



Insula 



Temporal lobe 

 Inferior frontal gyrus 



FIG. 743. Coronal section through anterior cornua of lateral ventricles. 



The claustnun (Figs. 742, 744) is a thin layer of gray substance, situated on the 

 lateral surface of the external capsule. Its transverse section is triangular, with 

 the apex directed upward. Its medial surface, contiguous to the external capsule, 

 is smooth, but its lateral surface presents ridges and furrows corresponding with 

 the gyri and sulci of the insula, with which it is in close relationship. The claustrum 

 is regarded as a detached portion of the gray substance of the insula, from which 

 it is separated by a layer of white fibers, the capsula extrema (band of Baillarger). 

 Its cells are small and spindle-shaped, and contain yellow pigment; they are similar 

 to those of the deepest layer of the cortex. 



The nucleus amygdalae (amygdala) (Fig. 741), is an ovoid gray mass, situated at the 

 lower end of the roof of the inferior cornu. It is merely a localized thickening of the 



