96 LABORATORY OUTLINE OF NEUROLOGY 



diencephalon, and telencephalon. Like the rhombencephalon, 

 the cerebrum includes a stem portion, or segmental apparatus, 

 and a suprasegmental apparatus (the cerebral cortex). 



The brain stem, as a whole, is devoted to the simpler reflex and 

 instinctive activities, while the cerebral cortex serves the higher 

 functions of association. The cerebral hemispheres make up 

 the greater part of the telencephalon. Each cerebral hemisphere 

 comprises cortical and basal or stem portions. The latter 

 includes the olfactory bulb, anterior perforated space (tuber- 

 culum olfactorium), septum, corpus striatum, and some other 

 parts. The cortex (pallium) has two great subdivisions, 

 archipallium (old cortex) and neopallium (new cortex). The 

 archipallium attains its maximum development in lower mam- 

 mals and is chiefly devoted to olfactory correlations. It com- 

 prises the hippocampus and part of the gyrus hippocampi 

 (hippocampal lobe or pyriform lobe). The neopallium is non- 

 olfactory cortex and attains its highest development in the 

 human brain. In the sheep also it is more extensive than the 

 archipallium, occupying the convex dorsal surface of the hemi- 

 sphere. 



113. The midbrain and thalamus. — On the median surfaces 

 of the sheep and human brains review the aqueduct of Sylvius, 

 the boundaries of the third ventricle, and the other landmarks 

 in the midbrain and thalamus (see Section 59) . On the lateral 

 aspect of the specimens locate the colliculus inferior, colliculus 

 superior, corpus geniculatum mediale, corpus geniculatum 

 laterale (medial, or internal, and lateral, or external, geniculate 

 bodies), and the pulvinar. In the sheep the lateral geniculate 

 body is not clearly separate from the pulvinar, forming the most 

 ventral part of the eminence which includes both of these 

 structures. The medial geniculate body (Fig. 12) is connected 

 with the inferior colliculus by a clearly defined ridge, the 

 peduncle of the inferior colliculus (brachium quadrigeminum 

 inferius). The connection of the lateral lemniscus with the 

 inferior colliculus and medial geniculate body has already been 

 mentioned (Sections 81, 82, and 106). The optic tract is 

 similarly related to the superior colliculus, lateral geniculate 

 body, and pulvinar; but the further dissection of this region to 



