THE NERVOUS SYSTEM 541 



part of the pes, those from the frontal region pass down in the anterior 

 Hmb of the internal capsule and mesial part of the pes. (4) Pallio- 

 tectal fibres to the midbrain roof. (5) Fibres to the substantia 

 nigra and corpus subthalamicum. (6) Fibres to the red nucleus. 

 (7) Pallio-thalamic fibres (see p. 529). (8) Fibres, or collaterals, 

 to the corpora striata. (Fig. 360.) 



The crossed association fibres of the neopallium (corpus callosum) 

 connect principally corresponding parts of the hemispheres. The 

 long uncrossed association fibres (furthest from the gray matter) 

 form certain more or less well-defined bundles among which are the 

 following: (i) The cingulum, a longitudinal bundle near the corpus 

 callosum; also contains projection fibres and belongs to the olfactory 

 part of the brain as well as to the neopallium. (2) The superior 

 longitudinal fasciculus or fasciculus arcuatus; connects frontal with 

 occipital and part of temporal lobes. (3) The inferior longitudinal 

 bundle connecting temporal and occipital lobes. It may, however, 

 be a projection bundle. (4) The uncinate fasciculus connecting 

 frontal and temporal lobes. (5) The perpendicular fasciculus of 

 Wernicke connecting inferior parietal and fusiform lobules. Pro- 

 jection fibres may form portions of these bundles. 



Besides the above long association fibres there are shorter 

 association fibres nearer the gray matter which connect adjoining 

 convolutions (fibrae propriae of Meynert). 



PRACTICAL STUDY 



13. Transverse Section through the Cerebral Hemispheres, Corpora Striata 



and Thalamus (Fig. 361) 



First distinguish in general (i) the pallium, its cortex and white matter, (2) 

 the corpus striatum and its divisions, i.e., the caudate nucleus and the lenticular 

 nucleus, the latter being subdivided into the putamen and globus paUidus and 

 (3) the thalamus and other structures of the interbrain. 



lamina medullaris interna nuclei lenticularis; mp and ms, sulcus circularis (Reili); NA, 

 nucleus amygdaliformis; Nc, nucleus caudatus; OpR, operculum; oti, sulcus occipitotem- 

 poralis inferior; pCR, pes coronEe radiatae; PiTlt, pedunculus inferior thalami; prs, 

 sulcus prsecentralis; Pu, putamen; rcc, stratum reticulum coronse radiatae;i?o/>, radiatio 

 optica; S, fissura Sylvii (posterior branch); Sgc, substantia grisea centralis; sM, sulcus 

 Monroi; Sge, substantia grisea subependymalis; ssc, stratum subcallosum: Strz, stratum 

 zonale thalami; Tbc, tuber cinereum; Th, thalamus opticus; ti, sulcus temporalis in- 

 ferior; Ti, gjTus temporalis inferior; tin, sulcus temporalis medius; Tm, gyrus temporahs 

 medius; ts, sulcus temporahs superior; Ts, gyrus temporahs superior; Tte, taenia tecta; 

 U, uncus; VI, ventriculus lateralis; Vli, ventriculus lateraHs (cornu inferius); vst, 

 pedunculus anterior thalami; A', pedunculus putaminis; CM, Commissure of Meynert. 



