102 LABORATORY OUTLINE OF NEUROLOGY 



fibers in the different regions. See Bailey ('16), pp. 542-549; 

 Barker ('01), Figs. 655, 656, pp. 1034,. 1035; Bolton and Moyes 

 ('12); Brodmann ('07); Campbell ('05); Cunningham ('15), 

 Fig. 574, p. 645, and also the references under Sections 114 and 

 115; Herrick ('18), Chap. XIX; Rauber-Kopsch ('12), pp. 

 175-186; ViUiger ('12), pp. 114-118. 



119. Association tracts of the sheep. Now in the sheep's 

 brain by careful teasing examine the arrangement of fibers in 

 the subcortical white matter. Only a part of these fibers are 

 to be studied at this time, and the dissection outlined in this 

 section should not be carried farther. than directed. It will 

 require but a short time. 



(1) First, along the dorsal border of the medial surface of 

 the hemisphere scrape away the gray matter covering two ad- 

 jacent gyri. This will bring into view the short associational 

 (arcuate) fibers connecting these gyri. Further teasing will 

 show that similar fibers, lying deeper in the white matter, con- 

 nect more remote gyri. 



(2) Careful dissection of the lateral surface of the hemi- 

 sphere will show that from other association areas of the cere- 

 bral cortex fibers sweep down into the pyriform (hippocampal) 

 lobe, indicating the linking-up of all association areas of the 

 neopallium with the association areas of the archipallium. . 



(3) The cingulum is a long associational tract running close 

 to the cortex of the medial surface of the hemisphere. In part 

 of its course it runs parallel with the dorsal surface of the corpus 

 callosum. It begins anteriorly in the gyrus subcallosus under 

 the rostrum of the corpus callosum, arches upward at the genu 

 of the corpus callosum, and at its posterior end passes around 

 the splenium of the callosum and then goes downward, for- 

 ward, and lateralward to the region of the hippocampal gyrus. 

 Begin its dissection above the callosum and follow it in both 

 directions to its termini. 



(4) The corpus callosum. These fibers connect all parts of 

 the neopallium of one hemisphere with those of the opposite 

 hemisphere. Break through the middle of the cingulum and 

 tease out a small part of the callosal fibers to their connection 

 with the cortex. Do not disturb the remainder of the callosum 

 at this time. 



