THE RHINENCEPHALON 



28l 



tract of the archipallium and serves to convey impulses from the hippocampus 

 to the hypothalamus and reticular formation of the brain stem. Through the 

 mammillary bodies olfactory impulses are relayed along the mammillothalamic 

 tract to the anterior nucleus of the thalamus, and along the mammillotegmental 

 bundle to the tegmentum of the pons and medulla oblongata (Fig. 21 1,/, g). 



The frontal olfactory projection tract takes origin from the gray matter of 

 the olfactory peduncle or trigonum olfactorium and the gyrus olfactorius later- 



Fig. 211. Diagram of the afferent and efferent paths of the mammillary body, habenular 

 ganglion, and interpeduncular ganglion: A, Medial nucleus of the mammillary body; B, C, 

 anterior nucleus of the thalamus; D, habenular ganglion; E, interpeduncular ganglion; F, dorsal 

 tegmental nucleus; J, optic chiasma; T, tuber cinereum; P, pons; a, cerebral aqueduct; b, habenular 

 commissure; c, posterior commissure; d, fasciculus retroflexus of Meynert; e, peduncle of the mam- 

 millary body;/, fasciculus mamillothalamicus; g, tegmental tract of Gudden; h, frontal olfactory 

 projection tract; i, stria medullaris thalami. The arrows indicate the direction of conduction. 

 (Cajal.) 



alis. It traverses the subthalamic region to reach the pons and medulla oblon- 

 gata. A bundle of fibers, consisting in part of collaterals, is given off from it, 

 to enter the stria medullaris thalami, which we have already traced to the habe- 

 nular ganglion (Fig. 211, h,i). 



The stria terminalis is a delicate fascicle of nerve-fibers which lies in the sulcus between 

 the thalamus and caudate nucleus (Figs. 155, 177), and accompanies the tail of the latter in 



