220 



INTRODUCTION TO NEUROLOGY 



cerebral hemispheres (see the works by Edinger cited at the end 

 of this chapter). 



From these nuclei of the olfactory area fiber tracts of the third 

 order pass to the mammillary bodies of the hypothalamus and 

 to the habenular bodies of the epithalamus, from both of which, 

 after another synapse, tracts lead downward into the motor 



com. post, 

 hab. 

 f.reth 

 nanT. 

 str. med. 

 tr. mamTh. 

 Tr. olf. fegm 



form bulb. 



TfrolT.hyptKS 



^com.ont. 

 ^n. pop 



Fig. 106. Diagram of some of the olfactory tracts in the brain of the 

 rat. The chief connections of the medial and intermediate olfactory tracts 

 are indicated; those of the lateral olfactory tract are omitted: c.mam., 

 corpus mamillare; col. forn., columna fornicis; com. ant., commissura an- 

 terior; com. hip., commissura hippocampi; com. post., commissura posterior; 

 form, bulb., formatio bulbaris; f.retr., fasciculus retroflexus of Meynert; 

 hob., habenula; h.pc., hippocampus precommissuralis; h.sc., hippocampus 

 supracommissuralis; n. ant., nucleus anterior thalami; n. olf. ant., nucleus 

 olfactorius anterior; n. pop., nucleus preopticus (ganglion opticum basale); 

 S, septum; str. med., stria medullaris thalami; tr. mam. th., tractus mamillo- 

 thalamicus (Vicq d'Azyri) ; tr. olf. hypth., tractus olfacto-hypothalamicus, or 

 basal olfactory tract; tr. olf. tegm., tractus olf acto-tegmentalis; tub. f. dent., 

 tuberculum fasciae dentatse (hippocampus postcommissuralis) ; tub. olf., 

 tuberculum olfacfcorium. 



centers of the midbrain in the cerebral peduncle. The path from 

 the mammillary body is the tractus mamillo-peduncularis (Figs. 

 75, 78, 106). The path from the habenular body is the tractus 

 habenulo-peduncularis (fasciculus retroflexus B. N. A., or Mey- 

 nert's bundle Fig. 106). The mammillary body also sends a 

 tract into the anterior nucleus of the thalamus, the tractus mam- 

 illo-thalamicus (fasciculus thalamo-mamillaris B. N. A., or tract 



