GANGLIONAR GRAY MATTER. 21 7 



cerebelli, up to the somagsthetic area (Fig. 54). Interruption of 

 the cortical fillet stops all common sensory impulses tactile, pain 

 and temperature impulses, and impulses of the muscular sense. 



(5) Radiatio Occipito-thalamica (Gratioleti). A large pencil of 

 fibers, the optic, or occipito-thaldmic radiation (Fig. 70) passes 

 from the lateral geniculate body and the pulvinar through the in- 

 ternal capsule to the visual centers in the occipital lobe. A num- 

 ber of fibers in the occipito-thalamic radiation are corticifugal and 

 end in the superior quadrigeminal colliculus, though many are 

 probably relayed in the thalamus and lateral geniculate body. 

 Destructive lesion of the occipito-thalamic radiation of either side 

 produces hemianopia and atrophy of the same side of both retinae. 



(6) Acustic Radiation or Radiatio Temporo-thalamica (Fig. 

 70). Another pencil of fibers radiates from the region of the 

 medial geniculate body through the internal capsule to the audi- 

 tory area in the temporal lobe. It constitutes the temporo- 

 thalamic radiation. Its fibers are also in part corticifugal in 

 direction. If the temporo-thalamic radiation be destroyed the 

 result is partial deafness affecting chiefly the opposite ear. 



According to von Bechterew certain lesions in the thalamus have 

 been accompanied by loss of facial movements expressing emotion. 



The red nucleus (nucleus ruber] of the tegmentum is situated 

 beneath the thalamus (Figs. 42 and 46). It is a relay-station 

 in the indirect sensory tract, receiving the opposite brachium 

 conjunct! vum cerebelli and, by its axones, continuing the tract 

 to the thalamus and somaesthetic cortex. It also receives efferent 

 axones from the cerebral cortex (Beevor and Horsley) 'and gives 

 origin to two bundles: (a) One centrifugal bundle of axones, 

 (the rubro-spinal tract), after crossing over in the ventral decussa- 

 tion of the tegmentum (Forel's) descends, first, with the medial 

 portion of the lateral fillet ; second, through the lateral area of the 

 medulla, and, third, through the lateral part of the spinal cord. 

 Gradually diminishing, it disappears at the first lumbar segment. 

 It ends in the lateral columna and center of the gray crescent of 

 the spinal cord, (b) The red nucleus also sends a bundle of 

 axones through the opposite brachium conjunctivum of the cere- 

 bellum to the nucleus dentatus. 



