714 



THE PSYCHO-SENSORIAL PATHS. 



fig. 4JS0), Ferrier locates the joint centres for smell and taste. These two centres 

 do not seem to be distinct locally from each other. 



4. Tactile Areas. According to Tripier and others, all the tactile cerebral 

 fields from different parts of the body coincide with the motor cortical centres for 

 these parts [compare p. 705]. 



Occasionally, in epileptics, strong stimulation of the sensory centres, as expressed in the 

 excessive subjective sensations, accompanies the spasmodic attacks (compare 393, 12). Such 

 epileptiform hallucinations, however, occur without spasms, aud are accompanied only by dis- 

 turbances of consciousness of very short duration (Bcrgcr). 



Course of the Sensory Paths. The nerve-fibres which conduct impulses from the 

 ssnsory organs to the sensory cortical centres pass through the posteriori' third of the 

 posterior limb of the internal capsule between the optic thalamus and the lenticular 

 nucleus (fig. 500, S). Hence, section of this part of the internal capsule causes 

 hemianaesthesia of the opposite half of the body (Charcot). In such a case, 

 sensory functions are abolished only the viscera retaining their sensibility. There 

 may also be loss of hearing, smell, and taste, and hemiopia (Bechterew). 



Pathological. In cases where there is more or less injury or degeneration of these paths, 

 there is a corresponding greater or less pronounced loss of the pressure and temperature sense, 

 of the cutaneous and muscular sensibility, of taste, smell, and hearing. The eye is rarely quite 

 blind, but the sharpness of vision is interfered with, the field of vision is narrowed, while the 

 colour sense may be partially or completely lost. The eye on the same side may suffer to a 

 slight extent. 



V. Numerous cases of injury of the anterior frontal region, without interference 

 with motor or sensory functions, have been collected by Charcot, Ferrier, and 



others. On the other hand, en- 

 feeblement of the intelligence 

 and idiocy are often observed in 

 acquired or congenital defects of 

 the prefrontal region. In highly 

 intellectual men, Kudinger found 

 in addition a considerable de- 

 velopment of the temporo-sphe- 

 noidal lobe. According to 

 Flechsig, there is no doubt that 

 the frontal lobes and the tem- 

 poro-occipital zone are related 

 to intellectual processes, more 

 especially the " higher" of these. 

 Topography of the Brain. The 

 relationsof the chief fissures and con- 

 volutions of the brain to the surface 

 of the skull are given in fig. 484, 

 the brain being represented after 

 Ecker. [Turner and others have 

 given minute directions for finding 

 the position of the different con- 

 volutions by reference to the sutures 

 and other prominent parts of the 

 skull. The annexed diagram by 

 R. "W. Reid shows the relation of 

 the convolutions to certain fixed 



Relation of the fissures and convolutions to the surface of IfaJfte wi^ 



the SCalD. +. most nrnniinnf >i-f n ( *1\ Q ^,.*l : llu _^ u g- * y 'M 



the fissure of 

 where its upper end joins 



the scalp. [The 



Rolando, 



nence ; a, convex line bounding parietal lobe below b 



a -j ii i- ^t. j- x , tained by measuring on the scalp K 



in the middle line the distance between the glabella and the external occipital protuberance, or 

 the inion which, in ordinary heads, varies from 11 to 13 inches (fig. 499). Measured from 

 before backwards, along this line, the distance from the glabella to the top of the fissure is 557 



