PHYSIOLOGY. 



them. They are without doubt connected with sensory areas in 

 function. The six sense areas in the cortex, namely, those of smell, 

 touch, muscle-sense, sight, taste, and hearing, are proportional in 

 size to the nerve or nerves supplying them. For example, the tactile 

 and muscle sense area is greatest, while the visual area is larger than 

 the auditory. The structure of each area corresponds to the struc- 

 ture of the sense organ. Thus the visual area has many layers of 

 cells, thus corresponding to the many layers in the retina. The 

 olfactory area has ,the fewest layers, thus heing in agreement with 



Fig. 283. Lateral View of a Human Hemisphere, Showing the Bundles 

 of Association Fibers. (STARR. ) 



A, A, Between adjacent gyri. B, Between frontal and occipital areas. C, 

 Between frontal and temporal areas, cingulum. D, Between frontal and temporal 

 areas, fasciculus uncinatus. E, Between occipital and temporal areas, fasciculus 

 longitudinalis inferior. C, N, Caudate nucleus. O, T, Optic thalamus. 



the cells of the olfactory mucous membrane. The area for hearing 

 in the cortex is twice as thick there as in the rest of the temporal 

 convolution. Hence each area is to be considered as a repetition, in 

 the cortex, of a peripheral sense organ. Flechsig suggests the name 

 of projection fields for the seven primary sense areas. 



As to the great sense area for touch and muscle sense, it is found 

 that the sensory paths for the legs are the first to reach the cortex, 

 and end in the paracentral lobule at the upper third of the ascend- 

 ing parietal convolution, extending on to the posterior surface of 



