GENERAL PHYSIOLOGY OF THE CEREBRUM. 



195 



toms accompanying the hemiplegia a disturbance of the swallowing 

 reflex or a diminution in the spinal reflexes. The nuclei in the 

 medulla and the cord suffer a diminution in irritability, although 

 not directly involved in the lesion. Monakow designates this re- 

 sult or condition under the term diaschisis,* which he defines as a 

 diminution in irritability within the whole connected functional 

 complex without anatomical lesion. It must also be borne in mind 

 in this connection that most of the efforts made hitherto to localize 

 the functional activities of the brain have had reference chiefly to 

 planes of separation vertical to the cortex. As indicated on p. 187, 



Fig. 86. To show the motor areas in the dog's brain as originally determined by Fritsch 

 and Hitzig: s, Sigmoid gyrus; A, center for the neck muscles; -H-, center for the extensors and 

 adductors of the forelimb; +, center for the flexors and rotation of forelimb; #, center for the 

 hind limb; Q Q center for the muscles innervated by the facial. 



recent investigations have indicated that it will be necessary to 

 consider also the separation of function along horizontal planes 

 (von Valkenburg). That is to say, it seems quite possible that the 

 several strata in the cortex, such as the granular, the infra- 

 granular, and the supragranular layers may mediate different ac- 

 tivities of the brain, or even different psychical functions. 



* von Monakow, "Ergebnisse der Physiologic," vol. xiii., 1913. 



