John F. Fulton 209 



postures. Until very recently, few attempts had been made to discover whether 

 the responsiveness of the anterior lobe is discrete, that is, whether there is 

 separate representation of upper and lower extremities. All are agreed, how- 

 ever, that the homolateral side of the anterior lobe influences the homolateral 

 extremities to a greater extent than the contralateral. 



The recent studies of Gervase Connor^^ indicate that, both in dogs and in 

 monkeys, a maximal extensor release occurs when the anterior lobe is removed 

 as an isolated entity. The positive supporting reactions of Magnus become 

 grossly exaggerated, with head retraction and marked opisthotonos; in a pains- 

 taking analysis Connor finds that this extensor hyperactivity persists after de- 

 afferentation of the neck muscles, after bilateral labyrinthectomy and after 

 renroval of both cerebral hemispheres, but is destroyed by a posterior root 

 section which interrupts the proprioceptives to the extremity under exami- 

 nation. The exaggeration of positive supporting reaction is so intense, follow- 

 ing anterior lobe lesions, that it has given opportunity to study the question 

 of functional localization within the anterior lobe. Doctor Connor permits 

 me to mention the following new disclosures. 



A. Ciilmen.— When the culmen is removed as an isolated entity, leaving 

 centralis and lingula intact, positive supporting reactions are foiuid only in 

 the hindlimbs, the forelimbs being quote unaffected. If one lateral half of the 

 culmen is removed, positive supporting reactions are seen only in the hindlimb 

 on the same side. From this, Connor concludes that ftmctional representation 

 of the hindlimbs can be demonstrated in the culmen and in the culmen alone. 



B. Centralis.— Isolated removal of the posterior centralis causes positive sup- 

 porting reactions elicitable only in the forelimbs, and when the lateral half 

 of the centralis is removed the reactions are restricted to the forelimb on the 

 side of the lesion. From this Connor concltides that the posterior centralis pre- 

 sides over the antigravity reactions of the upper extremity. 



C. Li?igi{ la. —The lingula is peculiar in being the only portion of the ante- 

 rior lobe which receives vestibular in addition to spinocerebellar fibers. \V'hen 

 the entire anterior lobe is removed one of the striking symptoms, in addition 

 to positive supporting reactions of the extremities, is an extreme head retrac- 

 tion with obvious incoordination of the neck musculature. After isolated 

 lesions of culmen and centralis, this symptom does not occur and is only found 

 when the lingula is included in the ablation. Owing to its anatomical position, 

 it has been impossible as yet for Connor to remove the lingula as an isolated 

 entity, but from the evidence just presented it would seem an entirely logical 

 conclusion that the lingula presides over the neck musculature, and with its 

 vestibular connection stands as an integrator of the vestibtilar and the tonic 

 neck-reflex mechanisms. 



You will no doubt ask, how are these mechanisms related with the cerebral • 

 cortex? Their relation is less intimate than with the neocerebellum, btit in 

 Connor's analysis of the syndrome of the culmen, centralis, and lingula re- 

 spectively he finds that all reactions, such as the positive supporting reflex, are 



