FORCED GRASPING AND GROPING IN RELATION TO THE SYNDROME OF THE PREMOTOR AREA

Abstract

Recent experimental studies¹ have indicated that forced grasping is an exaggerated postural reflex which may be induced in all animals of the primate series by lesions restricted to the premotor area of the cerebral cortex. The grasping phenomenon, however, is not an isolated reflex disturbance, since it is always associated with a number of equally striking signs and symptoms which taken together form, both in man and in animals, a well defined entity in neurology. This entity has been variously designated as "tonic innervation"² and as the "syndrome of the premotor area."³ As the physiologic basis of the syndrome is not yet clearly understood, the present experimental study was undertaken, in which special attention has been given to forced grasping and groping. METHODS Monkeys, baboons and chimpanzees were used as experimental subjects. Prior to operation many of the animals were trained to perform complex skilled movements, e.