392 ALBERT S. MORACZEWSKI 



sensory activities have been known for some time. But the cor- 

 responding secondary areas are a more recent discovery. Much 

 of our earlier knowledge regarding localization of brain function 

 was derived from accidental injuries to the human brain. 

 Thus, for example, cerebral vascular accidents (" strokes ") may 

 lead to paralysis of limb or speech. Recent experimentation 

 with animals has sought to determine functional centers in 

 the brain by electrodes. These are permanently implanted in 

 specific areas of the brain, mild electrical stimulation is applied, 

 and the behavior pattern of the animal is observed.^ An alterna- 

 tive procedure is to allow the animal to determine whether or 

 not it is to be so electrically stimulated.® From such experi- 

 ments it has been concluded that certain areas are " rewarding 

 centers " since the animal would repeatedly stimulate itself in a 

 seeming orgy of " pleasure " until it became physically ex- 

 hausted several hours later. Similarly in the same general areas 

 but at different specific points there have been discovered 

 centers which mediated punishing effects since the animal would 

 refrain from restimulation.^° Other studies involving experi- 

 mental destruction of specific nuclei of the hypothalamus 

 revealed centers which were apparently concerned with hunger, 

 anger and the sex drive.^^ These and other data have now 

 established the existence of functional centers in the brain for 

 drives and emotions as well as for motor and sensory activities. 

 Electrical stimulation of exposed temporal lobes of conscious 

 human subjects during neurological procedures has contributed 



* W. R. Hess, Diencephalon: Autonomic and Extrapyramidal Functions (New 

 York: Grune & Stratton, 1954). This work is a comprehensive EngHsh resume of 

 his original contributions which were reported in detail in Das Zwischenhim (Basel: 

 Schwabe, 1949) and in Die junktionelle organization des vegetativen N ervemysteme 

 (Basel: Schwabe, 1948). 



* J. Olds and P. Milner, " Positive Reinforcement Produced by Electrical Stimu- 

 lation of Septal Area and Other Regions of the Rat Brain," Journal of Comparative 

 and Physiological Psychology, XLVII (1954), 419; J. Olds, " Self-Stimulation of the 

 Brain," Science, CXXVII (1958), 315-324. 



^^ J. Olds, op. cit., pp. 317-324. 



^^ W. R. Hess, Hypothalamus und Thalamus (Stuttgart: Thieme, 1956) ; W. R. 

 Ingram, "The Hypothalamus," Clinical Symposia, VHI (1956), 117-56. 



