THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



49 



FIG. 35. Victor Horsley and one of his experiments on the locaUzation of the motor cortex. (The 

 latter illustration from Trans. Congr. Am. Physic. Surg, i : 340, 1888.) 



systematic exploration had to wait for Gushing, 

 Foerster and Penfield in the modern age of neuro- 

 surgery, and for the development of clinical neuro- 

 physiological investigation. 



In the light of clinical oljser\ation and the results of 

 electrical stimulation, the concept that the cortical 

 grey matter acted as a whole and that motor function 

 had no representation above the basal ganglia began 

 to crumble. At this same period, the birth of a new 

 technique brought yet another method of approach 

 for the investigator. This was the recording of brain 

 potentials evoked by sen.sorv stimulation and the 

 discovery of the Ijrain's own electrical activity, the 

 dawn of electroencephalography. 



In 1875 Richard Caton (288), at the Royal Infir- 

 mary School of Medicine in Liverpool, while searching 

 for the cerebral counterpart of du Bois-Reymond's 

 action potential in nerve, not only found it, but 

 noticed that when both of his electrodes lay on the 

 cortical surface there was a continuous waxing and 

 waning of potential. This oscillation of the base line 

 was present in the unstimulated animal and Caton 

 proved it to be unrelated to respiratory or cardiac 

 rhythms. He also proved these fluctuations to be 

 biological in origin ijy showing them to be vulnerable 



288. Caton, Rich.^rd (1842-1926). The electric currents of 

 the brain. Brit. M. J. 2: 278, 1875. 



to anoxia and to anesthesia and to be abolished by 

 death of the animal. In his first work Caton's experi- 

 mental animal was the rabbit and his detecting 

 instrument was a Thomson's galvanometer. This 

 was in the days before photographic recording of 

 laboratory observations and Caton's first publication 

 of his findings took the form of a demonstration before 

 the British Medical Association (289). Superimposed 

 on these o.scillations Caton found potential swings 

 related to sensory stimulation and realized immedi- 

 ately the meaning of this for cerebral localization 

 studies. Caton went on to use monkeys and gave fur- 

 ther reports of his results in 1877 and in 1887 (290). 

 the latter at the International Medical Congress held 

 that year in Washington, D. C. 



Strangely enough, in spite of the prominent groups 

 before whom Caton gas'e his demonstrations and the 

 popular medical journal in which he reported them, 

 his work received little attention at the time, even 

 among English-speaking physiologists. Meanwhile in 

 Poland, a young a.ssistant in the physiology depart- 

 ment of the University of Jagiellonski in Krakow, 



289. Caton, R. Interim report on investigation of the electric 

 currents of the brain. Brit. M.J. i : Suppl. 62, 1877. 



290. Caton, R. Researches on electrical phenomena of cere- 

 bral grey matter. Tr. Ninth Internat. Med. Congr. 3 : 246, 

 1B87. 



