ELECTROPHYSIOLOGICAL STUDIES ON HUMAN 

 TASTE NERVES 



H. DiAMANT, M. FUNAKOSHI*, L. StROM aild Y. ZOTTERMAN 



Ear Clinic of Karolinska Sjukhuset, Stockholm and the Department of 

 Physiology, Veterinarhogskolan, Stockholm 51 



The first attempts to record the electrical gustatory response of man were 

 made in order to solve the problem whether man, like the monkey and 

 many other species, has gustatory fibres responding positively to water. 

 By a freak of nature the gustatory fibres from the anterior tongue separate 

 from the lingual nerve trunk and run through a bone channel into the 

 middle ear, where it is often exposed during otological operations. The 

 first experiments to place leads on the chorda tympani during middle ear 

 operations were made during the years 1956-57 in Sodersjukhuset, Stock- 

 holm by Ahlander and one of us (Y.Z.). Out of ten trials in which the 

 surgeon applied the electrodes to the exposed chorda tympani in the cavum 

 tympani, we obtained very weak signals in only two cases in response to 

 cold and gustatory stimulation of the tongue. However, the responses were 

 just audible in the loudspeaker and could not be recorded. 



In 1958 successful experiments were performed in the Ear Clinic of 

 Karolinska Sjukhuset, Stockholm, during operations undertaken in an 

 effort to mobilize the stapes (Diamant and Zotterman, 1959). In these 

 experiments we recorded the integrated electrical response of the nerve 

 to touch and to various taste solutions. As will be seen from Fig. 1 

 there was a good response to 0.5 m NaCl solution, 15 per cent sucrose, 

 0.04 per cent saccharine, 0.02 vi quinine sulphate and 0.2 m acetic acid. 

 However, the application of water to the tongue was followed by a reduc- 

 tion in the spontaneous activity in the nerve in exactly the same fashion as 

 we had previously found in the rat, which does not possess any taste 

 fibres that respond positively to water. 



This report presents the results of further experiments on man giving 

 more detailed information about nerve responses to various sapid sub- 

 stances. 



TECHNIQUE AND PROCEDURE 



Experiments were carried out on 32 otosclerotic cases undergoing a 



* On leave from the Department of Physiology, Dental School, Osaka University, 

 Osaka, Japan. 



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