HENSEL, H. 
DR. KAWAMURA: Does each single cold or warm fiber have its 
own temperature range? 
DR. HENSEL: Yes, eachfiberhas its range of temperatures, but 
if you take the whole output of the nerve, then the maximum will be 
at a temperature of about 15 C. The whole output of the nerve is 
integrated as a whole spectrum of nerve fiber discharges. If you 
count the impulse traffic in a rather thick nerve preparation — 
it cannot be done very accurately — it will have a maximum at about 
15 C And this corresponds quite well to the subjective cold sen- 
sation under constant skin temperature. 
DR. STUART: What is the response to mechanical stimulus of 
the C fiber at the thirty-five impulse per second response? 
DR. HENSEL: Excuse me, this was no C fiber. This was an A 
fiber, a non-specific A fiber. 
DR. STUART: What was the discharge frequency during mechan- 
ical stimulation? 
DR. HENSEL: It was hi^er than 35. I think 120 or 130. With 
strong pressure you will get even higher frequencies, up to 300 
impulses /sec. I would like to emphasize that the temperature 
sensitivity of the non-specific fibers might be in the same range 
as that of the specific ones, but still the response to mechanical 
stimulation is much higher. 
DR. STUART: This migjit suggest the central nervous system 
decodes diverse modalities by these diverse frequencies, even along 
the same fiber. 
DR. HENSEL: Let us assume a non-specific fiber firing at 35 
impulses /sec. How can you discriminate between light pressure or 
strong cooling, both of which cause the same impulse frequency? I 
think the sensation mediated by this fiber is a specific mechanical 
sensation. There are also some experiences in daily life; for ex- 
ample, when a very cold wind is blowing into your face. You feel 
not only cold but you also have a strange sensation of pressure. 
This migjit be due to the discharge of such non-specific fibers. 
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