THERMORECEPTOR PHYSIOLOGY 
DISCUSSION 
DR. FREEMAN: I am enormously impressed with your re- 
cording from the C fibers. This is a remarkable accomplishment. 
I notice that the wave form was initially upwards, then downwards 
again. What is its polarity? 
DR. HENSEL: I do not know exactly how it was in this experi- 
ment. It is not always the case that you have waves in both direc- 
tions. 
DR. FREEMAN: Your technique for measuring time intervals 
will show your latency was at least as long as known latency. Is 
that correct? 
DR. HENSEL: We are measuring the time between the onset of 
the stimulus and the onset of the impulses at a certain distance 
from the stimulated point. 
DR. FREEMAN: Do you measure the degree of onset that 
accurately? 
DR. HENSEL: No, the conduction velocity has been measured 
by applying well defined rectangular electric shocks. The distance 
between stimulating and recording point of the nerve was about 
4 cm. 
DR. FREEMAN: How do you figure the onset of your cold 
stimulus? 
DR. HENSEL: This was measured by a thermocouple below the 
therm ode. 
DR. FREEMAN: But if your latency is amatter of milliseconds, 
what part of the onset of the cold do you take as your starting point 
for the stimulus threshold? 
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