5. TEMPERATURE RECEPTORS
50
127
-
1
I
I
I
I
I
&
I
50
0
2
CT
6 2 0 0
-
1
I
I
I
I
I
0
u)
5 150
.- E
Fig. 2. Differences in the responses of cutaneous receptors of Leuciscus to
standard mechanical stimuli, tested at different temperatures. The fishes had
previously been adapted to 15OC for 4 weeks. The temperature of the skin was
changed by the gentle flow of water of the appropriate temperature, and mechanical
stimuli were applied with a small glass probe. All impulse frequencies are expressed
as a percentage of the response to the first stimulus at 6OC. The upper curve ( a )
sho\vs the responses to single stimuli (mean values from 10 experiments). The lower
curve ( b ) shows the adapted level to which the frequency falls with repeated stimuli
at l/sec (mean of 11 ) . Vertical lines indicate standard errors. From Spath ( 1967 ).
In fact, warm objects result in fewer impulses, and cold objects in more,
than do thermally neutral objects. The results are roughly quantitative
in that the greater the change of temperature the more rapid the change,
and thus the greater the effect on the response to mechanical stimuli.
Clearly, the question now arises as to whether such a system can
underlie the known temperature responses of fishes. There are two
problems, first, whether the CNS can disentangle the two modalities,
touch and temperature, and obtain useful information about both, and,
second, whether the recorded sensitivity can account for the known
thresholds (e.g., Table I ) .
A single bimodal, touch-temperature receptor can, in theory, give
information about temperature as long as there is independent evidence
50
127
-
1
I
I
I
I
I
&
I
50
0
2
CT
6 2 0 0
-
1
I
I
I
I
I
0
u)
5 150
.- E
Fig. 2. Differences in the responses of cutaneous receptors of Leuciscus to
standard mechanical stimuli, tested at different temperatures. The fishes had
previously been adapted to 15OC for 4 weeks. The temperature of the skin was
changed by the gentle flow of water of the appropriate temperature, and mechanical
stimuli were applied with a small glass probe. All impulse frequencies are expressed
as a percentage of the response to the first stimulus at 6OC. The upper curve ( a )
sho\vs the responses to single stimuli (mean values from 10 experiments). The lower
curve ( b ) shows the adapted level to which the frequency falls with repeated stimuli
at l/sec (mean of 11 ) . Vertical lines indicate standard errors. From Spath ( 1967 ).
In fact, warm objects result in fewer impulses, and cold objects in more,
than do thermally neutral objects. The results are roughly quantitative
in that the greater the change of temperature the more rapid the change,
and thus the greater the effect on the response to mechanical stimuli.
Clearly, the question now arises as to whether such a system can
underlie the known temperature responses of fishes. There are two
problems, first, whether the CNS can disentangle the two modalities,
touch and temperature, and obtain useful information about both, and,
second, whether the recorded sensitivity can account for the known
thresholds (e.g., Table I ) .
A single bimodal, touch-temperature receptor can, in theory, give
information about temperature as long as there is independent evidence