[Spike discharges from skin receptors during cooling]

Using a crosscorrelation method some quantitative characteristics of afferent impulse discharges in the n. saphenus of cat were obtained during skin cooling. A 10 degrees C drop in the skin temperature at different cooling gradients caused activity in the A beta-, A sigma- and C-fibres. The C-fibres were activated first, than A delta-, A beta- and the quick-conductive A beta-groups successively. The latent period of the escitation of the C-fibres remained constant at different cooling rates of the skin, while for the A-fibres it increased with slowing down of the temperature drop rate. Both in A- and C-fibres the level of the maximum activity did not depend on the gradient of the skin cooling. But in all the mentioned groups of the fibres the starting time of the maximum activity decreased with the rise in the cooling rate.