| Abstract: | We investigated the impulse activity of 103 neurons in cats anesthetized with a mixture of chloralose and urethane. The following response characteristics were studied in detail: 1) the latent period of the first impulse as a function of tone intensity; 2) threshold as a function of duration; 3) the frequency-threshold curves under the action of short (1–2 msec) and long (100–200 msec) tones; 4) the discharge "pattern" and the number of impulses under the action of signals with different durations and intensities. We demonstrated that the temporal characteristics of different neurons exhibit substantial differences. The high positive correlation among the temporal characteristics investigated enabled us to distinguish three groups of neurons. The first group was characterized by the following properties: a) short latent periods with a threshold tone intensity; 2) a short summation time (or none at all); 3) similarity of the frequency-threshold curves for short and long signals; 4) an initial on-discharge of 1–3 impulses. The second group was characterized by: 1) long latent periods with a threshold tone intensity; 2) pronounced temporal summation; 3) steeper frequency-threshold curves when the tone duration was increased; 4) prolonged discharge.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 1, No. 2, pp. 137–146, September–October, 1969. |
