Variation of the input resistance and membrane potential of a neuron in trace formation.

Trace changes in electrical activity, input resistance (Rinp), and membrane potential (MP) of brain neurons are studied in the mollusk Limnaea stagnalis for intracellular stimulation with a sinusoidal threshold current with a frequency of 0.1 Hz during 20 min. Some neurons are shown to exhibit an effect of facilitation, a rise in the level of activity being attending by an increase in Rinp and depolarization.

[Changes in the input resistance and membrane potential of a neuron developing a trace effect].

Trace effects in the change of spike activity, input resistance (Rinp) and membrane potential of neurons of the mollusk brain were studied in 36 "silent" brain neurons of Limnaea stagnalis in conditions of 20-min intracellular application of sinusoidal current with the threshold frequency 0.1 Hz. Some neurons revealed the effect of facilitation: the rise of activity with membrane depolarization and an increase of Rinp.

[Specificity of the selective sensitivity of electrosensitive neuron membranes to low-frequency sinusoidal stimulation].

A difference in sensitivity of mollusk's neuron to intracellular injection of sinusoidal current (1-10 Hz; 5.10(-10)--5.10(-9) A) was found as well as the complete cessation of activity at certain frequency--amplitude characteristics of the current ("windows" of blocked activity) and an increasing activity at other frequency--amplitude parameters of the current ("windows" of growing activity).

[Quasielectrostatic manipulation of a single neuron: trace phenomena and comparison with intracellular excitation].

The investigation of quasielectrostatic impact (QESI) on the electrical activity of an isolated neuron of the mollusc brain was continued under conditions of continuous (20 min to 2 hours) and repeated applications. It was shown that the repeated application of QESI changes the level of electrical activity of the neurons. For different cells the repeated application of QESI produces an increase as well as a decrease of the neurons activity, while the thresholds of the frequency modulation of the spontaneously active and the excitation of the "silent" cells become lower.