Excitability of single firing human motoneurones to single and repetitive stimulation (experiment and model).

The activity of single motoneurones of m. flexor carpi ulnaris (FCU) was investigated by recording their motor unit (MU) action potentials during weak and moderate voluntary muscle contractions. The MU firing rate range was 4.

[Reciprocal inhibition of human motor neurons at different firing rates].

Reciprocal inhibition (RI) has been studied for its effect on repetitive firing of single motoneurons in the extensor carpi ulnaris and soleus muscles of healthy subjects. The peristimulus time histograms (PSTHs) were plotted for different mean firing frequency of motoneurons. Changes in the interspike interval duration were analyzed.

[The action of a short inhibitory volley on human firing motoneurons (an experiment and a model)].

The influence of a short inhibitory volley on firing motoneurons of soleus and ext. carpi uln. was studied in human experiments and the results obtained were used as a basis for simulation.

Testing excitability of human motoneurones capable of firing double discharges.

Single motor unit (MU) action potentials were recorded from the flexor carpi ulnaris during its weak voluntary contraction in 6 healthy subjects. At low frequencies of motoneuronal firing (the average interspike interval ranged from 70 +/- 8 to 200 +/- 22 msec), double discharges with interspike intervals from 5 to 20 msec were seen from about one-fourth of all MUs (62 out of 249). Monosynaptic testing of the excitability of firing motoneurones was carried out to study the probable mechanism of doublets.

[Correlation of the discharge frequency of a firing motor neuron and the efficiency of an excitatory volley of Ia-afferents in man].

Single motor unit potentials of the flexor carpi ulnaris muscle were recorded during voluntary contraction and H-reflex was evoked. The afferent volley effectiveness was estimated by the firing index of a motoneuron. The background firing rate of motor units ranged from 3.