The neuron is an excitable cell. There are, at least,
two types of neurons ;
- the sensitive neuron, cell of information.
- the motoneuron, cell of connection between
the nervous centers and muscles.
One of the first methods to study
the neuron was electricity. The means, most employed, were the D.C. current and
its derived forms ; *Rectangular impulses*. These techniques made it possible
to highlight *electric* properties of neuron;
- The neuron is sensitive to electricity.
- The current of stimulation is subliminal when the
*electric* response of neuron remains local.
- The current of stimulation is liminal (and
supraliminal) when the *electric* response of the neuron is propagated.
- The propagation of response, along the axon, is
a slow phenomenon.
- The propagated response, is identical when the
intensities of stimulations remain liminal and supraliminal.
- It takes a certain intensity and a certain time
so that there is a propagated response.
- The neuron make a spike to a certain quantity of electric
charge brought.
- If the charge is brought, too quickly, there is no
spike.
- If the charge is brought, too slowly, there is no
spike.
- The impedance of neuron membrane
varies according to the frequency.
- The neuron response to electric
stimulation, is never immediate.
- The rheobase is the minimal liminal intensity
for an impulse of long duration.
Certain arbitrary properties, were
invented by man :
- Chronaxy is the duration of a rectangular impulse
(liminal) of double intensity to rheobase.
- The effective time is the minimal duration of a
rectangular impulse to obtain a propagated answer.
- The limiting slope is the minimal slope which
must have the boarding time of the impulse for entrainer a propagated response.
