The Virtual Nerve

3) stimulus strength form 1 to 10 mA

The minimal current/threshold current is 6nA. When below threshold current, slightly increased of mV when stimulate nerve in 1 to 5 nA. However, when increase the stimulus strength above threshold, no change in the amplitude(shows from the graph in peaks 6 to 10).

4) When the stimulus is set to repeated in 100 Hz and 8nA, it has a constant action potential amplitude.

100Hz

When further increase the frequency to 200Hz, which mean every 2nd stimulation generate an action potential, small peak appeared between two big peaks(little peaks are 62mV and big peaks are 43Mv).

200Hz

When 400Hz, every third stimulation generate a action potential, two small peak appear between two big peaks(small peak is 33mV in average and big peaks have 43Hz).

400Hz

When 600Hz, about four little peaks appear between two big peaks.

600Hz

So when the frequency increase, the numbers of little peaks increase because the stimulation is sent to the neuron, but it can’t response that quickly, so it appears those little peaks which show the incomplete response, which mean it haven’t response the stimulation when the frequency is too high.

Resting membrane potential stays the same as membrane is not permeable to sodium at rest.

Extracellular sodium concentration from 120mM to 1mM

Resting membrane potential is -79mV

When stimulation with difference sodium concentration in 200, 160, 120, 80, 40, 20 and 1mM, the peaks is 54, 50, 48, 35, 20 ,5 and -44mV respectively.

120 to 200mM

Extracellular potassium concentration from 1 to 35 mM

when the extracellular potassium concentration change in 1, 5, 15,25, 35mM, the

resting potential change to -102, -78, -50, -32, -27. The firing of action potential decrease when the concentration of potassium increase outside the cells because usually the gradient between extra and intercellular is large (intercellular have more k+ ions), but when the extracellular now have more K+ ions, it...