Why does a neuron fire more slowly after seconds of steady input? · Lobeworks/17

Slow processes pile up behind the fast refractory period.

Why does a neuron fire more slowly after seconds of steady input?

Slow processes pile up behind the fast refractory period. Calcium entering with each spike opens calcium-activated potassium channels, some sodium channels drop into a slow inactivated state that takes seconds to leave, and the sodium-potassium pump, pumping harder to restore the gradients, adds an outward current of its own with a time constant of up to a few seconds. Each pushes the next spike later, so under a constant input the rate falls over time, which is spike-frequency adaptation.