What happens to a neuron's membrane between −70 mV and +30 mV? · Grey Matter

Inputs nudge the resting voltage of about −70 mV upward until it reaches threshold, near −55 mV, where voltage-gated sodium channels open together.

What happens to a neuron's membrane between −70 mV and +30 mV?

Inputs nudge the resting voltage of about −70 mV upward until it reaches threshold, near −55 mV, where voltage-gated sodium channels open together. Sodium floods in and the inside swings positive to about +30 mV in a fraction of a millisecond. The sodium channels then inactivate and potassium channels open, so potassium leaves and the voltage drops back, briefly below rest. The whole cycle takes one to two milliseconds, and the spike is always the same size: a stronger input changes how often the neuron fires, never how high.