How does a neuron decide whether or not to produce action potentials?

Answer 1

A neuron decides whether or not to produce an action potential by a summation of excitatory and inhibitory signals at the trigger point of the neuron, the axon hillock (or, the initial segment of the axon immediately following the axon hillock), plus a sufficient density of voltage-gated sodium ion pores at the trigger point.

Neurons can receive both excitatory and inhibitory inputs at the same time, and if a confluence of those multiple signals at the axon hillock/initial axon segment (or alternatively, an occasion of sufficiently quickly repeated excitatory signals) sums to yield a membrane potential there of about -55 mv, this will cause the large number of voltage-gated sodium ion pores present there to open, allowing a sufficient influx of sodium ions to raise the membrane potential momentarily higher, which depolarizes adjacent regions of the axon, allowing more voltage-gated ion pores to open, allowing more sodium ions in; these actions repeat and continue along the axon, achieving the action potential.

It's important to understand that although the level of the summation of signal voltages is the trigger for the action potential, the initial firing of the action potential could not occur if there wasn't a sufficient density of voltage-gated sodium ion pores at the trigger point to allow sufficient sodium ions in to cause the membrane potential in adjacent regions to be high enough to open theirv-gated Na ion pores, so that the action potential could continue to propagate along the axon.

Answer 2

A neuron decides to produce action potentials based on the balance of excitatory and inhibitory signals it receives. If the sum of excitatory signals surpasses a certain threshold, the neuron will fire an action potential. In contrast, if inhibitory signals prevail, the neuron is less likely to produce action potentials.