What determines whether a neuron will have an action potential triggered?

Whether a neuron will have an action potential triggered is determined by the algebraic summation of individual postsynaptic potentials (PSPs). When the net EPSP (excitatory postsynaptic potential) exceeds the threshold, the neuron will generate an action potential.

Action potentials are all-or-nothing events, meaning they either occur (above threshold) or they do not (below threshold). The threshold is a specific membrane potential that must be reached in order for an action potential to be triggered.

Each neuron has a different threshold, which is determined by a number of factors, including the type of neuron, the number of synapses it receives, and the strength of those synapses.

When a neuron receives an EPSP, the membrane potential becomes more positive. If the EPSP is strong enough, it will bring the membrane potential up to the threshold, causing an action potential to be triggered.

Conversely, when a neuron receives an inhibitory postsynaptic potential (IPSP), the membrane potential becomes more negative. This makes it less likely that the neuron will reach the threshold and generate an action potential.

The overall effect of all of the PSPs that a neuron receives is determined by the net EPSP. If the net EPSP is positive, the neuron is more likely to fire an action potential. If the net EPSP is negative, the neuron is less likely to fire an action potential.

The process of integrating PSPs and determining whether or not to fire an action potential is called "integration."