What effect do excitatory potentials have on a neuron?

Excitatory potentials, specifically known as excitatory postsynaptic potentials (EPSPs), have a crucial role in the activity of neurons. When a neurotransmitter binds to the receptors on the postsynaptic neuron, it typically causes an influx of positive ions, such as sodium, into the neuron. This influx leads to a depolarization of the neuron’s membrane potential, moving it closer to the threshold required for triggering an action potential.

When the membrane potential becomes more positive, the neuron becomes more likely to reach this action threshold. If enough excitatory inputs occur or if they are strong enough, the neuron may reach the threshold and subsequently fire an action potential. Thus, excitatory potentials increase the probability of the neuron firing, which is why the correct answer highlights that they make it more likely to fire. This is a fundamental concept in understanding how neurons communicate and process information in the nervous system.