Final answer:
Glutamate is the neurotransmitter most often associated with excitatory postsynaptic potential (EPSP) due to its role in depolarizing the postsynaptic neuron and increasing the likelihood of triggering an action potential in the central nervous system.
Step-by-step explanation:
The neurotransmitter most often associated with the excitatory postsynaptic potential (EPSP) is glutamate. This is due to the fact that glutamate receptors on the postsynaptic membrane are directly responsible for the depolarization that characterizes an EPSP. In the central nervous system (CNS), glutamate functions as the primary excitatory neurotransmitter and is involved in a variety of neural communication processes, including learning and memory.
When glutamate binds to its receptors, it leads to the opening of ion channels that allow positive ions to flow into the neuron. This influx of positive ions causes depolarization of the postsynaptic neuron's membrane and increases the likelihood of triggering an action potential. The action of glutamate is contrasted with inhibitory neurotransmitters like GABA, which cause hyperpolarization and decrease the likelihood of an action potential being generated.
In summary, glutamate is the key neurotransmitter that mediates rapid excitatory signaling in the brain, playing a vital role in neural transmission and the resulting cognitive functions.