What characterizes an excitatory neurotransmitter?

An excitatory neurotransmitter is characterized by its ability to increase the likelihood of a neuron firing an action potential. When an excitatory neurotransmitter binds to receptors on the postsynaptic neuron, it typically results in depolarization, making the inside of the neuron more positively charged. This change in membrane potential brings the neuron closer to the threshold needed to initiate an action potential, which is the signal that travels down the neuron.

For example, neurotransmitters such as glutamate are widely recognized as excitatory, as they play a crucial role in synaptic plasticity and learning by enhancing the communication between neurons. In essence, excitatory neurotransmitters promote the transmission of signals by encouraging the firing of neurons, thus playing a vital role in numerous psychological and physiological processes.