Excitatory postsynaptic potential (EPSP)

Definition

An excitatory postsynaptic potential (EPSP) is a temporary depolarization of the postsynaptic membrane caused by the flow of positively charged ions into the cell. This event increases the likelihood that the neuron will fire an action potential.

5 Must Know Facts For Your Next Test

1. EPSPs occur when neurotransmitters bind to receptors on the postsynaptic membrane, causing ion channels to open.
2. The main ions involved in generating EPSPs are sodium (Na+) and calcium (Ca2+).
3. Multiple EPSPs can summate temporally or spatially to reach threshold and trigger an action potential.
4. EPSPs are typically mediated by excitatory neurotransmitters such as glutamate and acetylcholine.
5. The strength and duration of an EPSP can be influenced by factors such as receptor type, neurotransmitter concentration, and synaptic plasticity.

Review Questions

• What ions are primarily responsible for generating an EPSP?
• How do multiple EPSPs contribute to neuronal firing?
• Which neurotransmitters are commonly associated with EPSPs?

Related terms

actionPotential: A rapid rise and fall in membrane potential that propagates along the axon of a neuron.

inhibitoryPostsynapticPotential(IPSP): A hyperpolarization of the postsynaptic membrane that decreases the likelihood of an action potential.

neurotransmitter: Chemical substances that transmit signals across a synapse from one neuron to another.