EPSP and IPSP in Neurons: Understanding Excitation and Inhibition
What is the relationship between EPSP and depolarization, and IPSP and hyperpolarization?
a. hyperpolarization; depolarization
b. depolarization; hyperpolarization
c. spatial summation; temporal summation
d. temporal summation; spatial summation
Final answer: An EPSP, associated with depolarization, 'excites' a neuron, pushing it towards action potential threshold, while an IPSP, associated with hyperpolarization, 'inhibits' a neuron, pushing it away from threshold.
Answer:
An EPSP (Excitatory Postsynaptic Potential) is related to depolarization in the same way that an IPSP (Inhibitory Postsynaptic Potential) is related to hyperpolarization.
To elaborate, an EPSP is a slight depolarization of the postsynaptic cell's membrane potential caused by the flow of positively charged ions (like sodium) into the postsynaptic cell. This brings the membrane potential closer to the threshold for an action potential, thus 'exciting' the cell.
On the contrary, an IPSP is a slight hyperpolarization of the postsynaptic cell's membrane potential caused by the flow of negatively charged ions (like chloride) into the cell or positively charged ions (like potassium) out of the cell. This takes the membrane potential further from the threshold, 'inhibiting' the cell.
Understanding the balance between EPSP and IPSP is crucial in determining the overall excitatory or inhibitory effect on a neuron's firing rate and function.