[Campbell Biology P.1127] How do excitatory postsynaptic potentials EPSPs and inhibitory post... | Practice Question

How do excitatory postsynaptic potentials EPSPs and inhibitory postsynaptic potentials IPSPs primarily differ in their effect on the postsynaptic membrane potential and the ion movements involved?

  • A: EPSPs cause depolarization by opening channels permeable to Na+, while IPSPs cause hyperpolarization or prevent depolarization by opening channels permeable to K+ or Cl-.
  • B: EPSPs cause hyperpolarization by opening channels permeable to K+, while IPSPs cause depolarization by opening channels permeable to Na+.
  • C: Both EPSPs and IPSPs cause depolarization, but EPSPs are stronger.
  • D: Both EPSPs and IPSPs cause hyperpolarization, but IPSPs are stronger.

Explanation

The text explains that an 'excitatory postsynaptic potential EPSP ' causes depolarization, bringing the membrane potential toward threshold, typically due to ion channels permeable to Na+ and K+. An 'inhibitory postsynaptic potential IPSP ' causes hyperpolarization, moving the membrane potential farther from threshold, often due to channels selectively permeable for only K+ or Cl-.