Question

A single EPSP is not sufficient to bring about an action potential. You also notice an IPSP relatively equivalent in strength to the EPSP is happening at the same time. How might we get closer to an action potential?

a) If we trigger another EPSP quickly after the first
b) If the IPSP synapsed farther from the axon hillock
c) Amplification of EPSP by more neurotransmitter
d) Temporal summation of EPSP
e) All of the above

Answer 1

To get closer to an action potential, we may trigger another EPSP quickly, have IPSPs synapse farther from the axon hillock, amplify the EPSP by releasing more neurotransmitter, or utilize temporal summation of EPSPs. All these methods support reaching the threshold necessary for action potential generation, facilitating the communication between neurons.

Step-by-step explanation:

The student asked how we might get closer to an action potential when a single excitatory postsynaptic potential (EPSP) is not sufficient, and there's an inhibitory postsynaptic potential (IPSP) of equivalent strength occurring simultaneously. To increase the likelihood of an action potential occurring, several strategies can be utilized:

• If we trigger another EPSP quickly after the first, which is known as temporal summation.
• If the IPSP synapses farther from the axon hillock, reducing its influence on the action potential threshold.
• Amplification of EPSP by releasing more neurotransmitter into the synaptic cleft.
• Temporal summation of EPSPs can also help to reach the threshold needed to fire an action potential.

In summary, all the options listed (a through d) are viable methods to bring the neuron closer to reaching the threshold for an action potential. These options work because action potentials are an 'all-or-none' phenomenon; they either happen fully once the threshold is reached or do not happen at all. No single action potential is 'bigger' than another; instead, a stronger stimulus can cause action potentials to occur more frequently.