Amplitude control in synaptic transmission ensures that postsynaptic responses scale with what?

Amplitude control in synaptic transmission ensures that postsynaptic responses scale with what?

• A. Neurotransmitter reuptake is faster with higher activity.
• B. Action potential amplitude increases with distance.
• C. The neuron fires at a fixed rate regardless of presynaptic input.
• D. It ensures that postsynaptic responses scale with presynaptic activity.

Answer: (D)

Amplitude control in synaptic transmission is about making the strength of the postsynaptic response track how actively the presynaptic neuron is firing. The size of a postsynaptic potential depends on how much neurotransmitter is released into the synaptic cleft, which rises with presynaptic activity and can be shaped by short-term plasticity mechanisms that adjust release probability and vesicle availability. This means stronger presynaptic input leads to larger, more reliable postsynaptic responses, within the dynamic range of the synapse. The other ideas don’t capture this relationship: reuptake affects how long transmitter stays in the cleft (temporal precision), action potential amplitude with distance isn’t about synaptic response scaling, and a fixed firing rate ignores presynaptic input. So the concept that best fits is that postsynaptic responses scale with presynaptic activity.

Amplitude control in synaptic transmission is about making the strength of the postsynaptic response track how actively the presynaptic neuron is firing. The size of a postsynaptic potential depends on how much neurotransmitter is released into the synaptic cleft, which rises with presynaptic activity and can be shaped by short-term plasticity mechanisms that adjust release probability and vesicle availability. This means stronger presynaptic input leads to larger, more reliable postsynaptic responses, within the dynamic range of the synapse. The other ideas don’t capture this relationship: reuptake affects how long transmitter stays in the cleft (temporal precision), action potential amplitude with distance isn’t about synaptic response scaling, and a fixed firing rate ignores presynaptic input. So the concept that best fits is that postsynaptic responses scale with presynaptic activity.