Practice question · Sort into groups
Sort each scenario by the kind of summation it illustrates.
Groups: Temporal summation · Spatial summation
- EPSPs from fifty different synapses arrive at the same instant
- Excitation from many locations minus inhibition from others is tallied at once
- One synapse fires three times in rapid succession, its EPSPs piling up
- A single input fires again before its first EPSP has decayed
Hints
- 'Temporal' is about timing at ONE synapse; 'spatial' is about MANY synapses across space.
- If the key detail is 'in quick succession', think time; if it is 'many places at once', think space.
Show the answer
Temporal summation: One synapse fires three times in rapid succession, its EPSPs piling up, A single input fires again before its first EPSP has decayed
Spatial summation: EPSPs from fifty different synapses arrive at the same instant, Excitation from many locations minus inhibition from others is tallied at once
Why
Temporal summation stacks repeated EPSPs from one synapse over time; spatial summation adds inputs from many synapses arriving together (and subtracts IPSPs). The distinction is whether the inputs are separated in time or in location.
Practise Synaptic Transmission
The app has 5 more questions on this lesson, and keeps your place in the course. Psychology I is free to start.
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