What does spatial summation specifically refer to?

What does spatial summation specifically refer to?

• A. Addition from a single synapse
• B. Temporal summation at one site
• C. Inhibition from multiple inputs
• D. Addition of simultaneous inputs from multiple synapses at different locations

Answer: (D)

Spatial summation is about how a neuron integrates signals arriving at different locations on its dendritic tree at roughly the same time. When several presynaptic neurons fire together, each produces a postsynaptic potential at its own synapse. These potentials propagate toward the soma and add up as they meet at the axon hillock. If the combined depolarization reaches the threshold, an action potential is triggered. This is different from temporal summation, where the same synapse fires repeatedly in quick succession to produce a buildup over time, and from a single-synapse response, which doesn’t involve summing inputs from different sites.

Spatial summation is about how a neuron integrates signals arriving at different locations on its dendritic tree at roughly the same time. When several presynaptic neurons fire together, each produces a postsynaptic potential at its own synapse. These potentials propagate toward the soma and add up as they meet at the axon hillock. If the combined depolarization reaches the threshold, an action potential is triggered. This is different from temporal summation, where the same synapse fires repeatedly in quick succession to produce a buildup over time, and from a single-synapse response, which doesn’t involve summing inputs from different sites.