Neurons

Opening Cl⁻ channels (allowing Cl⁻ influx) or K⁺ channels (allowing K⁺ efflux) leads to hyperpolarization, moving the membrane potential further away from the threshold and inhibiting the neuron.

Spatial summation is the additive effect of graded potentials occurring at different physical locations (synapses) on the neuron at the same time. Temporal summation occurs at a single synapse over time.

Acetylcholinesterase (AChE) is the enzyme located in the synaptic cleft that rapidly hydrolyzes ACh into acetate and choline, terminating the synaptic signal to prevent continuous stimulation.