In vertebrate CNS neurons, synapses are on dendritic spines. Most of the postsynaptic receptors are on the spine head, which are attached to the dendrite through a very small spine neck. What is the consequence of this small neck? Select all that apply.
A) The creation of independent chemical and electrical compartments.
B) It creates the ability to modulate synaptic inputs independently.
C) It traps ions in specific locations in the neuron.
D) It creates the possibility that synaptic connections will be lost over time as they will break off.

Question

Quizplus · Accepted Answer

The small neck allows synaptic inputs to be treated and modulated somewhat independently. (c) is incorrect as ions are too small to be trapped, although there is a local build-up of particular ions, like Ca²⁺. Although synapses can grow and recede in active synaptic plasticity, they do not break off.

In Vertebrate CNS Neurons, Synapses Are on Dendritic Spines