2A putative nanoscale molecular ensemble within the bounds of a glutamatergic synapse in the brain. The concept stems from the observation using super-resolution imaging that proteins involved in neurotransmitter release in the presynaptic active zone cluster in close trans-cellular alignment with clusters of neurotransmitter receptors in the postsynaptic density. The use of the word "column" thus refers to the extended structure of this protein accumulation, which stretches axially across the synapse from one cell to the next, and also alludes to the important historical concept of the "cortical column" in neuroscience, which summarizes the finding that functionally related