How could we test the relationship between long term potentiation and learning?
That's hard. Anyway. How could we test if increasing the surface area of a
terminal bouton results in increasing post-synaptic response? I guess first
it's necessary to affirm that it isn't a foregone conclusion that this
mechanism already operates. According to Dr P, the increase in the area of
a terminal bouton results in increase in the number of docking sites (mediated
by the presence of precursors for the creation of synaptotagimin and SNARE
molecules I suppose). We also know that under low-Ca++ concentrations, the
primary means of exocytosis into the synapse is through complete fusion and
collapse of the vesicles. However, the reason that under these conditions
(which are typical for at least some of the neurons) the result isn't to have
the boutons grow unbounded is that the membranes are also recycled into new
vesicles through the process of endocytosis
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2343565/ and others].
So anyway, first stop endocytosis at the axon terminal without hindering the
process of exocytosis or creation of new docking sites, or anything really
having to do with the movement of vesicles (if possible...maybe some virus?).
Second, monitor the extracellular concentration of neurotransmitter following
either the introduction of Ca++ into the terminal (this might be achieved also
with an AP, but that may have additional consequences not considered).