Stochastic receptor, channel, and calcium dynamics inform deterministic synaptic weight update. (a) A realistic thin spine with a volume of 0.045 µm3 serves as an example spine to consider how stochastic receptor and channel dynamics translate into calcium transients that inform synaptic weight update. Scale bar, 0.5 μm. (b) The model stimulus includes a set voltage profile that activates both NMDARs and VSCCs. We considered a single seed run (seed 1 for the realistic thin spine 39). (c) Activated, open NMDARs over time for a single simulation in the realistic geometry shown in a. (d) Activated, open VSCCs over time for a single simulation in the realistic geometry shown in a. (e) Calcium transient due to the channel and receptor dynamics shown in c and d. (f–h) Learning rate τw (f), Ωw (g), and synaptic weight update (h) calculated from the calcium transient in e.
