Theory 08/Micro to Milli/Synaptic plasticity
Plasticity Depends on Calcium Timing
The claim
Whether a synapse strengthens or weakens is set by the ratio of calcium decay time to the interval between spikes, not by the number of spikes.
01Mechanism
Calcium accumulates and decays; the integral over the interval determines which signalling pathway dominates, and the ratio sets the integral.
02Prediction
Direction should track the ratio.
03Refutation
Direction tracking spike count would remove the timing.