Artificial calcium transients demonstrate how learning rate, Ωw, and synaptic weight depend on calcium temporal dynamics. (a–d) To illustrate the relationship between calcium (a), τw (b), Ωw (c), and synaptic weight (d), we constructed three artificial calcium profiles with Heaviside functions. The calcium profiles are (1) 1,000 ions for 5 ms (red line), (2) 300 ions for 5 ms (yellow dashed line), and (3) 1,000 ions for 10 ms (blue dotted line).