Weak stimulation sets a synaptic tag — a provisional mark that persists for roughly an hour. The tag alone is not enough for long-term potentiation. But if a stronger event occurs in the same neuron during that window, the plasticity-related proteins (PRPs) it synthesizes can be captured by any active tag, converting a transient change into a lasting one.
The memories shown below are mechanically identical. Which ones persist depends entirely on timing — specifically, whether the salient event falls within each memory's tag window. Drag the red marker to move the salient event and watch outcomes change.
The three memories are mechanically identical — same encoding strength, same salience. In a simple importance-based model, they should all survive or all fade equally. But their persistence depends on whether a separate, unrelated event falls within each one's tagging window.
In competition mode, the protein pool is limited. When more memories are tagged than proteins exist, the ones closest to the salient event win — not because they were more important, but because their tags were stronger at the moment of synthesis. Memory doesn't only compete with forgetting. It competes with adjacent memory for the same molecular resource.
One thing this simulation can't show: from inside the encoding event, there's no signal about which outcome follows. The synapse that gets consolidated and the one that fades are indistinguishable at the moment of formation. The gap between "something was encoded" and "something will be remembered" is invisible during the encoding itself.