(A) Without resting intervals mean intra-group weights decay (purple), followed by a decay in connectivity (bottom panel). Weights between control neurons (grey) and between different assemblies or assembly and control neurons (green) remain low. Dashed line depicts theoretical prediction; shading represents standard deviation. (B) Reactivation during rest phases rescues the assemblies. (C) Connectivity matrix depicting the sum of weights (top) and number of synapses (bottom) between 120 exemplary neurons at the end of the simulation in panel B. (D) Simulation with the same sequence of sensory and rest phases, but all structural plasticity is blocked after learning (). The memory is retained for a while, but after about 100 hr, when there is a longer period without reactivation, the assemblies decay. (E) Connectivity matrices as in panel C for the simulation in panel D. Although the number of synapses is similar, the synaptic weights have decayed.