Extended Data Fig 7. Working model comparing permanent versus transient forgetting.

Two forms of forgetting include permanent (red) and transient (orange) forgetting. Left, Permanent forgetting involves a PPL1 DAn that synapses onto the γ2α’1-MBn compartment (red). The slow, ongoing DAn activity after learning is transduced by the G_q-coupled, DAMB receptor. This forgetting signal mobilises the Scribble scaffolding complex and recruits Rac1, PAK3 and Cofilin to erode labile, nonconsolidated memory. The cellular memory traces formed and stored in the following neuron, γ2α’1-MBOn, are also eroded. This process can be exacerbated by enhanced sensory stimulation (+), or repressed by sleep/rest (−). Right, Transient forgetting incorporates a different PPL1 DAn that synapses onto the α2α’2-MBn compartment (orange). This forgetting signal, transduced by DAMB, temporarily impairs the expression of consolidated, PSD-LTM. The cellular memory traces stored in α2sc-MBOn are not abolished after activating the forgetting pathway. This process can be triggered by interfering or distracting stimuli (+) to transiently block the retrieval of PSD-LTM.