ABSTRACT
We propose a novel mechanism of synaptic maintenance whose goal is to preserve the performance of an associative memory network undergoing synaptic degradation, and to prevent the development of pathological attractors. This mechanism is demonstrated by simulations performed on a low-activity neural model which implements local neuronal homeostasis. We hypothesize that, whereas Hebbian synaptic modifications occur as a learning process during wakefulness and SWS consolidation, the neural-based regulatory mechanisms proposed here take place during REM sleep, where they are driven by bouts of random cortical activity. The role of REM sleep, in our model, is not to prune spurious attractor states, as previously proposed by Crick and Mitchison and by Hopfield Feinstein and Palmer, but to maintain synaptic integrity in face of ongoing synaptic turnover. Our model provides a possible reason for the segmentation of sleep into repetitive SWS and REM phases.
