Possible mechanisms for reducing memory confusion during sleep

Confusion readily occurs in memory processes between patterns that overlap substantially. Possible mechanisms are considered that might operate in an automatic manner to reduce such confusion. One such mechanism is the recall of patterns in a distorted way, so that they are enriched with greater activity in distinctive elements of experienced patterns than in overlapping elements. Selective consolidation based on such enriched patterns would reduce confusion in long-term recall and might benefit discrimination learning. It is shown how automatic algorithms could achieve this through a process with two phases. In the first phase, somewhat analogous to slow-wave sleep, it is necessary for the normal tendency of the nervous system to learn correlations of associated activity to be disabled. The second phase must occur while the cells most active in the first phase are relatively inexcitable. Enriched patterns would be generated during this phase through recall, which might be triggered by bursts of activity such as occur in rapid eye movement sleep. Selective consolidation would take place during the second phase. If such processes do occur in the nervous system, it seems likely that they would have evolved to occur during sleep.