Memory in cultured cortical networks: experiment and modeling

The mechanism behind memory is one of the mysteries in neuroscience. Here we unravel part of the mechanism by showing that cultured neuronal networks develop an activity connectivity balance. External inputs disturb this balance and induce connectivity changes. The new connectivity is no longer disrupted by reapplication of the input, indicating that a network memorizes the input. A different input again induces connectivity changes, but returning to the first input no longer affects connectivity, showing that memory traces are stored in parallel. Computer modeling supports these findings, and shows that spike timing dependent plasticity enables neuronal networks to store memory traces of different inputs in parallel.