title: Repeated stimulation of cultured networks of rat cortical neurons induces parallel memory traces.
abstract: During systems consolidation, memories are spontaneously replayed favoring information transfer from hippocampus to neocortex. However, at present no empirically supported mechanism to accomplish a transfer of memory from hippocampal to extra-hippocampal sites has been offered. We used cultured neuronal networks on multielectrode arrays and small-scale computational models to study the effect of memory replay on the formation of memory traces. We show that input-deprived networks develop an activity⇔connectivity balance where dominant activity patterns support current connectivity. Electrical stimulation at one electrode disturbs this balance and induces connectivity changes. Intrinsic forces in recurrent networks lead to a new equilibrium with activity patterns that include the stimulus response. The new connectivity is no longer disrupted by this stimulus, indicating that networks memorize it. A different stimulus again induces connectivity changes upon first application but not subsequently, demonstrating the formation of a second memory trace. Returning to the first stimulus does not affect connectivity, indicating parallel storage of both traces. A computer model robustly reproduced experimental results, suggesting that spike-timing-dependent plasticity and short time depression suffice to store parallel memory traces, even in networks without particular circuitry constraints.
authors.affiliation: Department of Biomedical Signals and Systems, University of Twente, MIRA Institute for Biomedical Engineering and Technical Medicine, Enschede 7500 AE, The Netherlands Department of Clinical Neurophysiology, University of Twente, Enschede 7500 AE, The Netherlands j.lefeber@utwente.nl.
authors.forename: Joost
authors.initials: J
authors.lastname: le Feber
authors.affiliation: Department of Biomedical Signals and Systems, University of Twente, MIRA Institute for Biomedical Engineering and Technical Medicine, Enschede 7500 AE, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Witteveen
authors.affiliation: Department of Biomedical Signals and Systems, University of Twente, MIRA Institute for Biomedical Engineering and Technical Medicine, Enschede 7500 AE, The Netherlands Department of Radiology, Maastricht University, School for Mental Health and Neuroscience, Maastricht University Medical Centre, Maastricht 6200 MD, The Netherlands.
authors.forename: Tamar M
authors.initials: TM
authors.lastname: van Veenendaal
authors.affiliation: Department of Biomedical Signals and Systems, University of Twente, MIRA Institute for Biomedical Engineering and Technical Medicine, Enschede 7500 AE, The Netherlands.
authors.forename: Jelle
authors.initials: J
authors.lastname: Dijkstra
mesh_terms: D000200:Action Potentials; D000818:Animals; D002478:Cells, Cultured; D003198:Computer Simulation; D004558:Electric Stimulation; D008568:Memory / Q000502:physiology*; D008839:Microelectrodes; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017208:Rats, Wistar