ORIGINAL RESEARCH ARTICLE published: 28 February 2013 doi: 10.3389/fpsyg.2013.00076 A mathematical model of forgetting and amnesia Jaap M. J. Murre*, Antonio G. Chessa and Martijn Meeter Department of Psychology, University of Amsterdam, Amsterdam, Netherlands Edited by: We describe a mathematical model of learning and memory and apply it to the dynamics Oliver Hardt, McGill University, of forgetting and amnesia. The model is based on the hypothesis that the neural systems Canada involved in memory at different time scales share two fundamental properties: (1) repre- Reviewed by: Florentin Wörgötter, University sentations in a store decline in strength (2) while trying to induce new representations in Goettingen, Germany higher-level more permanent stores. This paper addresses several types of experimental Marco Steinhauser, Catholic and clinical phenomena: (i) the temporal gradient of retrograde amnesia (Ribot’s Law), (ii) University of Eichstätt-Ingolstadt, forgetting curves with and without anterograde amnesia, and (iii) learning and forgetting Germany curves with impaired cortical plasticity. Results are in the form of closed-form expres- *Correspondence: Jaap M. J. Murre, Department of sions that are applied to studies with mice, rats, and monkeys. In order to analyze human Psychology, University of Amsterdam, data in a quantitative manner, we also derive a relative measure of retrograde amnesia Weesperplein 4, Amsterdam 1018 XA, that removes the effects of non-equal item difficulty for different time periods commonly Netherlands. found with clinical retrograde amnesia tests. Using these analytical tools, we review stud- e-mail:
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