| 1. |
- Lansner, Anders, et al.
(author)
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Reactivation in Working Memory : An Attractor Network Model of Free Recall
- 2013
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8, s. e73776-
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Journal article (peer-reviewed)abstract
- The dynamic nature of human working memory, the general-purpose system for processing continuous input, while keeping no longer externally available information active in the background, is well captured in immediate free recall of supraspan word-lists. Free recall tasks produce several benchmark memory phenomena, like the U-shaped serial position curve, reflecting enhanced memory for early and late list items. To account for empirical data, including primacy and recency as well as contiguity effects, we propose here a neurobiologically based neural network model that unifies short- and long-term forms of memory and challenges both the standard view of working memory as persistent activity and dual-store accounts of free recall. Rapidly expressed and volatile synaptic plasticity, modulated intrinsic excitability, and spike-frequency adaptation are suggested as key cellular mechanisms underlying working memory encoding, reactivation and recall. Recent findings on the synaptic and molecular mechanisms behind early LTP and on spiking activity during delayed-match-to-sample tasks support this view.
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| 2. |
- Sikström, Sverker, et al.
(author)
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Using the cue elimination technique to derive an equation between performance in episodic tests
- 2004
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In: European Journal of Cognitive Psychology. - : Informa UK Limited. - 1464-0635 .- 0954-1446. ; 16:4, s. 481-510
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Journal article (peer-reviewed)abstract
- Lawful equations describing relations between empirical measurable variables, that are free of fitted parameters, and that can be derived from simple assumptions, are rare in psychology. However, this paper proposes one such equation that describes the relation between the performances on four different explicit episodic memory tests: free recall, cued recall, recognition, and cued recognition. The performance on each test is determined by the strength of three different and independent cues: the event cue, the context cue, and the target cue. The Cue Elimination Technique (CET) is introduced where cues are eliminated so that equations can be rewritten so that performance on three tests can be used to predict performance on the fourth test. Results from five conditions show a nonsignificant deviation between the predicted and the empirical probabilities of retrieval. Two estimates of each cue strength, which are based on different data sets, can be made so that the cue strengths can be empirically validated. Manipulations of psychological variables produce meaningful effect on the cue strengths so that CET can be used to dissociate cue strengths in episodic memory.
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