Multiple-object Working Memory--A Model for Behavioral Performance

Amit, Daniel J.; Bernacchia, Alberto; Yakovlev, Volodya

doi:10.1093/cercor/13.5.435

Cited by 56 publications

(55 citation statements)

References 23 publications

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“…In addition, retroactive interference in the RU condition is usually reported to be stronger than proactive interference in the UR condition (Cowan 2001). This is the case in the model mainly because at prime2 onset, the perceptual response of the population coding for the prime2 is larger-and generates stronger feedback inhibition-than the retrospective activity of the prime1, as it is the case during the processing of sequences of items (see Amit et al 2003). The different effects of proactive and retroactive interference on the level of activation of RU and UR associates are increased by the spike frequency adaptation of the rates of neurons populations, which makes possible the semantic priming shift between activation of RU associates to the prime1 and activation of UR associates to the prime2.…”

Section: Activation and Interferencesmentioning

confidence: 90%

“…In the model, the nonselective inhibitory feedback proportional to the global level of activation of the items, sets a limit to the working memory system in which interference occurs when maximum capacity is reached (Cowan 2001;Amit et al 2003; see Haarmann and Usher 2001 for a review). Therefore, the limit of the overall amount of activation implies a selection of which RU and/or UR associates are activated and which are not.…”

Section: Activation and Interferencesmentioning

confidence: 99%

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Dynamics of the semantic priming shift: behavioral experiments and cortical network model

et al. 2012

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Multiple semantic priming processes between several related and/or unrelated words are at work during the processing of sequences of words. Multiple priming generates rich dynamics of effects depending on the relationship between the target word and the first and/or second prime previously presented. The experimental literature suggests that during the on-line processing of the primes, the activation can shift from associates to the first prime to associates to the second prime. Though the semantic priming shift is central to the on-line and rapid updating of word meanings in the working memory, its precise dynamics are still poorly understood and it is still a challenge to model how it functions in the cerebral cortex. Four multiple priming experiments are proposed that crossmanipulate delays and association strength between the primes and the target. Results show for the first time that association strength determines complex dynamics of the semantic priming shift, ranging from an absence of a shift to a complete shift. A cortical network model of spike frequency adaptive neuron populations is proposed to account for the non-continuous evolution of the priming shift over time. It allows linking the dynamics of the priming shift assessed at the behavioral level to the nonlinear dynamics of the firing rates of neurons populations.

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Section: Activation and Interferencesmentioning

confidence: 90%

Section: Activation and Interferencesmentioning

confidence: 99%

Dynamics of the semantic priming shift: behavioral experiments and cortical network model

et al. 2012

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“…This in turn requires a model explaining why capacity is limited. Although our understanding of the mechanistic basis of vsWM storage in local cortical circuits has advanced greatly through the integration of monkey neurophysiology data and biophysically detailed computational models (2,(21)(22)(23)(24)(25)(26)(27)(28)(29), storage of multiple items has only recently been investigated with these techniques (21,22,(30)(31)(32). Neuronal factors that affect vsWM have been identified, but how they interact to determine capacity is unclear.…”

mentioning

confidence: 99%

Mechanism for top-down control of working memory capacity

Edin

Klingberg²,

Johansson³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

336

319

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Working memory capacity, the maximum number of items that we can transiently store in working memory, is a good predictor of our general cognitive abilities. Neural activity in both dorsolateral prefrontal cortex and posterior parietal cortex has been associated with memory retention during visuospatial working memory tasks. The parietal cortex is thought to store the memories. However, the role of the dorsolateral prefrontal cortex, a top-down control area, during pure information retention is debated, and the mechanisms regulating capacity are unknown. Here, we propose that a major role of the dorsolateral prefrontal cortex in working memory is to boost parietal memory capacity. Furthermore, we formulate the boosting mechanism computationally in a biophysical cortical microcircuit model and derive a simple, explicit mathematical formula relating memory capacity to prefrontal and parietal model parameters. For physiologically realistic parameter values, lateral inhibition in the parietal cortex limits mnemonic capacity to a maximum of 2-7 items. However, at high loads inhibition can be counteracted by excitatory prefrontal input, thus boosting parietal capacity. Predictions from the model were confirmed in an fMRI study. Our results show that although memories are stored in the parietal cortex, interindividual differences in memory capacity are partly determined by the strength of prefrontal top-down control. The model provides a mechanistic framework for understanding topdown control of working memory and specifies two different contributions of prefrontal and parietal cortex to working memory capacity.computer model ͉ fMRI ͉ lateral inhibition ͉ prefrontal ͉ short-term memory ͉ parietal

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“…As a consequence, when maximum capacity is reached, interference perturbs the processing of the items (Amit, Bernacchia, & Yakovlev, 2003;see Haarmann & Usher, 2001, for a review). The processing of items generates proactive interference that can perturb the processing of subsequent items and, to a larger extent, retroactive interference that can perturb the processing of preceding items.…”

Section: Behavioral Correlates Of Activation and Interferencementioning

confidence: 99%

“…In cortical network models, excitatory neurons coding for items also activate inhibitory interneurons that provide regulatory negative retro-action preventing runaway excitation of the entire network (e.g., Amit, Bernacchia, & Yakovlev, 2003;Amit & Brunel, 1997). Therefore, in multiple priming, processing of the sequential primes and their activated associates generates unselective inhibition proportional to the overall level of activation.…”

Section: Neural Correlates Of Activation and Interferencementioning

confidence: 99%

Early dynamics of the semantic priming shift

Lavigne¹,

Chanquoy²,

Dumercy³

et al. 2013

ACP

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semantic processing of sequences of words requires the cognitive system to keep several word meanings simultaneously activated in working memory with limited capacity. the realtime updating of the sequence of word meanings relies on dynamic changes in the associates to the words that are activated. Protocols involving two sequential primes report a semantic priming shift from larger priming of associates to the first prime to larger priming of associates to the second prime, in a range of long soAs (stimulus-onset asynchronies) between the second prime and the target. however, the possibility for an early semantic priming shift is still to be tested, and its dynamics as a function of association strength remain unknown. three multiple priming experiments are proposed that cross-manipulate association strength between each of two successive primes and a target, for different values of short soAs and prime durations. results show an early priming shift ranging from priming of associates to the first prime only to priming of strong associates to the first prime and all of the associates to the second prime. We investigated the neural basis of the early priming shift by using a network model of spike frequency adaptive cortical neurons (e.g., deco & rolls, 2005), able to code different association strengths between the primes and the target. the cortical network model provides a description of the early dynamics of the priming shift in terms of pro-active and retro-active interferences within populations of excitatory neurons regulated by fast and unselective inhibitory feedback.

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Multiple-object Working Memory--A Model for Behavioral Performance

Cited by 56 publications

References 23 publications

Dynamics of the semantic priming shift: behavioral experiments and cortical network model

Dynamics of the semantic priming shift: behavioral experiments and cortical network model

Mechanism for top-down control of working memory capacity

Early dynamics of the semantic priming shift

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