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Robust sequential working memory recall in heterogeneous cognitive networks.

Rabinovich MI, Sokolov Y, Kozma R - Front Syst Neurosci (2014)

Bottom Line: As a result, competitive network dynamics is qualitatively altered.The results are interpreted in the context of the winnerless competition principle.We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions.

View Article: PubMed Central - PubMed

Affiliation: BioCircuits Institute, University of California San Diego La Jolla, CA, USA.

ABSTRACT
Psychiatric disorders are often caused by partial heterogeneous disinhibition in cognitive networks, controlling sequential and spatial working memory (SWM). Such dynamic connectivity changes suggest that the normal relationship between the neuronal components within the network deteriorates. As a result, competitive network dynamics is qualitatively altered. This dynamics defines the robust recall of the sequential information from memory and, thus, the SWM capacity. To understand pathological and non-pathological bifurcations of the sequential memory dynamics, here we investigate the model of recurrent inhibitory-excitatory networks with heterogeneous inhibition. We consider the ensemble of units with all-to-all inhibitory connections, in which the connection strengths are monotonically distributed at some interval. Based on computer experiments and studying the Lyapunov exponents, we observed and analyzed the new phenomenon-clustered sequential dynamics. The results are interpreted in the context of the winnerless competition principle. Accordingly, clustered sequential dynamics is represented in the phase space of the model by two weakly interacting quasi-attractors. One of them is similar to the sequential heteroclinic chain-the regular image of SWM, while the other is a quasi-chaotic attractor. Coexistence of these quasi-attractors means that the recall of the normal information sequence is intermittently interrupted by episodes with chaotic dynamics. We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions.

No MeSH data available.


Related in: MedlinePlus

All-to-all inhibitory interactions between 6 modes (information items) of the cognitive network; excitatory self connections are not shown. Black arrows represent incoming signals.
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Figure 2: All-to-all inhibitory interactions between 6 modes (information items) of the cognitive network; excitatory self connections are not shown. Black arrows represent incoming signals.

Mentions: In this work, a system of 6 LV Equations (1) is studied. Figure 2 illustrates the general structure of such system with all-to-all connections among 6 modes shown in 6 different colors; external inputs are marked by arrows pointing to each mode. We are able to select the parameters of the model to guarantee the regime of regular sequential working memory. In order to produce a system having robust heteroclinic contour, the inhibitory connections are chosen in two groups, i.e., with weights greater than one and smaller than one, respectively, while the self-inhibition weights are equal to one. Moreover, the weights in each of these subsets have a limited spread, i.e., they are concentrated around a particular value. Also, the strength of the inhibition is growing when the number of interacting modes increases; for details, see Bick and Rabinovich (2010). In the pathological case of weakened inhibition, on the other hand, we may expect that the strength of some inhibitory connections to approach zero.


Robust sequential working memory recall in heterogeneous cognitive networks.

Rabinovich MI, Sokolov Y, Kozma R - Front Syst Neurosci (2014)

All-to-all inhibitory interactions between 6 modes (information items) of the cognitive network; excitatory self connections are not shown. Black arrows represent incoming signals.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231877&req=5

Figure 2: All-to-all inhibitory interactions between 6 modes (information items) of the cognitive network; excitatory self connections are not shown. Black arrows represent incoming signals.
Mentions: In this work, a system of 6 LV Equations (1) is studied. Figure 2 illustrates the general structure of such system with all-to-all connections among 6 modes shown in 6 different colors; external inputs are marked by arrows pointing to each mode. We are able to select the parameters of the model to guarantee the regime of regular sequential working memory. In order to produce a system having robust heteroclinic contour, the inhibitory connections are chosen in two groups, i.e., with weights greater than one and smaller than one, respectively, while the self-inhibition weights are equal to one. Moreover, the weights in each of these subsets have a limited spread, i.e., they are concentrated around a particular value. Also, the strength of the inhibition is growing when the number of interacting modes increases; for details, see Bick and Rabinovich (2010). In the pathological case of weakened inhibition, on the other hand, we may expect that the strength of some inhibitory connections to approach zero.

Bottom Line: As a result, competitive network dynamics is qualitatively altered.The results are interpreted in the context of the winnerless competition principle.We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions.

View Article: PubMed Central - PubMed

Affiliation: BioCircuits Institute, University of California San Diego La Jolla, CA, USA.

ABSTRACT
Psychiatric disorders are often caused by partial heterogeneous disinhibition in cognitive networks, controlling sequential and spatial working memory (SWM). Such dynamic connectivity changes suggest that the normal relationship between the neuronal components within the network deteriorates. As a result, competitive network dynamics is qualitatively altered. This dynamics defines the robust recall of the sequential information from memory and, thus, the SWM capacity. To understand pathological and non-pathological bifurcations of the sequential memory dynamics, here we investigate the model of recurrent inhibitory-excitatory networks with heterogeneous inhibition. We consider the ensemble of units with all-to-all inhibitory connections, in which the connection strengths are monotonically distributed at some interval. Based on computer experiments and studying the Lyapunov exponents, we observed and analyzed the new phenomenon-clustered sequential dynamics. The results are interpreted in the context of the winnerless competition principle. Accordingly, clustered sequential dynamics is represented in the phase space of the model by two weakly interacting quasi-attractors. One of them is similar to the sequential heteroclinic chain-the regular image of SWM, while the other is a quasi-chaotic attractor. Coexistence of these quasi-attractors means that the recall of the normal information sequence is intermittently interrupted by episodes with chaotic dynamics. We indicate potential dynamic ways for augmenting damaged working memory and other cognitive functions.

No MeSH data available.


Related in: MedlinePlus