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Proof of concept: a spatial modular small-world self-organises by adaptive rewiring

  • 1, 2Email author,
  • 1,
  • 1,
  • 2, 3 and
  • 2
BMC Neuroscience201516 (Suppl 1) :P272

https://doi.org/10.1186/1471-2202-16-S1-P272

  • Published:

Keywords

  • Connectivity Structure
  • Spatial Layout
  • Brain Connectivity
  • Cortical Connectivity
  • Information Processing Capacity
A small-world network is a network that reconciles two opposing properties, segregation and integration. It is this reconciliation that gives rise to the impressive information processing capacity of the human brain; segregation provides a platform for information processing, whilst integration provides for the fast transmission of information. However, the connectivity structure of the brain is not static [1]; it changes on multiple time-scales; on a relatively fast time-scale, synaptic plasticity takes place, whilst on a slower time-scale there is rewiring of brain connectivity through growth of axons and dendrites. This structural plasticity depends on the even faster time-scale of neural activity. But the relationship is symbiotic: patterns of synchronous activity are, of necessity, mediated by the brain connectivity structure. Gong & van Leeuwen [2] showed that rewiring of an initially random network - adaptive rewiring - in a model of spontaneous cortical activity gives rise to a particular type of network connectivity structure: a modular small-world. In order to improve the applicability of such a model to the cortex, spatial characteristics of cortical connectivity need to be respected. For this purpose we consider networks endowed with a metric by embedding them into a physical space. Such spatial constraints may represent wiring and metabolic costs in the brain. We provide an adaptive rewiring model with a spatial distance function and a corresponding spatially local rewiring bias [3].
Figure 1
Figure 1

A, Network adjacency matrix organised to optimise visual presentation of modular structure. B, Units on the sphere colour-coded to identify distinct modules.

Conclusion

The resulting rewiring scenarios showed a spatial layout of the connectivity structure, in which topologically segregated modules correspond to spatially segregated regions, and these regions are linked by long-range connections (see Figure 1, A and B). Greater realism and increased efficiency and robustness of the symbiosis of activity and structure is achieved compared to non-spatial adaptive rewiring. Thus, the principle of locally biased adaptive rewiring may explain both the topological connectivity structure and spatial distribution of connections between neuronal units in a large-scale cortical architecture.

Authors’ Affiliations

(1)
Perceptual Dynamics Laboratory, University of Leuven, Leuven, Flemish Brabant, B3000, Belgium
(2)
Department of Mathematics, University of Leicester, Leicester, LE1 7RH, UK
(3)
Saint-Petersburg State Electrotechnical University, Saint-Petersburg, Saint Petersburg, 197376, Russia

References

  1. Zhang LI, Poo MM: Electrical activity and development of neural circuits. Nat Neurosci. 2001, 4: 1207-1214.PubMedView ArticleGoogle Scholar
  2. Gong P, van Leeuwen C: Evolution to a small-world network with chaotic units. Europhys Lett. 2004, 67: 328-333.View ArticleGoogle Scholar
  3. Jarman N, Trengove C, Steur E, Tyukin I, v. Leeuwen C: Spatially constrained adaptive rewiring in cortical networks creates spatially modular small world architectures. Cognitive Neurodynamics. 2014, 8: 479-497.PubMedPubMed CentralView ArticleGoogle Scholar

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