Volume 12 Supplement 1

Twentieth Annual Computational Neuroscience Meeting: CNS*2011

Open Access

Network inhomogeneity supports burst initiation in vitro

  • Samora Okujeni1, 2, 3Email author,
  • Nila Moenig2,
  • Steffen Kandler1, 2, 3,
  • Oliver Weihberger1, 2, 3 and
  • Ulrich Egert1, 3
BMC Neuroscience201112(Suppl 1):P84

DOI: 10.1186/1471-2202-12-S1-P84

Published: 18 July 2011

The emergence of spontaneous bursting events in developing neuronal networks likely depends on the evolving network connectivity. Theoretical models have shown that hierarchical network structures embedding clusters of strongly inter-connected neurons are optimal for initiating and sustaining spontaneous activity [1]. It is conceivable that activity-dependent wiring could innately support the formation of similar network structures.

To test this we chronically manipulated activity-dependent structural plasticity by inhibition of protein kinase C (PKC) in developing networks of cortical neurons in vitro. Previous studies showed that PKC inhibition in developing cerebellum promotes dendritic outgrowth and arborization of Purkinje cells and impairs pruning of climbing fibers. We found that developmental inhibition of PKC in cortical cell cultures increased dendritic outgrowth, impaired neurite fasciculation and clustering and abolished network pruning. This resulted in more homogeneous and potentially better connected networks (fig. 1A-B). As a result, propagation of activity within bursts was faster and occurred in strongly isotropic waves (fig. 1C-D). Interestingly, bursts in these networks were triggered from fewer sites and at much lower rates suggesting that the homogeneous networks forming under blockade of activity-dependent wiring processes embed fewer burst initiation zones.
Figure 1

MAP2 staining of dendrites and somata: control networks (A) display characteristic features of an activity-dependent wiring process including fasciculation and ramification of dendrites within clusters. Developmental inhibition of PKC (B) generates more homogeneous networks in which neurites grow out ignoring neuronal neighbors. Propagation of activity in spontaneous and stimulation-induced bursts was analyzed in micro-electrode recordings (first spike rank order from light to dark gray; black: no activity; white circles indicate stimulation sites): bursts in control networks (C) display irregularities in the spatial propagation pattern indicating complex underlying structure. Homogeneous networks developing under impaired PKC activity (D) show highly isotropic propagation patterns. Spontaneous (E) and elicited (F) propagation patterns in controls are hardly comparable. Stimulation of homogeneous networks elicits highly isotropic propagation patterns (H) similar to those in spontaneous bursts (G). Scale bars: 2mm.



Funded by the German BMBF (FKZ 01GQ0420 & FKZ 01GQ0830) and by the EC (NEURO, No. 12788)

Authors’ Affiliations

Bernstein Center Freiburg, Univ. Freiburg
Fac. Biol., Univ. Freiburg
Fac. Engineer. – IMTEK, Univ. Freiburg


  1. Kaiser M, Hilgetag CC: Optimal hierarchical modular topologies for producing limited sustained activation of neural networks. Front Neuroinf. 2010, 4 (8): 8.Google Scholar


© Okujeni et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.