- Poster Presentation
- Open Access
Role of three key developmental variables in the emergence of long-range temporal correlations in a network of spiking neurons without plasticity
- Nicholas Ward1,
- Simon F Farmer2 and
- Luc Berthouze1Email author
https://doi.org/10.1186/1471-2202-11-S1-P29
© Berthouze et al; licensee BioMed Central Ltd. 2010
- Published: 20 July 2010
Keywords
- Synaptic Connection
- Inhibitory Neuron
- Detrended Fluctuation Analysis
- Excitatory Neuron
- Conduction Delay
Neuronal avalanches in cortical slice cultures display statistical properties expected from a network operating at “criticality”, i.e., an optimal state for input processing [1]. It has been suggested that balanced excitation and inhibition establishes criticality, and that this state is homeostatically regulated during development [2]. Here, we systematically characterized the behavior of a network of spiking neurons without plasticity when exploring three key variables of development: ratio of excitatory to inhibitory synaptic connections, range of excitatory conduction delays, number of synaptic connections.
We simulated a network of 1000 randomly connected neurons, with a variable ratio of excitatory neurons to inhibitory neurons (N E / N I ). There were k outgoing synaptic connections per neuron, and no self-connections. The synaptic weights were fixed throughout. Inhibitory neurons only connected to excitatory neurons. Conduction delays were drawn from a uniform distribution [1,d max ]ms for excitatory neurons, fixed for inhibitory neurons (1ms). Each neuron was governed by Izhikevich’s approximation of a Hodgkin-Huxley-type neuronal model [3] such that excitatory neurons approximated cortical pyramidal neurons exhibiting regular spiking firing patterns and inhibitory neurons corresponded to cortical interneurons exhibiting fast spiking firing patterns. The network was jump-started at t=0 by a single large injection of current.
Regimes as a function of excitation/inhibition ratio, range of conduction delays and number of synapses.
Consistently with predictions, non-trivial scaling exponents were only observed in a narrow range of ratio of excitation to inhibition. Deviations from this range either led to extinction of the activity or a regime largely dominated by fast-spiking oscillations (saturated regime). These results can be interpreted within the framework of branching processes, with LRTCs occurring when the branching parameter σ~1, extinction when σ<1 and indefinite propagation of activity in the form of saturated oscillations when σ>1.
Authors’ Affiliations
References
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This article is published under license to BioMed Central Ltd.
