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This article is part of the supplement: Eighteenth Annual Computational Neuroscience Meeting: CNS*2009

Open Access Poster presentation

Inclusion of noise in iterated firing time maps based on the PRC

Fred H Sieling1*, Carmen C Canavier2 and Astrid A Prinz13

Author Affiliations

1 Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA

2 Neuroscience Center for Excellence and Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA

3 Department of Biology, Emory University, Atlanta, GA, 30322, USA

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BMC Neuroscience 2009, 10(Suppl 1):P345  doi:10.1186/1471-2202-10-S1-P345

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2202/10/S1/P345


Published:13 July 2009

© 2009 Sieling et al; licensee BioMed Central Ltd.

Poster presentation

Methods using the phase response curves (PRCs) of component neurons to predict network activity suffer from biological variability intrinsic to the studied neural oscillators, often described as noise. To make analytical predictions, researchers minimize this noise either by averaging the measured PRC or by controlling the period of oscillation. Here, we present an alternate method that incorporates measured noise into PRCs. In a hybrid network of two bursting neural oscillators coupled via synaptic excitation (tsyn ≈ 10 ms), we found that this method could accurately predict phase locking in the presence of variability in the intrinsic period of 10%.

We modeled our hybrid networks using the experimentally obtained PRCs of component neurons as well as their noise envelopes. We represented the first and second order PRCs (F1 and F2)

where σ was the standard deviation of the experimental PRC as a function of stimulus phase ψ on the interval (0,1), X was a normally distributed random variable with mean 0 and standard deviation 1, and PRCfit indicates a polynomial fit of the experimental PRC. PRCs are defined as in [1]. For each component neuron j, interburst intervals (IBI) were calculated iteratively according to a modified Winfree model [2]

where P0 is the intrinsic period, fj, k [n] is the phase at which neuron j receives the kth input in the current cycle, and fj, l [n-1] is the phase at which the lth input was received by neuron j in the previous cycle. We defined time of input as the start of a burst in the presynaptic neuron. To simulate a reduction in the overall amount of noise in the system, we scaled the noise envelope by a factor less than 1. The inclusion of noise in the PRC-based iterative map is similar to those of [3]; the major difference is the use of F2 in addition to F1 in our method.

We compared experimental observations to predictions made using a noiseless model of pulsatile coupling [4] and to the predictions of our iterated map. Out of 86 networks tested [5], the noiseless model was incorrect 16 times and the iterative map was able to make the correct prediction for 12 of those networks. Further, the success of the iterative map method was predictable by inspection of the PRCs and noise envelopes.

References

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  4. Oprisan SA, Prinz AA, Canavier CC: Phase resetting and phase locking in hybrid circuits of one model and one biological neuron.

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