Computational Modeling of Single Neuron Extracellular Electric Potentials and Network Local Field Potentials using LFPsim

Abstract

Local Field Potentials (LFPs) are population signals generated by complex spatiotemporal interaction of current sources and dipoles. Mathematical computations of LFPs allow the study of circuit functions and dysfunctions via simulations. This paper introduces LFPsim, a NEURON-based tool for computing population LFP activity and single neuron extracellular potentials. LFPsim was developed to be used on existing cable compartmental neuron and network models. Point source, line source, and RC based filter approximations can be used to compute extracellular activity. As a demonstration of efficient implementation, we showcase LFPs from mathematical models of electrotonically compact cerebellum granule neurons and morphologically complex neurons of the neocortical column. LFPsim reproduced neocortical LFP at 8, 32, and 56 Hz via current injection, in vitro post-synaptic N2a, N2b waves and in vivo T-C waves in cerebellum granular layer. LFPsim also includes a simulation of multi-electrode array of LFPs in network populations to aid computational inference between biophysical activity in neural networks and corresponding multi-unit activity resulting in extracellular and evoked LFP signals.

Multiscale dynamics and information flow in a data-driven model of the primary motor cortex microcircuit

“…We simulated recording of local field potentials (LFPs) in the model. LFP signal was calculated by summing the extracellular potential contributed by each segment of each neuron (see Methods for details) 107 . LFP revealed physiologically-realistic oscillations in delta (0.5-4 Hz) and high beta to low gamma (25-40 Hz) ranges across layers and populations (Figs.…”

“…The NetPyNE tool also includes the ability to simulate local field potentials (LFPs) obtained from extracellular electrodes located at arbitrary 3D locations within the network. The LFP signal at each electrode is obtained using the "line source approximation" 107,19,77 , which is based on the sum of the membrane current source generated at each cell segment divided by the distance between the segment and the electrode. The calculation assumes that the electric conductivity and permittivity of the extracellular medium are constant everywhere and do not depend on frequency.…”

Understanding Cerebellum Granular Layer Network Computations through Mathematical Reconstructions of Evoked Local Field Potentials

“…Extracellular potential generated from a granule neuron with dysfunction showed failed and delayed response. LFP reconstructed from the circuit model with dysfunction showed distorted TC waves, attributing ionic currents to the generation of LFP [29,37] and suggest that dysfunction at individual neurons in the network reflected in the population response. The study also revealed the effect of dysfunction at single neuron in population code attributing observations on circuit behaviour.…”

“…The total LFP was calculated as linear sum of individual node LFPs. On-the-fly implementation of LFP modelling schema effectively reduced the storage space [37] . All LFP traces were averaged traces from 15 simulation runs.…”

“…Cerebellar granular layer is densely packed with granule neurons [35] and high extracellular resistance was assumed for the neuropil, modelled as isotropic volume conductor, since there was no capacitive effect in the medium in the range 0-3,000 Hz [36] . From a neurite modelled as a point source, the Laplace equation was used to calculate electric potential in the extracellular medium [37] .…”