The origin of extracellular fields and currents — EEG, ECoG, LFP and spikes

@article{Buzski2012TheOO,
  title={The origin of extracellular fields and currents — EEG, ECoG, LFP and spikes},
  author={Gy{\"o}rgy Buzs{\'a}ki and C. Anastassiou and Christof Koch},
  journal={Nature Reviews Neuroscience},
  year={2012},
  volume={13},
  pages={407-420}
}
Neuronal activity in the brain gives rise to transmembrane currents that can be measured in the extracellular medium. Although the major contributor of the extracellular signal is the synaptic transmembrane current, other sources — including Na+ and Ca2+ spikes, ionic fluxes through voltage- and ligand-gated channels, and intrinsic membrane oscillations — can substantially shape the extracellular field. High-density recordings of field activity in animals and subdural grid recordings in humans… 
ELFENN: A Generalized Platform for Modeling Ephaptic Coupling in Spiking Neuron Models
TLDR
A generalized modeling toolbox for studying ephaptic coupling in compartmental neuron models: ELFENN (ELectric Field Effects in Neural Networks), which enables the closed-loop condition to be modeled as well, in that the field potentials can feed back and influence membrane dynamics.
LFPy: a tool for biophysical simulation of extracellular potentials generated by detailed model neurons
TLDR
LFPy, an open source Python package for numerical simulations of extracellular potentials, consists of a set of easy-to-use classes for defining cells, synapses and recording electrodes as Python objects, implementing a precise biophysical modeling scheme linking activity at the cellular level and the recorded signal.
Cell type- and activity-dependent extracellular correlates of intracellular spiking.
TLDR
It is found that spiking of excitatory neurons can significantly impact the local field potential (LFP) at frequencies as low as 20 Hz, and the common assertion that the LFP acts as proxy for synaptic activity is questioned.
Multimodal Modeling of Neural Network Activity: Computing LFP, ECoG, EEG, and MEG Signals With LFPy 2.0
TLDR
The open-source software LFPy is extended to allow for modeling of networks of multicompartment neurons with concurrent calculations of extracellular potentials and current dipole moments and is shown to show strong scaling performance with different numbers of message-passing interface (MPI) processes, and for different network sizes with different density of connections.
Multimodal modeling of neural network activity: computing LFP, ECoG, EEG and MEG signals with LFPy2.0
TLDR
The open-source software LFPy is extended to allow for modeling of networks of multicompartment neurons with concurrent calculations of extracellular potentials and current dipole moments and is shown to show strong scaling performance with different numbers of message-passing interface (MPI) processes, and for different network sizes with different density of connections.
The Spiking Component of Oscillatory Extracellular Potentials in the Rat Hippocampus
TLDR
It is found that postsynaptic currents exhibit a decreasing ability to generate large-amplitude oscillatory signals at high frequencies, whereas phase-modulated spiking shows the opposite trend.
Local Field Potential, Relationship to Membrane Synaptic Potentials
TLDR
As both Vm and LFP fluctuations originate in transmembrane electric currents, it is reasonable to find at least some correlation between the subthreshold (Vm) or the suprathreshold (spiking) activity of individual neurons and the nearby LFP.
Computing Extracellular Electric Potentials from Neuronal Simulations.
TLDR
This book chapter shows how VC theory can be derived from a detailed electrodiffusive theory for ion concentration dynamics in the extracellular medium, and it shows what assumptions must be introduced to get the VC theory on the simplified form that is commonly used by neuroscientists.
...
...

References

SHOWING 1-10 OF 218 REFERENCES
Intracellular features predicted by extracellular recordings in the hippocampus in vivo.
TLDR
A large percentage of hippocampal CA1 pyramidal cells are silent in any given behavioral condition, and it is determined that a tetrode in hippocampal area CA1 theoretically should be able to record electrical signals from approximately 1, 000 neurons.
Ephaptic coupling of cortical neurons
TLDR
It is found that endogenous brain activity can causally affect neural function through field effects under physiological conditions, and extracellular fields induced ephaptically mediated changes in the somatic membrane potential that were less than 0.5 mV under subthreshold conditions.
Nonsynaptic modulation of neuronal activity in the brain: electric currents and extracellular ions.
TLDR
Field effects and ion fluctuations probably have modest effects during physiological activity but have a significant impact on epileptic seizures, and can sustain them in the absence of synaptic transmission.
The Direct Relationship between Inhibitory Currents and Local Field Potentials
TLDR
It is shown that at these times, isolated inhibitory currents from single pyramidal cells have a similarity to the extracellular signal that significantly exceeds chance, which suggests that a significant component of HFOs reflects the last act of defiance in the face of an advancing ictal event.
Transcranial Electric Stimulation Entrains Cortical Neuronal Populations in Rats
TLDR
Intracellular recordings showed that both spiking and subthreshold activity were under the combined influence of TES forced fields and network activity, suggesting that TES in chronic preparations may be used for experimental and therapeutic control of brain activity.
Interactions between membrane conductances underlying thalamocortical slow-wave oscillations.
TLDR
A coherent framework that accounts for a large body of experimental data at the ion-channel, single-cell, and network levels is suggested and physiological roles for the highly synchronized oscillations of slow-wave sleep are suggested.
Temporal integration by a slowly inactivating K+ current in hippocampal neurons
TLDR
It is reported that the delayed excitation in rat hippocampal neurons is due to a slowly inactivating potassium current, ID, which enables the cell to integrate separate depolarizing inputs over long times and makes the encoding properties of the cell exceedingly sensitive to the prevailing membrane potential.
Estimation of population firing rates and current source densities from laminar electrode recordings
TLDR
This model study investigates the validity of methods used to interpret linear (laminar) multielectrode recordings and finds the high-frequency part of the potentials (multi-unit activity, MUA) is found to scale approximately as the population firing rate to the power 3/4 and to give excellent estimates of the underlying population firing rates for trial-averaged data.
Cellular–Synaptic Generation of Sleep Spindles, Spike-and-Wave Discharges, and Evoked Thalamocortical Responses in the Neocortex of the Rat
TLDR
Findings indicate that the major extracellular currents underlying sleep spindles, HVSs, and evoked responses result from activation of intracortical circuitries, and hypothesize that the fast field ripples reflect summed IPSPs in pyramidal cells resulting from the high frequency barrage of interneurons.
Dendritic Spikes Are Enhanced by Cooperative Network Activity in the Intact Hippocampus
In vitro experiments suggest that dendritic fast action potentials may influence the efficacy of concurrently active synapses by enhancing Ca2+ influx into the dendrites. However, the exact
...
...