" ... Here, we performed a detailed investigation of the frequency dependence of the conductivity within cortical tissue at microscopic distances using small current amplitudes within the typical (neuro)physiological micrometer and sub-nanoampere range. We investigated the propagation of LFPs, induced by extracellular electrical current injections via patch-pipettes, in acute rat brain slice preparations containing the somatosensory cortex in vitro using multielectrode arrays. Based on our data, we determined the cortical tissue conductivity over a 100-fold increase in signal frequency (5-500 Hz). Our results imply at most very weak frequency-dependent effects within the frequency range of physiological LFPs. Using biophysical modeling, we estimated the impact of different putative impedance spectra. Our results indicate that frequency dependencies of the order measured here and in most other studies have negligible impact on the typical analysis and modeling of LFP signals from extracellular brain recordings."
Model Type: Extracellular; Neuron or other electrically excitable cell
Cell Type(s): Neocortex L5/6 pyramidal GLU cell
Currents: I Na,p; I Na,t; I L high threshold; I A; I h; I K,Ca; I Calcium; I A, slow
Model Concept(s): Extracellular Fields; Methods; Simplified Models; Detailed Neuronal Models
Simulation Environment: Python; NEURON
References:
Einevoll GT, Ness TV, Miceli S. (2017). Impedance Spectrum in Cortical Tissue: Implications for Propagation of LFP Signals on the Microscopic Level Eneuro. 4