Key result
Computer simulations demonstrated that unaccounted-for diffusive currents in standard CSD analysis can lead to spurious current sources, which can be removed by an improved concentration-dependent estimator.
Standard CSD analysis may predict spurious current sources due to unaccounted-for ionic diffusion, which can be corrected with an improved estimator.
Current-source density (CSD) analysis is a well-established method for analyzing recorded local field potentials (LFPs), that is, the low-frequency part of extracellular potentials. Standard CSD theory is based on the assumption that all extracellular currents are purely ohmic, and thus neglects the possible impact from ionic diffusion on recorded potentials. However, it has previously been shown that in physiological conditions with large ion-concentration gradients, diffusive currents can evoke slow shifts in extracellular potentials. Using computer simulations, we here show that diffusion-evoked potential shifts can introduce errors in standard CSD analysis, and can lead to prediction of spurious current sources. Further, we here show that the diffusion-evoked prediction errors can be removed by using an improved CSD estimator which accounts for concentration-dependent effects. NEW & NOTEWORTHY Standard CSD analysis does not account for ionic diffusion. Using biophysically realistic computer simulations, we show that unaccounted-for diffusive currents can lead to the prediction of spurious current sources. This finding may be of strong interest for in vivo electrophysiologists doing extracellular recordings in general, and CSD analysis in particular.
No takes yet. Share an insight, caveat, or question.
Halnes et al. (2017) studied Extracellular potentials and current-source density (CSD) analysis. Improved CSD estimator accounting for concentration-dependent effects vs. Standard CSD analysis was evaluated on Prediction of spurious current sources and diffusion-evoked prediction errors. Computer simulations demonstrated that unaccounted-for diffusive currents in standard CSD analysis can lead to spurious current sources, which can be removed by an improved concentration-dependent estimator.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: