Power Laws from Linear Neuronal Cable Theory: Power Spectral Densities of the Soma Potential, Soma Membrane Current and Single-Neuron Contribution to the EEG
Figure 1
Schematic illustration of the input-output relationship between transmembrane currents (input) and the different measurement modalities (output).
The transmembrane currents are illustrated by synaptic currents and channel currents. A synaptic current is commonly modeled by means of exponentially decaying functions (synaptic kernel) triggered by incoming spike trains, whereas a channel current typically is modeled by a channel switching between an open state (o), letting a current with constant amplitude through the channel, or a closed state (c). The input currents are filtered by the neuronal cable, resulting in a low-pass filtered output current in the soma with a power spectral density (PSD) designated . The PSDs of the other measurement modalities studied here, i.e., the soma potential (
) and the current-dipole moment giving the single-neuron contribution to the EEG (
), are typically even more low-pass filtered, as illustrated by the PSDs plotted in the lower right panel.