A final consideration for the adequacy of the CSD is related to the properties of the recording contacts themselves. Recordings from large (mm scale), low impedance disks are integrated over the electrode surface, rendering it impossible to resolve finer details. Conversely, high impedance tips (μm scale) may inadvertently isolate unit discharges, thereby making it impossible to continuously map (or differentiate) the LFP. These considerations are also important for inferences about the recordability of the LFP at a distance, such as the presumption that high frequency activity recorded from macroelectrodes over scalp and muscles bear a simple relationship to neuronal activity recorded from subjacent intracortical microelectrodes.
