Figure 1From: To what extent is the bipolar rheoencephalographic signal contaminated by scalp blood flow? A clinical study to quantify its extra and non-extracranial components Schematic view of electrodes, positions and measurement used in the experiment. C5, C6 and Cz are the standard positions in the ten percent electrode system, and P1 to P4 are the PPG probes positions (see text for further information).Back to article page