In science, it's often the most 'boring', easily overlooked factors that determine whether an experiment succeeds or fails.
A new paper reveals strong effects of body posture on brain electrical activity: Subject position affects EEG magnitudes. Just lying face-up as opposed to face-down can powerfully affect the signal measured using electroencephalography (EEG), according to Justin Rice and colleagues of New York.
Here's why: EEG uses electrodes, placed on the scalp, to measure the electrical potentials produced by brain firing.
The signal recorded depends, however, not just on the brain activity but also on the quality of the electrical conduction between the brain and the scalp: the signals have to travel through the fluids surrounding the brain, then the skull, and finally the skin, before they're detected.
EEG users sometimes think of brain-scalp conductivity as a fixed factor, that they can't control and don't have to worry about. However, Rice et ...
