10. Sleep and Fatigue . Inadequate testosterone can also lead to poor sleep quality, which means that the only thing you'll want to do under the covers is put your head on the pillow and crash. Testosterone deficiencies decrease the all-important recuperative REM sleep and other critical sleep parameters. One study showed that low T did this not only by increasing weight gain, which negatively impacts sleep in and of itself, but also through other mechanisms that we do not yet understand.  And none of this should be a surprise considering how much that testosterone affects the brain.
Electrode locations and names are specified by the International 10–20 system  for most clinical and research applications (except when high-density arrays are used). This system ensures that the naming of electrodes is consistent across laboratories. In most clinical applications, 19 recording electrodes (plus ground and system reference) are used.  A smaller number of electrodes are typically used when recording EEG from neonates . Additional electrodes can be added to the standard set-up when a clinical or research application demands increased spatial resolution for a particular area of the brain. High-density arrays (typically via cap or net) can contain up to 256 electrodes more-or-less evenly spaced around the scalp.