SCP refers to Slow Cortical Potentials. The brain produces both AC signals (the kind we usually train using neurofeedback), which oscillate between positive and negative numerous times per minute. When you train a signal at 14 Hz, for example, it has 14 positive and 14 negative pulses each second, which we see on the screen as peaks and valleys above and below the baseline on the raw waveform. However, the brain also produces DC signals, which you might see when someone rolls their eyes with electrodes near the front of the head: the whole baseline of the raw waveform, including the up-and-down oscillations, rises up above the baseline and then drops back down below it for periods covering a number of peaks and valleys.

EEG pulses are produced in various parts of the brain, even though we measure them in the cortex. For example, much of the 6-8 Hz theta activity we see is actually produced in the hippocampus, and when neurons on the surface are performing memory tasks, they “tune in” to that station and pulse to its rhythm. The source of most of the very slowest pulses in the brain, including DC or SCP signals, is the brain-stem. The brain stem is the oldest and one of the most basic and critical areas of the brain. It includes, among other things, the reticular formation, which mediates arousal throughout the whole brain. It has been described as the “on/off switch for consciousness”.

We haven’t been able to train SCP with readily available software and hardware until very recently, because the signals are generally slower than 1 Hz (one pulse per second), and we can’t filter those signals. Same as we couldn’t, for many years, train signals above 35 Hz, because hardware didn’t pick up signals that fast and software didn’t have filters to pick them out.

SCP training involves training either positive or negative potentials for different tasks. It has been researched in Europe (by Birbaumer and others) for a number of years, and the results appear to be very exciting. Main areas of training have been in the area of seizure disorders and in attention disorders. It is reported to be quite easy for clients to learn and rapidly effective.

Obviously slow potentials will be very prone to artifact from eye rolls and blinks. The use of an additional sensor is one of the options for dealing with this–especially with amplifiers that are DC amplifiers. However, SCP training can also be done with AC amplifiers (just like the PET can do AC training), and the solutions to the technical problems are different.