DC and Slow Cortical Potential Information including Protocol Designs and Research Links

DC (Direct Current) and SCP (Slow Cortical Potential) EEG with BrainMaster

BrainMaster Technologies, Inc. is pleased to announce the initial availability of software capable of recording and training DC (Direct Current) and SCP (Slow Cortical Potentials) with the Atlantis series of hardware, and the 3.2.2 version of the BrainMaster BMT (Basic Modules for Training) software¹. This capability now provides the ability to record the DC or “standing” offset potential on the active and the reference leads, and to train using the DC information, or using SCP. The Atlantis hardware includes 2 or 4 high-quality DC-sensitive EEG amplifiers, and all EEG recordings are taken internally with DC “coupling.” However, until now, the PC software has only had access to the “conventional” EEG information. The new software (and firmware) now makes it possible for the PC software to access the DC EEG data, and to use it for research in DC/SCP EEG monitoring and training. In addition to providing DC measurements, this capability also provides extended bandwidth EEG training (to 0.01 Hz), and SCP data.

The DC potential is the actual “standing” or “zero hertz” component of the EEG. Unlike the other components which all have a defined frequency range (e.g. 8.0-10.0 Hz for alpha), DC potentials are recorded with a low-frequency cutoff of 0.00000 Hz. That is, if the sensor is “sitting” at a steady offset of, say, 150 microvolts, then that signal can be recorded and trained. This capability allows the system to monitor the slow, graded changes in the brain potential, which has traditionally been very costly and difficult to achieve. The SCP potential is defined as the DC offset, but with a very slow adaptive baseline correction factor, that eliminates the need to “zero” the amplifiers (Collura et. al. 1988). SCP potentials are typically recorded with a “time constant” of about 8 seconds, providing a very slow baseline recovery, and a corresponding sensitivity to slow brain potential shifts.

DC and SCP potentials are produced predominantly by the glial cells in the brain, not the neurons. There are almost 10 times as many glia in the brain than there are neurons. Glial brain cells have been found to be closely related to overall brain activation, and are also connected with brain stability. SCP training has, for example, been found to have significant research and clinical value in studies done predominantly in Germany, by a group at Tubingen University. Laboratory results demonstrate that shifts as much as 1000 microvolts can occur, that they are related to high-level brain processes, and that they can be trained either “up” or “down.”

DC/SCP training is generally done in a monopolar fashion. In this way, the system is monitoring the shifting of the brain potential levels relative to a standard reference. This makes it possible to specifically train the potential up or down, depending on the protocol. Unlike with regular EEG rhythms, the polarity of the training is important, as it dictates whether the brain potentials will be trained in an activating, or in a de-activating fashion.  This is the approach used by the Tubingen group, and is the most precise and accurate form of DC or SCP EEG. With the use of the Event Wizard, specifically directional DC and SCP protocols can be designed with 1, 2, or 4 channels. The entire DC signal, with 0.0000 Hz as the low end, can be recorded using this approach.

BrainMaster’s DC/SCP capability can also be used to provide extended EEG frequency range in connection with bihemispheric protocols, to provide training that rewards any shift in the slow potentials, whether up or down. In these applications, both the active and the reference sensor are placed on active sites (e.g. T3 and T4), and the difference between them is used as the training signal. When a wide-band EEG channel is used as for uptraining (“go”), then any shift in the potential will cause a training reward. Training down (“stop”) in this context will train the potential to stay constant, and not to change. The most direct method to do such training is to use a standard EEG channel for the feedback, and use the BrainMaster built-in protocol processing software. This provides training using conventional protocol-based approaches, with a working bandwidth range of 0.01 to 120 Hz.

The firmware upgrade described below provides a number of significant improvements, including several types of DC and SCP related features. When used in “Full Atlantis” mode, the EEG signals normally recorded for standard EEG training will extend from the range of 0.01 to 120.0 Hz. The software and hardware filters can be used to limit this as desired. It becomes possible, in “Full Atlantis” mode, to design protocols that operate down to 0.01 Hz, and provide useful training data.

In addition to extending the range of the standard 2 or 4 channels of EEG, this upgrade provides to ability, via the “Event Wizard”, to access the DC and SCP data directly. This facilitates a variety of protocol approaches including automatic baseline correction, directional training, and complex protocols involving all 4 channels. Protocols can combine conventional EEG training including alpha synchrony, peak-performance protocols, z-score training,or LENS training, with the use of DC or Slow Cortical Potential data.

No additional equipment is necessary in order to work with DC and SCP potentials with the BrainMaster Atlantis equipment. It is necessary to use silver/silver chloride sensors, in order to achieve a valid and stable DC recording. Many types of silver/silver chloride sensors are available, including disposable EKG sensors, and disposable or re-usable plastic retainers (“blue” ones) with embedded silver chloride disks. With the use of these sensors,

This DC/SCP capability operates simultaneously with the existing Atlantis capabilities. Therefore, in addition to the DC/SCP data, the complete EEG signal, with all of its component bands and protocol processing, are still operational. The built-in continuous impedance measurement is also operational. The firmware upgrade additionally provides access to all of the impedance data. This provides the sensor impedances for all leads, both active and reference. It is therefore possible to record DC potentials, conventional EEG, and sensor impedances simultaneously, and monitor and train on any of these variables in real time.

The key to using these new capabilities is to have the Atlantis hardware programmed with the most recent (“version 23”) of the operating firmware, and to use it with the 3.2.2 software. The firmware is the program that is loaded into the BrainMaster hardware, and allows it to perform its high-speed computations. Normally, this firmware program is loaded into the hardware at the factory, and is never changed except by factor reprogramming. It is now possible, using the 3.2.2 software, to reprogram the Atlantis hardware, and enable the new features entirely through software without returning the device to the factory. Note that only more recent devices can use this capability, and some older Atlantis units will still have to be factory reprogrammed once. All future firmware upgrades are planned to use this software-based approach. Users should contact BrainMaster Technologies, Inc. and/or refer to www.brainm.com/help and www.brainm.com/kb for online information regarding this upgrade. NOTE: To use this upgrade, please contact BrainMaster Technologies, Inc. at support@brainm.com to schedule a consultation and online assistance if needed. BrainMaster will schedule a consultation with you, and arrange for this upgrade, for Atlantis 3.0 series software users. Note: Warranty / Affiliate Membership must be up to date.

¹For experimental use only.

The following links refer to published material on DC and Slow Cortical Potential Biofeedback: