Dr. Henry Mann, MD
Neurofeedback is a variant of biofeedback that focuses on manipulation of various aspects of the brain wave with classic operant conditioning procedures. With Neurofeedback we can focus on changes in amplitude, frequency, stability and such aspects of the brain wave as coherence, phase synchrony and/or comodulation. The EEG is one of those aspects of brain function that can be measured, and if it can be measured we can learn to change it with operant conditioning procedures.
The rhythmic electrical activity of the brain measured at the surface is the result of the conjoined activity of about 50 billion vertically oriented axons known as the pyramidal cells. Each one of them has anywhere from thousands to hundreds of thousands of interconnections with other pyramidal cells. With such profound interconnectivity, it must be clear that we are dealing with a system that functions electrically as a network and which has a great deal of built-in redundancy. The rhythmicity of the EEG comes from oscillating circuits that are thalamocortical and corticothalamic in nature. The basic rhythm originates in the reticular thalamic nucleus which surrounds the thalamus and sets the basic rhythms of the EEG. However, in turn, the activity of this nucleus and the thalamus is entrained rhythmically by feedback from the prefrontal cortex – without which the stimuli from the thalamus would be completely disorganized and chaotic. This oscillating circuit is impacted by visual and auditory sensory input during the process of Neurofeedback so that the brain activity can be altered both in terms of the frequency of the EEG and the number of neurons that are recruited to work together in the frequency domain.
Why would we want to change the brain wave? The first study of brain function operant conditioning was conducted on cats by M. Barry Sterman. This study showed that cats could be conditioned to produce markedly increased sensory motor rhythm, or SMR, which at that time was determined to be 13 to 18 Hz activity at the sensorymotor cortex. Sterman demonstrated this, and then several years later in another study that utilized some of these cats found that the SMR-trained cats were able to resist the eptileptogenic effects of increasing doses of rocket fuel at levels twice as large as those tolerated by a different group of cats that had not received SMR training. The cats which did not get SMR training were apt to die of severe seizure activity while the SMR cats tolerated at least twice the dose without seizure activity, even though their Neurofeedback training took place two years prior.
This finding was serendipitous, in that it simply emerged in the data analysis of a study funded by NASA to look at the pathologic effects of rocket fuel. NASA had been having trouble with rocket fuel – handlers were getting sick, some with seizures; and some astronauts were having unusual visions of extraterrestrials that were thought to be induced by vapors from the rocket fuel.
Sterman took the cat findings and extrapolated them to humans, offering victims of severe seizure disorders that had not responded to medication the opportunity to have operant conditioning of their EEG in the SMR range over the sensorymotor cortex. The results showed that many of these persons could remain seizure-free after the conditioning.
At this point, Sterman’s work was taken up by Joel Lubar, who demonstrated that individuals with attention deficit disorder (or minimal brain dysfunction, as it was called then) responded quite favorably to Neurofeedback.
Margaret Ayers then showed that persons with TBI and stroke could also benefit considerably from EEG operant conditioning, or Neurofeedback as it became known.
Since then, many other clinical groups have extended the use of NF to various clinical syndromes that previously have been the nearly exclusive domain of psychiatric medicine, such as panic and anxiety disorders, mood disorders that include major depression and bipolar disorder, sleep onset and sleep maintenance problems, migraine headaches, tic disorders, chronic fatigue and fibromyalgia [Sterman, 2002].
Other problems such as Parkinsonism, Aspergers disorder, obsessive-compulsive disorder (OCD) and autistic spectrum disorders have been successfully either treated or improved with Neurofeedback.
Attibuting such a wide variety of treatable disorders generally invokes a tremendous amount of disbelief amongst researchers and professionals. We invite you to consider that all of these clinical conditions are mediated by brain function, and can be considered to be either instabilities of the brain function, or disturbances in a set point operation of the brain’s ongoing efforts to maintain itself. By set point, we mean that the brain has certain consent operations to maintain stability of state.
The brain maintains states of mind in the domains of time and space. The states of mind that we refer to are mood, states of arousal, sleep, drowsiness, alertness, etc. When we refer to time, we mean EEG frequency, and space indicates localization of EEG activity in the brain. Frequency of brain waves determines our state of mind in the range of 1 Hz to about 30 Hz. Sleep accompanies delta activity [1-3 Hz], drowsiness and seizure activity accompany theta activity [4-7 Hz] deep relaxation and meditative states accompany the alpha rhythm [8-12 Hz], sleep initiation and calm focus accompany SMR rhythms [13-15 HZ] and focused attention and alertness accompany the beta rhythm [15-18 Hz]. Information processing occurs at a higher frequency, approximately 40 Hz.
The brain localizes function. Examples of this are that the left prefrontal area controls most of the executive functioning of the brain, while the parietal lobe manages integration of sensory inputs. The left frontal lobe mediates attention and focus, and is the center of language processing; while the right frontal lobe mediates emotional self regulation and dysregulation. The right frontal lobe tends to have more adrenergic tracts than the left frontal lobe, which tends to have dopaminergic tracts. Faulty functioning of the brain involves both disturbances in EEG frequency and location. An example of this is depression, which is associated with 1] excessive alpha activity in the left frontal lobe and/or 2] hypercomodulation between the right and left frontal lobes.
All of the examples which we have given above relate to the history of Neurofeedback as a technique to remediate pathological conditions. There is another, and somewhat parallel, path in the historical development of Neurofeedback which relates to optimization of the nervous system's functioning, which is often referred to as personal growth or, more recently, optimum performance.
At about the same time as Sterman was initiating the development of what we now call traditional Neurofeedback of pathological states with operant conditioning in the EEG ranges of SMR [12-15 Hz] and Beta [15-18 Hz], there was another group of investigators who had discovered that training in the alpha range [8-12 Hz] and theta band [4-7 Hz] produced meditative states that were both healing and attendant with metaphysical overtones, such as deep religious experiences. This model of Neurofeedback was, as you could imagine, quite interesting to a lot of people in the late 1960’s and early 1970’s.
Although the experiences which people had in training their EEG’s in these frequency domains were quite significant, the overtones did tremendous damage to the field as a whole. In general, this approach was largely abandoned except in the area of treating addictions and PTSD, where the application of Neurofeedback in the lower frequency ranges has been extraordinarily helpful. Several studies of the treatment of addictions demonstrated that augmentation of alpha and theta rhythms in addicted persons increased their capacity for recovery from severe addictions. The usual rate of recovery after inpatient treatment improved from about 25% to 75% with the inclusion of Neurofeedback in the treatment paradigm. PTSD is now regularly and successfully treated with alpha-theta training, in which trauma victims are allowed to re-experience earlier trauma in a state of profound relaxation induced by the lower frequency EEG.
What we have discussed so far is a model of treatment based on pathology. Another approach to Neurofeedback is to work towards producing optimal functioning, rather than to treat dysfunction. This has much to recommend it. The learning that has come from treatment of dysfunction can be applied to a different pursuit which, rather than the pursuit of recovery, becomes the pursuit of excellence and competence. The same techniques which enable cures from anxiety can be focused on release of anxiety leading to full involvement in performance for singers, or in greatly increased attentional abilities and coordination in athletes.