About the Brain’s Electricity
Each brain develops what we could call stable activation patterns–basically energy habits. Using the right hemisphere to do left hemisphere tasks, establishing very sensitive warning systems, locking functions together instead of letting them flow are examples of these. I believe that these energy strategies were adopted by the brain at some time of high stress often that went on for some time. They were survival strategies, and they worked. But because any chaotic energy system like the electrical brain tends to stabilize around specific patterns, the brain continues to use those strategies long after the need for them has passed, and even long after it is clear that they are counter-productive in today’s life.
Brain Electricity
Brains produce both AC and DC signals. Those at frequencies above 1 Hz (a Hertz is a positive/negative pulse, or the waveform we see that goes up above the baseline then down below it, one per second) are AC (alternating current). Anything slower than one per second is DC or direct current. Those slower pulses, or slow cortical potentials, are produced by the brain stem and are the source of Event-Related Potentials (ERP’s).
What is exciting about them, as has been shown by some solid European research over the past several years, is that by training DC, we can actually train the brainstem, which is, among other things, the “on/off” switch for arousal and consciousness. The reticular formation, a set of nuclei that runs up the center of the brain stem, literally controls arousal.
When we train we are training bio-electric activity, which is closely connected with neurotransmitter activity. There are, as you know, excitatory neurotransmitters, which tell the next brain cell in a network to fire, and inhibitory neurotransmitters, which tell the next cell NOT to fire. The neurotransmitters don’t necessarily tell brain cells to fire at a different rate.
When we use a windowed squash, for example, we do provide ceilings on much of the frequency band to nudge the brain toward lower amplitudes in those frequencies. But we leave open another area, so any neurons firing in that band are free to rise if they choose. Sometimes amplitudes in the windows rise, sometimes they fall less than the amplitudes in the squashed areas (changing their importance in the brain’s activation patterns). Sometimes they just fall with the other frequencies. Sometimes the brain refuses to accept the training challenge and nothing happens.
What the EEG Captures
The only places we can see on an EEG are areas which have pyramidal neurons instead of stellate cells. That means that we can see the cortex, the hippocampus and the cingulate. The rest is invisible (though not to magnetic readings). I don’t necessarily think that means we can’t train other areas. For example, training up peak alpha frequency certainly has an effect on the thalamus, as does training SMR in the central strip.
The EEG is a summation of positive and negative signals at one point subtracted from the summation of positive and negative signals at another point–NOT just the number at a single point. What’s more, Tom Collura and Val Brown did an excellent presentation at WinterBrain several years ago, demonstrating that the EEG we measure is primarily measured from pyramidal neurons only (they have a positive and negative end, so there is a difference in the reading at the two electrodes), and primarily measured from those that are lined up parallel to the line of measurement. If you are reading between C3 and C4, for example, neurons at Cz which are oriented across the measurement line (running, say, between Fz and Pz) will be completely invisible to the EEG. Since the cortex is a folded and crumpled sheet of columns of neurons, individual neurons and even pools of them are oriented in many different directions, so the EEG measures only a fairly small sample of those that are in the area we are measuring from.
The EEG also is made up of a lot of background noise from neurons far from the measurement sites (which is why most EEGs are fairly homogeneous). Since the brain is a volume conductor, a saline-soaked sponge trapped inside a very poor conductor, any signal anywhere in the brain can be seen most anywhere else in the brain. It will just be a lot weaker.
The bottom line is that looking at what a single neuron does can no more directly imply what we will see in a measurement of differences between two sites than looking at how one person in New York City lives can help us predict the differences we will find between New Yorkers and Atlantans.
One of the rules of NF is that if you train anywhere, you probably have an effect everywhere. Much of the signal we see in the cortex is “noise”, actually firing patterns from neurons all over the brain.
Visible and Invisible Structures in the EEG Signal
It probably would be useful to talk about visible and invisible structures. The cortex, the hippocampus (inside each temporal lobe) and the cingulate are all composed with pyramidal neurons, so they produce a signal that appears in the EEG. Most of the primary sub-cortical players (thalamas, hypothalamus, amygdala, basal ganglia, etc.) are composed primarily of stellate neurons, which don’t produce a visible EEG signal.
Obviously most of what we see in the EEG is the largest and closest-to-the-surface cortex, but in some cases it’s possible to see the “shadow” of the subcortical hippocampus or cingulate cast onto the cortex. In the TQ we assume that, if connections were properly made with the electrodes, and absent some kind of injury, F3 and F4 will be largely alike and symmetrical. Since they share a frontier at Fz, Fz should look a lot like the two sides. When it doesn’t, it is a fair bet that we are seeing the activity of the cingulate. To a lesser degree this may be true with activity seen in the temporals.
The real question, though, is whether you can tell what the thalamus, etc. are doing by looking at the EEG. You may recall from my courses that I like to say to this analogy: If I put a puppy on a table, then covered it with a blanket, you would no longer be able to see the puppy, but you could probably have a pretty good idea what the puppy was doing. In that way, we can often get a good idea what the sub-cortical puppy is doing by watching the cortical blanket.
Part of the reason for this is that many of those structures are rhythm generators. The thalamus produces slow alpha, fast alpha, slow theta and SMR in different sets of nuclei, and those frequencies are projected all over the head. The hippocampus produces the 6-8 Hz “hippocampal theta” frequency. So if we see that alpha is generally slow around the cortex, chances are that the lower energy thalamic nucleii are dominating. If we look in the sensory-motor cortex between C3 and C4, and we see high levels of slow theta and low levels of SMR, that too would suggest the thalamus was probably not doing its screening function very well. Cz is heavily connected to the basal ganglia, which are much involved in controlling physical activity (some say they compare what was actually done with what the brain expected to be done), so Cz is an excellent place to train for those kinds of issues. The amygdala, also inside the temporal lobes wrapped up with the hippocampus, seems to be visitble–or at least projectible–by looking at the temporal lobes which may themselves be enervated by the amygdala or by the hippocampus which gets heated up by an overactive amygdala.
The Amygdala is invisible to the EEG. Like most sub-cortical structures, it is made up of stellate neurons rather than pyramidal neurons. Pyramidal cells have a positive “end” and a negative “end”, so as long as they are more or less oriented parallel to the line between the two electrodes, the active electrode (seeing one end) and the reference electrode (seeing the other end) will register a difference between the potentials. Stellate neurons (and glial cells) look the same from either end, so they aren’t “visible” in the EEG.
Technically the brainstem is not made up of pyramidal neurons, so it shouldn’t appear on the EEG and hence not be trainable by feedback. Certainly some of the basic functions of the brainstem are ROM as opposed to RAM functions (if the brain were a computer) and not amenable to much change via anything I’m aware of including NF. However the brainstem does include the Reticular Formation (or Reticular Activating System–RAS), which is the on/off switch for attention and arousal. Any kind of training to activate (reduce amplitudes, shift toward faster frequencies) would presumably call on this area. And Slow Cortical Potential training has been shown to have an effect on arousal issues (when the client can learn to do it) by shifting the DC potential of the brain, which is not strictly speaking EEG and probably works directly with brainstem activation.
Deep Brain EEG Measurement
The cortex is the “bark” on the outside of the brain–about a quarter-inch thick. There is no “deep-brain cortical structure.” There are a number of structures in the mid-brain which are heavily involved in how the brain works, but there’s a problem.
EEG is produced by one (of many) type of neuron called “pyramidal”. The cortex has a high concentration of pyramidal neurons, and it is on the surface of the brain, so we can record reliable EEG from it. Sub-cortical structures, like the Amygdalae, the Thalamus, etc. are NOT made of pyramidal neurons, and they don’t produce a measurable EEG signal. There are two sub-cortical structures that include pyramidal neurons–the cingulate, which runs beneath the cortex under the midline (all the “x” sites)–and the hippocampus, the brain’s memory center, inside the temporal lobes on each side of the brain. It’s possible to see signals from those areas on the EEG.
If you want to see directly what is happening sub-cortically, you have to use MEG (magneto-encephalography) or fMRI. These do allow us to “see” subcortical areas, but they don’t have the immediacy of EEG (which literally allows us to see changes in parts of a second) and they are very large and expensive. So researchers, wanting to know what was happening sub-cortically, developed a technique called LORETA. Essentially they recorded EEG from the cortex and calculated a bunch of algorithms to “show” the sources of the EEG in the cortex. The LORETA basically can show a cool 3D image or video of what the calculations say is happening. The idea, however, that you are “training deep into the brain” is kind of silly. You are reading the EEG on the surface, and that’s all you can train.
Here’s the really interesting part. Back when I was starting as a trainer in the early 90’s, we had 1-channel amplifiers bigger than an encyclopedia volume that were pretty slow in terms of sampling rates and pretty rudimentary software, but you know what? We knew how to train the sub-cortex without LORETA and did it all the time. How is that possible? The same way people calculate sub-cortical sources today.
There’s an interesting difference between cortical and sub-cortical sources of brain activation. When you see “beta” frequencies appearing on the surface of the brain, they are local (they should appear in circumscribed areas) and they are ephemeral (they appear and disappear fairly quickly) because beta is produced by cortical neurons doing a job. In fact, they ONLY produce fast frequencies and produce when they are working. But if beta is the only frequency produced in the cortex, then what are theta and alpha and SMR and delta, etc.?
Cortical neurons in a healthy brain spend much of their time resonating to various rhythms produced from down below–like radio stations broadcasting from a single antenna that can be picked up over a wide area. For example, there are groups of neurons in the Thalamus that generate slow alpha, others fast alpha, others SMR in the sensory-motor cortex and others for slow theta. Fast theta is broadcast from the hippocampus. When cortical neurons are not working but simply resonating to these frequencies, they use very little energy and tend to have access to sub-cortical areas (responsible for emotions and memories). So what we see on the surface, the cortex, gives us a hint to what sub-cortical areas are doing.
For example, when the amygdala is strongly activated by fear or rage, the temporal lobes beneath which the amygdalae appear tend to show fast activity out of the range shown elsewhere in the EEG. When the cortex is showing lots of slow theta in the sensory-motor cortex relative to SMR, we know that the slow-theta nuclei in the thalamus are dominating the cortex, so it is less active and capable. As a result, the brain’s ability to screen and monitor background noise is limited. That theta-dominant, low SMR or beta pattern shows up in the theta/.beta ratio as an indicator of ADHD. Cz is heavily connected also to the basal ganglia, which are involved in processing motor activation when we see that pattern, so physical impulse control tends to be poor.
I like the analogy of putting a puppy on a table and covering it with a blanket. If you just watch the blanket, though you can’t see the puppy, you can make a pretty good guess at what it is doing. LORETA would be bringing an x-ray machine to see through the blanket, but that’s really kind of overkill. When you train alpha or theta or delta or SMR in the cortex, you have having an effect on sub-cortical areas, even if you don’t spend all that money to be able to see a 3D video of it.
“Hearing” the Signal
The skull is a very poor conductor of electricity; it tends to “smoosh” (to use a technical term) the EEG from a fairly broad area–about 10 square centimeters of brain surface. That’s one reason why it’s not absolutely critical to be in an exact site to train a specific area of the brain.
Also, neurons tend to work in pools (like synchronized swimmers), so we aren’t really looking at the summed results of a bunch of individual neurons but of much larger batches working together. That’s why coherence is so much stronger between two sites the closer together they are. And that’s why the likelihood of training a monopolar montage is not terribly likely to increase coherence or reduce phase angle at one site–because they are already pretty high.
An individual neuron (or neuron pool) firing doesn’t produce an amplitude (since amplitude is measured in microvolts, and voltage is a measure of the difference in electrical force between two sites), and it doesn’t produce phase (since phase is a relationship between two lines with peaks and troughs.) An individual neuron/pool just does what it does, and we apply these various measures to it in comparison with some other site.
Neurons generally have a recharge period between firings, they don’t fire consistently as fast as they can, so although a pulse may be quite short, the number of pulses per second are not in the range of hundreds of Hz.
Activation Patterns
Once again let me make a point for my own personal prejudice in training.
First, very few brains that we are likely to see in training have a problem with too LITTLE activation. A very large majority will actually reduce activation in ALL bands as they improve.
Second, when you train ANY frequency to increase amplitudes, it is very likely that ALL frequencies will increase amplitudes. When you train any frequency to DECREASE amplitudes, it’s likely that all frequencies will decrease.
Third, you are much more likely to trigger an undesired response (headache, irritability, etc.) by pushing up amplitudes in faster frequencies than by cutting off the outliers (the amplitude spikes) in any frequencies.
Fourth, the range of trainable slow frequencies are very little affected by age, whereas the definition of frequencies like SMR and beta are very much age-related; so you don’t have to fool around with frequency definitions if you stay around 2-5 Hz.
Fifth, many clients and brains are better able to do one thing than multiple things in training, especially early on.
So, why not train DOWN the percent of activity from 2-5 Hz, or just train down the amplitude in 2-5 Hz or whatever band you want to reduce?
That said, I recognize it’s not a panacea. There are some very popular and powerful up-training protocols that I use, and there are clients who respond better to protocols requiring some down/some up. But in general, I sure would START with reducing slow activity (or whatever is too active in the EEG).
Anterior Cingulate
Since the anterior cingulate is active in controlling the flow of emotional material to the prefrontal–like a mixing valve for intellectual and emotional elements in the decision-making process–when it is stressed by trying to block lots of material, it can get “hot” (Daniel Amen’s term), and this is often a period of anxiety (which precedes depression for many folks) and stress. When the cingulate (and/or adrenals) start to get tired, then the cingulate (at Fz) can begin to show slow activity and perform its function(s) less effectively. As Tom Brownback taught us, it’s the site, stupid–not the frequency. If there is excessive emotion entering the decision-making process (as there often is with depression) look at the anterior cingulate and see what’s there rather than looking for a specific frequency.
Basal Ganglia
The best connections to the Basal Ganglia would be at Cz. You won’t “see” the Basal Ganglia in EEG, since it is not made of the pyramidal cells that show up in EEG (only the cortex, hippocampus and cingulate are), so you have to go where it’s connected and train there.
Central Strip
The central strip is a very safe place to train, and it has many connections to the thalamus, which is a key center with effects throughout the brain. Remember that for many years the pioneers in neurofeedback did all training at Cz, C3, C4–and many people still do.
Cerebral Cortex
Part of the job of the cortex is to control and integrate emotional material (and memory) with sensory information to keep us alive and moving toward our objectives. When Tone issues become dominant, more of the cortical energy needs to go toward just keeping emotional drives in check, and the Tone strategies (disconnect, hot temporals, reversals and blocking) are commonly seen patterns that cortexes adopt to deal with excess emotional drive.
Cingulate Gyrus
The cingulate, along with the orbitofrontal cortex and basal ganglia, balance thought and emotion. The overactive cingulate, with lots of beta, tends to push heavy on the thought side at the expense of emotion. The underactive cingulate, with lots of alpha, tends to under-regulate the emotional side.
Remember that, to see the cingulate, you need to look for its “shadow” running under Fz, which appears most clearly when you compare it against F3 and F4.
Default Mode Network
The DFN (default mode network) is described as “what the brain is doing when it is not doing anything.” It’s the brain’s resting state.
It appears that the ability to synchronize between Fz and Pz helps to link the brain’s inner and outer awarenesses, which is a good thing.
Synchrony in theta, alpha and gamma are all commonly trained, and clients often report feeling calmer and quieter after such a session. You can train eyes closed or open.
There are many different EEG patterns that can relate to anxiety or depression or anger. You’re welcome to try training the default mode network and not worry about what else is going on in the brain, but in many clients I’ve worked with, clients don’t produce coherence between Fz and Pz, because their brains are stuck in patterns like a R/L reversal of beta or hot temporal lobes or high fastwave coherence in the frontal lobes. Some clients even show high fastwave coherence between Fz and Pz or normal levels of alpha, theta and gamma synchrony in those sites.
I’ve found it generally helpful to train the DFN as I would any other area. It depends on the client and on what is already there. As other issues start to respond, then the DFN training seems to work better as well.
Energy Patterns/Exercise Analogy
There are energy patterns that are very costly–lots of fast activity–and others that are very “cheap”–lots of slow activity.
It seems possible in some cases for a very costly pattern to “reset” itself in a single session, often an extended session to a much more sustainable level of activation. I’ve seen this happen a number of times with patterns like hot temporal lobes. In one session the client may experience a dramatic improvement that lasts for some time. Anxiety levels drop, internal chatter drops. In most of the cases I’ve seen like this though, there are other more stable patterns related to (for example) the anxiety (e.g. left/right or front/back reversals, high fast-wave coherence in the front). As the least sustainable pattern is released, over a period of time they tend to rise to the level of awareness. It’s a “different kind” of feeling of anxiety, but the anxiety strategy is still there and returns to become problematic again. Very possibly, though, the hot temporals don’t re-appear without some external stimulus.
With low-energy dominant patterns, I’ve never seen any client suddenly “wake up” and sustain it. The energy economy simply isn’t there yet to sustain it.
Exercise and Energy Patterns
Anyone can improve physical performance by doing aerobic exercise to improve heart and lung function. You don’t need a diagnosis to do it. You don’t need a physician’s order to do it. You really don’t even need a coach. You know there is a target range for your heart rate that is safe and effective, and you have ways of tracking that. If you are smart you start slow and build slowly to avoid injuries and allow your body to increase its stamina. You don’t have to think. You don’t have to try. All you have to do is exercise–as simple as walking. Two people may walk together every day; one tracks his pulse rate, number of calories burned, distance walked, average speed, etc. and keeps it in a computer file; the other just walks; they both get the same results.
It you want to improve your brain performance in general, strengthening the metabolic capacity of the PFC is a key. You don’t need a diagnosis to do it. You don’t need a physician’s order to do it. You really don’t even need a coach. You simply track infrared temperature (or a measure involving it) to keep it rising or stable until you can’t any more. If you are smart you start slow and build slowly to avoid injuries and allow your PFC to increase its stamina. You don’t have to think. You don’t have to try. All you have to do is exercise–as simple as paying attention.
Two people may train together every day; one tracks his starting and ending temperature, minutes trained, etc. and keeps it in a computer file; the other just trains; they both get the same results.
When your brain actually changes its ability to deliver greater levels of oxygenated blood to the tissues where prefrontal neurons are working, then your control center begins to work effectively and lots of stuff in your real world change. It’s that simple. It’s aerobic exercise. I know some people never go out to walk aerobically without a pedometer and pulse meter and special watch to count calories burned and average heart rate and time walked and distance. They come home and graph all that stuff and perhaps even convince themselves that without all their vigilance and tracking nothing would happen. But a friend walking beside them with no equipment, no tracking, no worries–just walking the same time at the same speed and watching the scenery will get at least as good results–maybe better, because the cardiopulmonary system (which aerobic exercise pushes instead of prefrontal perfusion as HEG does) can be the body’s focus instead of that chattering mind.
Does aerobic exercise fix all ills? Of course not. It won’t cure cancer, though it can give your body its best chance to deal effectively with most diseases. And a person with a brain activation pattern that is seriously “out of whack” (if you’ll permit me a technical term here) may not be “fixed” by HEG. However, a depressed person may get great relief by activating an underactive left prefrontal area. An anxious person may feel much calmer as he gets the right prefrontal area activated.
Hemispheric Dominance
If you are right-handed, as is roughly 92% of the population, your left hemisphere is dominant for language; right for music and emotional response. If you are left-handed, there is about an 85% chance that you’ll be the same as the righties. Roughly 1.2% of the population has brains that have organized to use the right hemisphere for language (for which it’s not as well suited) and the left for music and mood (also for which it’s not as well suited).
There are tests of dominance of sight, dominance of hearing, various tests crossing arms and folding hands, etc. that purport to tell you which of what is dominant for whatever, but people usually end up pretty split on those. There was a very good test of asking a person to (as I recall) remember something, or count backward by sevens or something where you would watch to see if the person looked up and to the left or the right that I used to use.
Looking at the EEG, if you have a lefty to train, you might look at the Theta/Beta Ratio section on the Analyze page of the TQ7. You can see if the theta/beta ratio is lower (or more in the white range) at C3 or C4, and which one best activates at task. That can be helpful in determining at least which side is working harder on a language task when one is assigned. If it really becomes a training issue, which it has twice in my career as a trainer, try reversing the training for cognitive performance and see it the response improves. If you have been training up beta at C3 and SMR at C4, reversing those may give you an idea if you should train that way. You can look at the same things in the frontal and parietal lobes. If you find the right side activating more strongly in all of them, that would be a stronger indication of right-dominance for cognitive tasks.
One of the interesting unanswered questions in NF for me is whether reversal for language has any effect on alpha and beta reversals and their relation to mood. As far as I have seen, it does not, but then, as I wrote above, I haven’t had much experience with left-handers reversed for language.
Head Injury and Dominance
If someone has a head injury of whatever sort, then the issue of hemispheric dominance would drop way down in importance as I developed a training plan for that brain. Obviously if you chop off a right-hander’s right hand, he probably won’t be a right-hander any more. The issues of hemispheric dominance are important absent more foundational issues.
Mixed/Incomplete Dominance
Remember also that there are several different conditions related to dominance. There is clear left dominance related to language tasks, which is by far the most common condition. There is clear right dominance related to language tasks, which is fairly rare and seems to be limited to clear left-handed people. There is also mixed or cross or incomplete dominance. This is a lack of complete organization in the brain, and it shows up in a high percentage of people with Filtering problems. The client will tend to do some things left-handed and others right-handed. It may or may not be clear in the EEG in various areas. Some people test for multiple indicators of dominance (eye, hand, finger, arm, foot, etc.).
The Othmers did a study back in the 90s (never published, to the best of my knowledge), when they still admitted they didn’t know much about what was happening in the brain, that was very interesting. They measured everything they could think of in a group of ADHD children, then trained them, then measured everything again to see what would change. They found something like 50% right-handed, 30% left-handed and 20% mixed dominant using the “tapping test of lateral dominance”. After training (not doing anything at all to change handedness), they reported that they now had 85% right-handed, 15% left-handed and no mixed dominant. Not only had all the mixed clients organized to one side or the other, but a bunch of the lefties became righties!
Eye-Movement Test for Dominance
One of my favorites of these tests is the “conjugate lateral eye-movement” test, which is also neurologically based.
Sit facing the client and give him/her a moderately challenging mental math problem to perform (don’t make eye contact). Watch for movement of the eyes, which should go either left or right, when the client is performing the task. Repeat several times (I like to do this during the parietal assessment challenge task). If the eyes consistently move to the right, the client is using left hemisphere for math calculation. If the eyes move consistently to the left, the client is using the right hemisphere. There is a very high correlation between dominant hemisphere for calculation and for language. Some clients shift back and forth, which indicates mixed or incomplete dominance. My favorite client of all time in this test went left..then went right..then up…then rolled her eyes in a complete circle. I have no idea what that meant.
It is important not to make the task “impossibly” difficult in the client’s mind, or you’ll get no movement at all.
Normal Brains and Set Points
The brain is a very complex chaotic system made up of billions and trillions of networks which are linked in feedback loops to create a fairly stable structure. Same way your weight tends to stay fairly stable over long periods, regardless of exercising a lot one day, eating a lot another. Systems theory tells us that such systems tend to have stable operating points called attractors or set points. When we go on a concerted diet change or exercise change over a period of time, we literally move our body’s metabolic system from one set point to another and (hopefully) stabilize it there. When we do a series of brain training sessions, we are (I believe) moving our brain systems from one set point to another better able to perform the tasks we want to be able to perform.
Placebos and Results
The Tao that can be told is not the eternal Tao; the name that can be named is not the eternal name.
LOTS of stuff works that we can’t explain exactly; in fact MOST of what works we CAN’T explain logically. You can choose, in those cases, to refuse to do those things because they might be placebos, or you can do them and get results.
Because you can’t explain how a particle can be in two places at the same time, or how measuring something changes it, doesn’t necessarily mean it’s not true, and refusing to accept it because it can’t be explained logically cuts off a whole area of particle physics. Stick with Newton and ignore Einstein. How can you explain how a team of inexperienced and perhaps less talented players can win a championship over a highly-paid team of superstars with incredible talent and much more experience? Logically it can’t happen. It just does. I’ve never seen a plausible explanation of why a person can’t ride a bike and then suddenly can, but it’s happened to all of us. How do you explain brilliant flashes of creativity that solve a problem that logic didn’t solve? If you’ve missed that experience, you’ve missed an amazing part of being human.
If I’m a researcher, then I have committed my efforts to parsing things down into smaller and smaller pieces so I can use the kind of thought you are talking about to prove that something happens because of something else–though I’ll never actually publish my results without including the statement that this requires further study to make work for more researchers.
If I’m a trainer trying to guide people’s efforts into areas that will help them change their lives, their moods, their capacities, etc., I don’t care so much about proving WHY something happens. It’s enough for me that it does with some reliability, because I don’t care about answers, I care about results.
Pre-Frontal Cortex
The pre-frontal is the part that lies behind the forehead. Everything from the central sulcus, which runs from ear to ear across the middle of the central sensory motor strip, to the very front of the head is frontal lobes–about half the cortex. The PFC is the executive center of the brain, so it controls attention, screening of distractions, processing of sensory information, organizing, planning, short-term working memory, impulse control (verbal, physical, emotional) and (on the left) language output. Training to improve its function is often very effective in improving these issues and maturing the brain (i.e. speeding it up), just as changing the CEO of a company can improve functions throughout the company. Training in the PFC is relatively impossible with EEG, since on the forehead the EEG picks up signals from facial muscles, eye muscles and the eyes themselves which appear in the EEG though they are not from the brain, so it’s better to train using HEG.
Just as doing aerobic exercise doesn’t mean that a person HAS TO run all the time and stay in a high-energy state, so improving the capacity in the PFC doesn’t mean that it MUST be highly activated. It’s capacity that’s being trained.
Sense of Smell
The rhinencephalon, where the sense of smell is located is actually in the limbic system in the center of the brain. I’m not aware of any cortical area that handles smell. That does suggest that perhaps the temporal lobes, which are strongly connected to the limbic system, may be a good place to train.
Skull Thickness
I’ve heard from a number of folks who are experts in EEG that the single factor that accounts for about 85% of overall differences in absolute EEG amplitudes is thickness of the skull. If your low amplitude client is an adult and your others are children, that explanation could make even more sense. But the reality is that some people just have thick skulls.
Slow Cortical Potentials
Slow Cortical Potentials are signals that go down as low as 0.3 Hz. They represent Direct Current (DC) activity in the brain, so they do not, in fact, ever “shut off”. Studies by European researchers over the past 10-15 years have shown that shifts in one direction improve sensorimotor function (especially useful with seizure issues) and in the other direction affected cognitive performance.
Unfortunately these review articles don’t get very specific about how slow is slow, but the SCP activity ranges down to about one shift every 3 seconds. The current Othmer training approach would be one shift about every 3 1/2 minutes.
Theoretical Musings
Doubtless most of us on the list have heard so many times that we believe it’s proven that NF is conditioned response. In that frame of reference, then all the stuff about rewarding becomes important.
However, systems as complex as the nervous system are almost certainly organized around principles of oscillatory “ordered chaos,” rather than being neat, linear systems (linear in both a mathematical and a metaphorical sense). Thus, neurofeedback may be as much about resetting equilibrium points in the dynamic chaos of functional neurological systems as it is about teaching certain groups of neurons (visualize students sitting in neat rows in a classroom) to behave better. Obviously, it’s easier for us to think in linear terms (e.g. linear algebra versus partial differential equations), but that doesn’t mean that the brains that do that thinking are linear oscillatory systems. The random inputs that brought order to the oscillating pendulums did not “teach” the pendulums how to be more orderly. Instead, the random inputs induced a change of state in that oscillating dynamic system. The pendulums didn’t “learn” to “behave” better (B.F. Skinner notwithstanding), they were simply put into a different form of functional chaos (to the pendulums either functional mode–“chaotic” or “ordered”–was still just a state of chaotic motion) by particular external inputs. All that I am suggesting is that we might be doing something similar with neurofeedback: not so much “teaching” the brain to “behave” better as cajoling it into different states of chaotic equilibrium—like changing the dynamic pattern on an oscillating membrane (e.g. Richard Feynman’s conga drums).
I believe neurofeedback is like exercise. In most exercise we have some form of mirror: you might be watching yourself trying to achieve and stay in a pose in yoga, or have a pulse-meter that informs you when you are in or out of the training range in aerobics. There’s nothing innately reinforcing about the pulse meter or even looking at yourself in a mirror or noticing how many pounds you are lifting and how many times. They are ways of helping the brain recognize that it is moving in a desired direction. I suppose you could argue that a pulse meter beeping when you are above or below the aerobic training range is conditioning a response, but maybe it’s just telling you to speed up or slow down when you are walking on a treadmill.
Per the conditioned response literature, positive feedback is much more powerful than negative, and continuous is more powerful than contingent. However I often use “negative” feedback when training a client during task–a tone that plays like an alarm when the client’s theta (for example) rises above target and silence when it is within range. It has worked very well. And I’m a strong believer that the type of feedback (continuous or contingent) should be related to the type of exercise we are asking the brain to do. Activating (aerobic) seems to work best with contingent (on/off) feedback. Continuous feedback works better for brain yoga/stretching (de-activating). I have no idea, if NF is conditioned response behaviorism, why this would be true, but it makes a lot of sense if training is brain exercise. Even the issue of how long to train in a segment fits with exercise. If you are trying to build stamina with aerobics or weight training, you use shorter sessions of pushing your limits separated by breaks (like wind-sprints). If you are trying to release something that is too tight, you use longer, slower training segments and let the unwinding happen little by little.
The nice thing about this approach is that you don’t have to worry about whether the feedback is intrinsically rewarding or not (so you don’t need different feedback for each client). It is, as someone suggested in a previous post, and I have long said) simply a mirror.
Classical and Operant conditioning are two concepts that behavioral psychologists use to explain what happens from their point of view. Their point of view is far from the only one–or even the best one–but since most literature about NF has been written by psychologists–and most of them are trained behaviorally–pretty much any article you read about NF will start off by taking as a given that training is “operant” conditioning. NOT classical. It’s a handy shorthand that underlies the concept that NF is a psychological intervention rather than something we do for ourselves. But it is far from being proven.
First, what is classical conditioning? Pavlov’s dogs who salivated at the sound of a bell. It involves placing a “neutral” stimulus BEFORE a REFLEX. A hundred years ago John Watson used a hammer to bang a metal pipe, thus producing a fear response in a baby boy who was not previously afraid of small furry animals. After doing this often enough–hey, this was Science, so it was okay–he managed to get the little child to cry in fear whenever any furry animal was presented to him. That’s certainly worth doing. Save a lot of money on pet food over the years. CC is reportedly useful in desensitizing or flooding to extinguish a fear response, though after a century it’s still not a primary approach. Supposed to be good in smoking cessation or intervening in alcohol abuse, though again, I’m not sure how often it’s used. Instead of making you vomit when you take a drink, brain training changes the personality significantly (and painlessly) enough that the compulsion to drink is no longer there–not simply scared away.
In any case CC is pretty far from what we do in brain training, where we provide FEEDBACK–not a neutral stimulus–AFTER the brain does something. Unless you worked pretty hard to play a certain note over and over just before the brain produced a burst of SMR, for example, it’s unlikely there would be much of an effect.
Operant conditioning (OC) is a bit different. It involves rewarding or punishing AFTER a VOLUNTARY behavior to reinforce or extinguish it. Teach a pigeon to peck a button by giving it food every time it pecks a red light–not a green light. Or Barry Sterman provides sweetened milk drops to cats whenever they produce a burst of SMR above a certain level.
If you are a hungry pigeon or cat, some bird seed or sweet milk is pretty obviously a reward, whereas, for example, some beeps from a computer, or momentary darkening of a screen may not be so clear. It raises the questions that have been discussed here in the last couple days–does the client “LIKE” the feedback? It would seem that, in the case of the client who had the bad headphones, the training should have REDUCED the level of the desired behavior, instead of increasing it as it apparently did!
Another problem–one raised by Sterman himself–has to do with the discreteness of the event and the feedback. Since bursts of, say, SMR are being produced multiple times per second–among many other types of activity–how exactly does the brain know which event is resulting in the reward? Sterman made quite a point a number of years ago of telling trainers they needed to give a recharge period after each reward. Feedback had to be intermittent rather than continuous. After a burst of SMR over threshold and production of a reward, you had to stop giving feedback for a time and then start again looking for the SMR burst. It was pretty cumbersome way of training, though (since it was Sterman telling us to do it) more than a few people went to the trouble of trying to produce designs that more or less met the requirements. To the best of my knowledge people working with clients didn’t didn’t notice any particular improvement in their clients’ ability to produce SMR–much less their ability to relax physically, so it’s pretty rare to find anyone still trying to do this.
Maybe behavioral psychology’s attempt to cast NF in its own image requires some pretty major leaps of faith to make any sense. But gosh, if brain training ISN’T OC, then what could it possibly be?
What if brain training isn’t psychology? After all, it works with spiritual and physical as well as mental and emotional issues. What if it isn’t about fixing mental disorders but about moving toward greater flexibility and range. Is meditation psychology? Are brain exercises like Lumosity psychology? What if brain training isn’t about “conditioning” the brain in some kind of mechanistic way but instead is about giving it greater control instead of less?
The hint is in the name: Feedback. One way we learn to control ourselves is by using mirrors. We do something and the feedback shows us HOW well. It seems kind of simple, but the reality is that the human brain learns most everything from mirrors. It responds to sensory inputs by taking action, then it sees what happens. Feedback. That might help explain Birgit’s client’s positive response to unpleasant feedback. Even if I don’t LIKE what I see in the mirror, I can still learn from it. And taking the mirror home and looking into it when you aren’t trying to do anything isn’t likely to be terribly produtive.
It might also explain why someone doesn’t get a response when they focus on the entertainment value of the feedback instead of seeing themselves reflected there. Don’t pay attention to the feedback, it’s of less benefit.
I don’t care whether you think the behavioral psychology model is more useful or the feedback/mirrors model, or just an “exercise” model. It means almost nothing if your main focus is on guiding a client to produce changes. I just hate to have us tossing around concepts like “conditioning”–which suggest that something is being done TO us–without really thinking about them. Exercising in front of a mirror is something we do FOR ourselves. I like that approach much better.
White Matter
White matter is the myelinated axons that connect neurons. Usually axons are still in the process of becoming myelinated (which allows them to fire faster) during the age period you mention, so I guess that “over” growth would mean that the neurons get myelinated too fast and the brain begins to shift to faster frequencies earlier. I guess that might be consistent with the symptoms people call Asperger’s and autistic spectrum, since they often show lots of fast activity. However, saying that both happen to co-exist is a long way from saying that one causes the other. And I would expect that if that were a problem, we’d see it in a lot broader area than that little strip from C3 to T3. And I’d expect to see higher Z scores in the fast frequencies than the image you provided.