By Interactive Metronome - June 30, 2014

It All Matters: White Matter and You

Your brain is composed of two basic substances, grey matter and white matter. Many researchers believed that grey matter’s role in language, memory and emotion made it more important, so they neglected white matter for hundreds of years. For centuries, white matter’s role in brain communication was not only mysterious, but considered relatively unimportant. Solve a problem with grey matter and you solve the problem with the brain. Well, that is wrong…very wrong.

White matter tracts are responsible for the communication between the brain’s functional networks. That should come as no surprise considering that white matter is mostly composed of axons and myelin sheath, essentially wiring and its insulation. The grey matter may initiate a good deal of the processing tasks, but white matter makes sure those orders are carried out. In fact, the corpus callosum, the largest white matter tract, is what connects the right and left hemispheres of the brain.

However, it goes beyond the corpus callosum. White matter connects all four of the brain’s lobes and every defined brain region. Dr. Christopher Filley, professor of neurology and psychiatry at the University of Colorado Medical School, says, “This suggests that the cortical regions act in concert to perform mental operations and no cortical area acts in isolation. Without functioning white matter, the brain could be like a group of people in proximity to each other but unable to communicate with each other.”

As we said in our earlier piece on brain timing and processing speed, the brain is organized in an unlimited amount of functional networks. The white matter is what allows these networks to act in concert. White matter tracts run up and down, left and right, and to every functional part of your brain (even some not so functional).

Three types of white matter tracts are responsible for bearing the load. Projection tracts are the vertical tracts that connect to the spinal cord and cerebrum. This white matter is what moves the signal out of the brain and on to the body, making it incredibly important for coordinating movement and responses. The white matter than runs left to right between the hemispheres, running through the corpus callosum and the smaller anterior and posterior commissures, are the commissural tracts. The major function of these is exactly what their placement would suggest; they connect the right and left sides of your brain, the creative and the practical. Finally, association tracts run all throughout their own hemisphere. These are really the runners between your brain’s functional networks because they help link up your memory and processing centers in the grey matter. Fortunately, these are the easiest to bypass in case of damage, meaning that alternative routes can form after we relearn tasks over time.

With all we know now, it is surprising that science neglected white matter for hundreds of years. Even with the crude medical technology of the past, researchers clearly saw that the differences in the brain’s structure. The anatomist Andreas Vesalius distinguished between white and grey matter in 1543, in the seventh book of his masterpiece De Humani Corporis Fabrica, meaning neuroscientist have only been studying half of the story for a quite some time.

Nonetheless, over 300 years later, the French neurologist Jean-Martin Charcot began to illustrate the importance of white matter in his work. Often known as “the Napoleon of the neuroses,” Charcot was determined to understand the workings of the brain. His research is responsible for much of our early understanding on multiple sclerosis (MS), Parkinson’s disease, amyotrophic lateral sclerosis (ALS, or Lou Gehrig disease) and a variety of hysteria and movement disorders that have since be renamed or categorized.

Understanding conditions like MS, Sensory Processing Disorder (SPD), ALS, dyslexia, autism spectrum disorder (ASD), dementia and Parkinson’s has been a major catalyst in brain research. As Dr. Kevin McGrew, Director of the Institute for Applied Psychometrics and co-author of the Woodcock-Johnson Battery III and IV, says in his recent blog, “White matter matters: Brain synchronization via the brain’s communication subway system”:

Research during the past decade has implicated white matter as performing the critical task of connecting and synchronizing different brain regions or networks so they can perform a wide variety of complex human cognitive or motor behaviors. The white matter system is considered the communication backbone system for the flow of information in the brain … White matter integrity or dysfunction as been implicated in a wide variety of cognitive disorders or abilities, including cognitive control, math and intellectual giftedness, fluid intelligence or reasoning, processing speed, reading, decrease in cognitive functioning, meditation, working memory, vascular cognitive impairment, ADHD, autism, and cognitive and language maturation in infants.

Over the past 50 years, a great deal of research has been directed at the importance of white matter. In 1965, science really began to study the brain’s structure as a means to diagnose and treat neurological disorders. As seen with the agenesis of the corpus callosum (ACC), the brain struggles to develop properly if the inter-hemispheric communication is hampered. Additionally, many processing disorders highlight the importance of sending the right signal to the right place; something as seemingly simple as misfiring neurons can lead to learning disabilities, behavior problems, emotional issues and a host of other cognitive impairments. The grey matter may represent the bulk of your memory and learned skills, but it is useless without the white matter carrying those signals around your brain and to your body.

And it is a lot of signals, some 120.4 quadrillion signals per second. Now, imagine a loss of white matter has cut off some of your functional brain networks due to physical damage. Let’s revisit our math from earlier. As a refresher, here is how we got 120.4 quadrillion:

86 billion neurons x 200 fires per second x 7,000 connections per fire = …

A whopping 120,400,000,000,000,000 or 120.4 quadrillion calculations per second.

Now, say that you lose access to 20% of those neurons…

69 billion neurons (20% reduction) x 200 fires per second x 7,000 connections = …

96,600,000,000,000,000 calculations per second.

Suddenly, you have lost a lot of processing speed per second. So, how will that affect you in daily life (i.e. how many calculations per day have you lost)?

24 hours x 60 minutes/hr x 60 seconds/min = 86,400 seconds/day

120.4 quadrillion x 86,400 = 10,402,560 quadrillion calculations per day


96.6 quadrillion x 86,400 = 8,346,240 quadrillion calculations per day

That is the equivalent to losing 4.8 hours a day. Obviously, you don’t really lose those hours if you have brain damage, but it highlights how much harder the brain has to work to accomplish a day’s worth of tasks. While most people spend that much time tuning out to television and video games, it isn’t as if your brain is shut off; you can still think about something. Just taking away the brain’s ability to talk to itself literally robs you of the ability to think efficiently and effectively. It is easier to understand the cognitive impairments associated with white matter maladies when you see the shear loss of the brain’s potential. It is no wonder that the symptoms seem to affect every aspect of daily life. As Dr. Lonnie Nelson said during his presentation on the DVBIC study results:

White matter connections are long bundles of axons that connect different cortical (gray matter) operators, where basic calculations take place. The loss of white matter connections (which happens in blast injury) is what keeps areas of the cortex from being able to share information across domains. This results in inefficient processing, slowed speed of processing, and problems with sensory integration. Repair of these white matter connections is likely what accounts for the improvements in cognition that we observed after IM.

Although Dr. Nelson was speaking about blast-related brain injuries in veterans, the same principle applies to all brain injuries. Whether you are young or old, severe and traumatic blows to the head affect the whole brain, both grey and white matter. Without the white matter, however, the brain simply can’t speak to itself, which can leave people feeling trapped in their own body. So, how can medical professionals help people protect their valuable white matter?

Sadly, it seems the more questions science answers, the more that arise. White matter does not develop at the same pace as other brain tissue; some white matter is still developing beyond 20 years of age and white matter begins to disappear earlier in old age than other brain tissue. Since the loss of white matter essentially means lost connections, this may help to explain why the cognitive impairments associated with old age are often associated with slowed processing and forgetfulness. It may also help researchers understand why some symptoms of SPD and autism may become easier to deal with later in life, and not just after sufferers have become accustomed. Lastly, just knowing that white matter is still developing into early maturity is all the more reason to continue education and brain training for years after schooling typically ends.

Just knowing that new connections can develop in our white matter tracts is an exciting prospect. No longer must individuals live with debilitating neuromuscular conditions and cognitive impairments; now, with IM training, people of all ages can directly address the underlying problem. The following explanation from Dr. Kevin McGrew is taken from the “Three-level Hypothesized Explanation of the IM effect (McGrew, 2012):”

Interactive Metronome® (IM) is believed to improve the resolution and efficiency of an individual’s internal brain clock(s) and temporal processing. In turn, it is hypothesized that this results in more efficient brain connectivity, communication, and synchronization via increased integrity of the brains white matter tract communication system, producing more efficient communication between critical brain networks. In particular, research and theory suggests that IM training increases the efficacy of the parietal-frontal brain network, the brain network most associated with general intellectual functioning, working memory, controlled attention and executive functions.

Restoring the critical timing and rhythm of brain communication is essential to restoring function. Truly efficient neuron firing can only come when each message sent is received, meaning that the brain’s functional networks must be healthy and in sync. The domain-general mechanism of timing is a “jack of all trades” mechanism that manifests itself in sleep cycles, speech patterns, the ability to attend over time and overall efficacy of brain communication. This timing in the brain, or temporal processing, has been shown to be deficient in several common conditions, including everything from ADHD to severe autism spectrum disorder.

When everything is working at the optimum level, the brain’s cognitive processes are free to work on memory, processing and coordinating action, all while still maintaining focus! This can help children concentrate in crowded classrooms or adults maintain sanity in a room full of children. IM training addresses sustained attention, impulse control, timing, sensory processing and sequencing by guiding users to repeatedly respond to a cue across varying lengths of time. Research shows that combining whole body movements with cognitive tasks leads to overall better outcomes. With IM training, there is no need for medication that only addresses the symptoms, not the source of the problem.

In Improvement in interval timing tracking and effects on reading achievement, Taub et al (2007) theorized that Interactive Metronome® primarily addresses thinking speed and working memory, thereby improving our ability to focus and learn. In the study, they demonstrated that Interactive Metronome® (IM) training has a significant positive effect on reading achievement (affecting 4 of 5 critical pre-reading skills) in elementary school students. They proposed that IM training was primarily improving “processing speed,” which in turn improved the students’ ability to allocate resources for attending and holding information in working memory…all essential for fluent reading. Taub et al propose that the wide array of positive treatment results seen following Interactive Metronome® training can be attributed to its impact on timing in the brain and two critically important skills, working memory and controlled attention.

We have said it before, although your brain is 40% grey matter and 60% white matter, it all matters. You can work out and eat healthy to maintain the brain’s physical structure, but let IM training take your brain to the next level. IM training might even make you a better dancer! Don’t believe us, be sure to check back for the next part in our series where we’ll discuss rhythm and how it affects coordination and brain communication.

But it is so much more than dancing and clapping! Now, people ages 1 to 101 can restore function to the brain’s temporal processing network, not simply rehabilitate and adapt to deficits. It doesn’t matter if it is an 8 year-old boy that is falling behind in school or a hard working 45 year-old mother of two who was injured in a car accident. Don’t wait for something to happen. It is about TIME you supercharge your brain!

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