What happens in the brain?

The neurology behind MFD

 

Musician’s Focal Dystonia is classified as a neurological condition, and as such, is diagnosed and treated by neurologists. In spite of this fact, most musicians with MFD have very little information about the actual neural mechanisms of the condition. I think that knowing what is actually going on in our heads when suffering from MFD might bring not only understanding but maybe also compassion and kindness towards ourselves. Also, based on this knowledge, it is easier to understand how behavioural therapies work.

Therefore, in this short article, I’ll try to summarise the newest findings of brain research, neuroscience, and neuroplasticity, and discuss in plain words what is actually happening in our brain when we suffer from MFD.

 

The ongoing research 

Many researchers started to study the brain and its changes in people with MFD. When I say study, I mostly mean two main tools: magnetic resonance imaging (MRI) and magnetoencephalography (MEG). These work in very complicated ways, but for us, it is enough to know that they both use magnetic fields to understand the different brain tissues and the communication between nerve cells.

There are three main areas which show changes in people with MFD, the somatosensory cortex, the motor cortex, and the basal ganglia (keep reading, I’ll explain it all!).

 

The Somatosensory Cortex and the Motor Cortex

 

The Somatosensory Cortex and the Motor Cortex are areas in the Cerebral Cortex. This is the outermost layer of the human brain, much like the skin on an orange. Different parts of the Cerebral Cortex are responsible for different functions, such as memory, attention, language, interpreting the environment and so on.

The Somatosensory Cortex’s task is to process sensations and external stimuli, such as touch, visual and auditory signals coming from the environment. Meaning that this is the part of the brain which is going to deal with the touch of the string on your finger or the mouthpiece on your lips, but also the sound you’re hearing and the music you’re looking at. The Somatosensory Cortex is located roughly in the top of your skull.

The Motor Cortex is the neighbor of the Somatosensory Cortex, and as its name suggests, its function is the planning and executing voluntary movement. All the movements performed consciously run through the Motor Cortex. Which means that when you’re consciously moving your fingers, embouchure, feet etc., you’re doing it with the help of your Motor Cortex.

 

Problems in the homunculus

 

The Somatosensory and Motor Cortex is organised in such a way, that each body part is represented in it, but not equally. We need more sensitivity and motor control in our fingertips than in the middle of our backs, therefore the representation of the fingers is going to occupy a larger chunk in the Somatosensory and Motor Cortex than the back. Each body part is represented proportionately. There is a funny image, the so-called ‘homunculus’, which shows how these representations relate to each other.

 

 

 

And here comes the interesting part. The areas representing parts of our body can change and grow. This is a natural process, and musicians tend to have more developed representations of their hands or lips (in wind players) (Altenmüller & Jabusch, 2009) because of the intense practice. What happens in the case of MFD is these areas both in the Somatosensory and in the Motor Cortex seem to develop too far and start to overlap (Altenmüller & Jabusch, 2006).  As an example, the little area in the cortex which is responsible for moving the digits of your index finger, start to overlap with the area which is controlling the middle finger.

This means that the signals, running from the brain to the muscles, get tangled and unclear. It must be like listening to two radio channels at the same time. Some signals from this overlapping area arrive in more than one digit, muscle group, body part. This entanglement is much easier to see in finger and hand dystonias since the researchers can compare the images of the dystonic and non-dystonic hands.

 

Muscle-pairs

 

There are additional problems as well with a mechanism in the brain called ‘reciprocal inhibition’. Let me unpack this expression. We usually have two sets of opposing muscles in each side of our joints (known as agonist and antagonist or flexors and extensors). These pairs are everywhere, but perhaps the most common example is the triceps and the biceps: if you straighten your arm, the triceps is working, but if you pull something towards you, you’re working with your biceps. Naturally, if one is working, the other one is at rest. Reciprocal inhibition is the process which blocks one set of these muscle pairs, so the other can move effortlessly and freely.

Researchers found that these pairs of muscles get activated simultaneously in the dystonic body part (Hallett, 1998; Charness & Schlaug, 2004; Berque, Gray, Harkness &McFadyen, 2013.) The pairs attempt to work at the same time, resulting in tension and crippled movement control. (Byl, Merzenich, Jenkins et al., 1996; Candia, Wienbruch, Elbert et al., 2003). When it comes to the brain, this activation can be traced back to the somatosensory cortex: the brain simply does not signal the opposing muscle to deactivate.

Also, over-activation has been found in the Motor Cortex: the neurons which are responsible for sending information about the movement to your muscles get too excited and start to fire more than needed (Hallett, 1998; Berque et al, 2013).

 

Basal ganglia

 

The other culprit is the basal ganglia, which sits more or less in the middle of the brain, therefore it is often called the basal nucleus (see the first picture). This area also plays part in the voluntary movement, but also in cognition and emotion. Researchers found similar changes in this area as well: the inhibition of unnecessary movements do not function properly, and the motor output is increased (Berque et al., 2013).

 

So, what can we do about it?

 

First of all, I feel that it is important to understand to a certain extent what is going on in our brains when experiencing MFD symptoms. We don’t have to become neuroscientists to grasp a couple of ideas. Knowledge can help to understand the condition less and less as an unknown force which mysteriously ruined our lives, and more like any other illness with a logical explanation and possible solutions.

 

Even more importantly, some researchers decided to test if they could ‘reset’ the brain relying on neuroplasticity. This is what we know as behavioural therapy, coaching or retraining. There are many different kinds out there, and in some cases, the success is demonstrated by actual changes in the brain scans – in other words, researchers were able to detect, and measure the changes which occurred in the brain as a result of the behavioural therapy! I personally find this extremely exciting.

It’s been shown that after only 8 weeks of retraining, the re-organisation of the brain is already underway (Candia, Wienbruch, Elbert et al., 2003). We might not feel it, and some researchers give an estimated 8 months of active retraining to have meaningful changes (Berque, 2013), but we know it is happening.

Summary 

All these changes I described in this article are reversible. It is actually proven by studies, that the right type of retraining exercises can physically change the structure of the brain. We can teach our brain to give the right signals again, we can teach the brain to go back to the normal functioning. It is a long and hard process, but we can prove with brain scans that it is actually happening.

There has only been anecdotal evidence until a couple of years ago, but now we can confidently say that recovery is possible through re-learning, re-training, and behavioural therapies.

 

References:

 

Altenmüller, E. & Jabusch, H.Ch. (2006). Focal dystonia in musicians: From phenomenology to therapy. Advances in Cognitive Psychology, 2(2-3), 207-220.

Altenmüller, E. & Jabusch, H.Ch. (2009). Focal hand dystonia in musicians: phenomenology, etiology, and psychological trigger factors. Journal of Hand Therapy, 22(2), 145-154.

Berque, P., Gray, H. Harkness, C. &McFadyen, A. (2013). A combination of constraint-induced therapy and motor control retraining in the treatment of focal hand dystonia in musicians. Medical Problems of Performing Artists, 25(4), 149-154.

Candia, V., Wienbruch, C., Elbert, T., Rockstroh, B., & Ray, W. (2003). Effective behavioral treatment of focal hand dystonia in musicians alters somatosensory cortical organization. Proceedings of the National Academy of Sciences of the United States of America, 100(13), 7942–7946.

Charness, M. E., & Schlaug, G. (2004). Brain mapping in musicians with focal task-specific dystonia. Advances in Neurology, 94, 231–238. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/14509678

Hallett, M. (1998). The Neurophysiology of Dystonia. Archives of Neurology, 55(5), 601. https://doi.org/10.1001/archneur.55.5.601

 

 

 

 

 

 

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