You made many major scientific contributions in multiple sclerosis field. One of them is discovery of importance of neuronal and axonal loss in multiple sclerosis. Dr. Anton Titov, MD. This makes multiple sclerosis a neurodegenerative disease. Multiple sclerosis is not "just" an autoimmune disease. There is a loss of neurons and axons after multiple sclerosis relapses. Dr. Anton Titov, MD. This implies an effective mechanism for recovery of brain function in patients with relapsing-remitting multiple sclerosis. Dr. Paul M. Matthews, MD. We have already spoke a little bit about relapsing-remitting multiple sclerosis. It is known that patients with relapsing-remitting multiple sclerosis retain functional abilities very well and for a long time. We know that axons and neurons are lost after a relapse in multiple sclerosis. Dr. Anton Titov, MD. How does recovery of neurological functions occur after relapses in multiple sclerosis? Functional recovery after relapses can occur by a variety of mechanisms. Dr. Paul M. Matthews, MD. When there are still axonal substrates left, neuron repair is possible. Remyelination of axons can occur. That can enable neurons to recover any impaired functions. Neurons can maintain their function over the longer term. However, many axons are irreversibly damaged. Many neurons are irreversibly injured. Nerve cells die in multiple sclerosis. Dr. Paul M. Matthews, MD. We already discussed this previously. In these cases, the brain uses its extraordinary redundancy for recovery of neurological function. Each nerve cell has 10,000 or so synaptic connections. Each synaptic connection in turn interacts with similarly large numbers of nerve cells. What this enables is a rich network of nerve cells in the brain. Neurons can take over for each other within a given functional system to a significant extent. This happens even when damage occurs. This functional compensation in multiple sclerosis is a spontaneous process. But it can be enhanced by experience and continued learning. Dr. Anton Titov, MD. This is the role of neurorehabilitation in multiple sclerosis. It may be very difficult to perform walking or gripping an object in the immediate aftermath of a relapse. Repetitive practice of a task, such as grip or gait, becomes progressively improved. Dr. Paul M. Matthews, MD. The brain learns new ways of adapting to the loss of nerve cells. This can occur by expansion of the region of the brain that is responsible for control of the movement or perception of the sensation. In some cases, there is evidence for functionally related areas to take on additional duties. This happens in the visual cortex. This compensation of neurological function can be enhanced by a higher-order control areas of the brain. There are “control areas” in the prefrontal cortex. They are responsible for the allocation of resources for given tasks between hierarchically lower-order areas of the brain. These areas of the brain are responsible for action or perception. The recovery at some point is imperfect. This begins to occur when the area of brain outside of the new lesion is itself showing a greater damage. This greater damage is associated with lower resilience. Dr. Paul M. Matthews, MD. More damage to the brain cells in multiple sclerosis happens. It leads to lower capacity for this reprogramming to occur. It also depends very much on experience. So patient may fails to use an impaired limb. Then the functions of that limb may not recover to the extent that they would otherwise. Or function of the arm or leg may not recover at all. Dr. Anton Titov, MD. This is the concept of "learned disuse". All these principles have come to multiple sclerosis from clinical trials in patients with strokes. Some patients had are single isolated lesions that can be studied carefully in the absence of other damage to the brain. Dr. Paul M. Matthews, MD. But I think it is a brain function recovery principle that now is extending across a whole range of neurodegenerative diseases. This is now used in diseases as diverse as Alzheimer's disease and Parkinson's disease. Dr. Anton Titov, MD. We have to understand the ability of patients to retain relatively normal levels of behavior for extended periods of time. Truly, multiple sclerosis is a testament to the adaptive abilities and plasticity of the brain. It is a testament to immunological and neurodegenerative damage. Dr. Paul M. Matthews, MD. I think so. One of the exciting areas for research in multiple sclerosis in the future is this. We must understand the molecular determinants of this adaptive recovery of brain function. How brains might be wired in different ways prior to the development of multiple sclerosis. This makes it likely for this recovery of brain function to occur. Dr. Anton Titov, MD. With this information, we will be able to make better prognosis for patients with multiple sclerosis in the future.