Two Wrongs Make a Right – Abnormal Brain Circuitry May Stop Abnormal Movement

A solution to an abnormal neurological movement problem can perhaps be abnormal as well. The irregular wiring of the brain may actually eliminate dystonia — repetitive movements and atypical postures. According to the Journal of Neuroscience, changes in brain pathways may actually counteract the genetic mutations for the movement disorder. This idea can explain why a few individuals with the inherited mutation are able to live normal lives.

Researchers at the Feinstein Institute identified two specific brain pathways that influence the severity of dystonia symptoms. All individuals who carry the mutations and symptoms for dystonia have an abnormal pathway between the cerebellum and the thalamus, but a normal second pathway between the thalamus and the cortex. Indeed, it is the people who carry the mutations but have no symptoms of dystonia that have this abnormal second pathway. Scientists believe that the different brain pathways are formed at an early stage of brain development. This phenomenon gives a whole new meaning to the logical fallacy of “two wrongs make a right.” When one wrong is committed (genetic mutation), another wrong will cancel it out (the abnormal thalamus and cortex connection).

The finding can bring many implications. For one thing, the study could lead to new treatments and prevention options for patients with dystonia. Additionally, it could provide better understanding to other neurological illnesses, especially those involving movement, such as the more popular, Parkinson’s disease. Conceivably, the abnormal brain wiring may be similar to the electrical stimulation used in treating movement disorders. The preferred surgical treatment for these disorders is the chronic electrical stimulation of the brain, known as deep brain stimulation (DBS). It has been shown that DBS improves motor symptoms, although we do not exactly know how stimulation works in a physiological level. Do abnormal brain circuits between the thalamus and cortex act like the DBS therapy? Does the irregular wiring of the brain, due to developmental problems, improve dystonia, in the same way as our known therapies?

The developmental changes in brain wiring could be the same as foreign electrical stimulation, in that they both modify transmission in movement through an unknown mechanism.

Reference

Johnson MD, Miocinovic S, McIntyre CC, & Vitek JL (2008). Mechanisms and targets of deep brain stimulation in movement disorders. Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 5 (2), 294-308 PMID: 18394571