[The pathophysiological basis of dystonia]

We review the mechanisms that may involved in the pathophysiology of dystonia.

The role of basal ganglia, spinal and brainstem interneurons, and primary motor cortex in dystonia will be discussed. Abnormalities in the discharge pattern of internal pallidum or thalamus, secondary to basal ganglia disorders might be the cause of disbalance between excitatory and inhibitory mechanisms in motor cortex. Other factors such as excessive repetition of a movement or abnormal sensory afferent discharges may be participating in cortical reorganization.

Overlapping of the cortical representation of dystonic muscles due to enlargement of cortical maps could explain overflow and co-contraction phenomena. The study of the exact role of these factors in each type of dystonia is a challenge for the future that opens the door for new therapeutic approaches.