The role of synchronised low frequency activity in globus pallidus interna in dystonia.

Here we explore how abnormal spatio-temporal patterning of neuronal activity in the pallidum may contribute to dystonia. A critical feature of this abnormal patterning seems to be excessive synchronisation of neuronal activity over a 4-10 Hz frequency band. This is most readily apparent as fluctuation in the local field potential in this frequency band. Such activity correlates with the level of dystonic muscle activity and is concentrated in the internal segment of the globus pallidus, which is also the optimum surgical target in dystonia. It remains to be seen whether the abnormal low frequency activity is associated with dystonia through an abnormal processing of afferent information in the pallidum or to a more direct influence on the motor drive to dystonic muscles, which involves, at least in part, similar frequencies.