Mapping the electrophysiological structure of dystonic Globus Pallidus pars interna through intraoperative microelectrode recordings

ObjectiveThe Globus Pallidus pars interna (GPi) is one of the main targets for Deep Brain Stimulation (DBS) therapies for dystonia and other movement disorders. Still, a complete picture of the spiking dynamics of the nucleus is far from being achieved. Microelectrode recordings (MER) provide a unique brain window opportunity to shed light on GPi organization, which might support intraoperative DBS target localization, as previously done for the Subthalamic nucleus (STN). ApproachHere we propose a novel procedure to analyze explorative MERs from DBS implants in dystonic patients. The procedure identifies the neural activity markers discriminating neurons in the GPi from those in the neighbouring structures, as well as the markers discriminating neurons located in different regions within the GPi. Main resultsThe identification of the borders of the GPi based on neural markers was a difficult task, due to internal inhomogeneities in GPi firing dynamics. However, the procedure was able to exploit these inhomogeneities to characterize the internal electrophysiological structure of the GPi. In particular, we found a reliable dorsolateral gradient in firing activity and regularity. SignificanceOverall, we characterized the spatial distribution of neural activity markers in the dystonic GPi, paving the way for the use of these markers for DBS target localization. The procedure we developed to achieve this result could be easily extended to MER performed for other disorders and in other areas.