1Institute of Neurology, University College London, London, United Kingdom
2F.C. Donders Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Nijmegen, The Netherlands
Insight into how brain structures interact is critical for understanding the principles of brain function and may lead to better diagnosis and therapy. To study interactions between the cortex and deep brain structures (basal ganglia and the thalamus) we recorded, simultaneously, local field potentials (LFPs) from deep brain stimulation (DBS) electrodes and magnetoencephalographic (MEG) signals from the cerebral cortex (CTF 275 channel system) from Parkinson’s disease (PD) patients with bilateral DBS electrodes in the subthalamic nucleus (STN).
High-amplitude artefacts in the MEG, originating from slight movements of ferromagnetic parts of the electrode, pose a challenge to conventional analysis methods. However, we developed several methods capable of extracting physiologically meaningful patterns from the data.
We studied the patterns of coherence and directed coherence at rest between STN-LFP and MEG. Coherence patterns observed between 5 and 45 Hz varied in their topography between subjects. This variability can possibly be related to phenotypic differences among our patients.
We also examined movement-related spectral changes in STN and cortical sensorimotor areas. Our preliminary results show that task related changes at either cortical or STN level can influence the partner structure, offering an explanation of why neuromodulation at either level may potentially be effective.
This work was supported by: Marie Curie Intra European fellowship (contract MEIF-CT-2006-038858) and British Technion Society Coleman-Cohen Fellowship.