Georgios Naros1, Florian Grimm1, Daniel Weiss2, Alireza Gharabaghi1. 1. Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Tuebingen, Germany. 2. Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, and German Centre of Neurodegenerative Diseases (DZNE), Eberhard Karls University Tuebingen, Tuebingen, Germany.
Abstract
BACKGROUND: Both the cerebello-thalamo-cortical circuit and the basal ganglia/cortical motor loop have been postulated to be generators of tremor in PD. The recent suggestion that the basal ganglia trigger tremor episodes and the cerebello-thalamo-cortical circuitry modulates tremor amplitude combines both competing hypotheses. However, the role of the STN in tremor generation and the impact of proprioceptive feedback on tremor suppression during voluntary movements have not been considered in this model yet. OBJECTIVES: The objective of this study was to evaluate the role of the STN and proprioceptive feedback in PD tremor generation during movement execution. METHODS: Local-field potentials of the STN as well as electromyographical and electroencephalographical rhythms were recorded in tremor-dominant and nontremor PD patients while performing voluntary movements of the contralateral hand during DBS surgery. Effective connectivity between these electrophysiological signals were analyzed and compared to electromyographical tremor activity. RESULTS: There was an intensified information flow between the STN and the muscle in the tremor frequencies (5-8 Hz) for tremor-dominant, in comparison to nontremor, patients. In both subtypes, active movement was associated with an increase of afferent interaction between the muscle and the cortex in the β- and γ-frequencies. The γ-frequency (30-40 Hz) of this communication between muscle and cortex correlated inversely with electromyographical tremor activity. CONCLUSIONS: Our results indicate an involvement of the STN in propagation of tremor-related activity to the muscle. Furthermore, we provide evidence that increased proprioceptive information flow during voluntary movement interferes with central tremor generation.
BACKGROUND: Both the cerebello-thalamo-cortical circuit and the basal ganglia/cortical motor loop have been postulated to be generators of tremor in PD. The recent suggestion that the basal ganglia trigger tremor episodes and the cerebello-thalamo-cortical circuitry modulates tremor amplitude combines both competing hypotheses. However, the role of the STN in tremor generation and the impact of proprioceptive feedback on tremor suppression during voluntary movements have not been considered in this model yet. OBJECTIVES: The objective of this study was to evaluate the role of the STN and proprioceptive feedback in PD tremor generation during movement execution. METHODS: Local-field potentials of the STN as well as electromyographical and electroencephalographical rhythms were recorded in tremor-dominant and nontremor PDpatients while performing voluntary movements of the contralateral hand during DBS surgery. Effective connectivity between these electrophysiological signals were analyzed and compared to electromyographical tremor activity. RESULTS: There was an intensified information flow between the STN and the muscle in the tremor frequencies (5-8 Hz) for tremor-dominant, in comparison to nontremor, patients. In both subtypes, active movement was associated with an increase of afferent interaction between the muscle and the cortex in the β- and γ-frequencies. The γ-frequency (30-40 Hz) of this communication between muscle and cortex correlated inversely with electromyographical tremor activity. CONCLUSIONS: Our results indicate an involvement of the STN in propagation of tremor-related activity to the muscle. Furthermore, we provide evidence that increased proprioceptive information flow during voluntary movement interferes with central tremor generation.
Authors: Luka Milosevic; Suneil K Kalia; Mojgan Hodaie; Andres M Lozano; Milos R Popovic; William D Hutchison Journal: Brain Date: 2018-07-01 Impact factor: 13.501
Authors: Kristina J Pfeifer; Justus A Kromer; Alexander J Cook; Traci Hornbeck; Erika A Lim; Bruce J P Mortimer; Adam S Fogarty; Summer S Han; Rohit Dhall; Casey H Halpern; Peter A Tass Journal: Front Physiol Date: 2021-04-06 Impact factor: 4.566