title: Cerebellar sensory processing alterations impact motor cortical plasticity in Parkinson's disease: clues from dyskinetic patients.
abstract: The plasticity of primary motor cortex (M1) in patients with Parkinson's disease (PD) and levodopa-induced dyskinesias (LIDs) is severely impaired. We recently reported in young healthy subjects that inhibitory cerebellar stimulation enhanced the sensorimotor plasticity of M1 that was induced by paired associative stimulation (PAS). This study demonstrates that the deficient sensorimotor M1 plasticity in 16 patients with LIDs could be reinstated by a single session of real inhibitory cerebellar stimulation but not sham stimulation. This was evident only when a sensory component was involved in the induction of plasticity, indicating that cerebellar sensory processing function is involved in the resurgence of M1 plasticity. The benefit of inhibitory cerebellar stimulation on LIDs is known. To explore whether this benefit is linked to the restoration of sensorimotor plasticity of M1, we conducted an additional study looking at changes in LIDs and PAS-induced plasticity after 10 sessions of either bilateral, real inhibitory cerebellar stimulation or sham stimulation. Only real and not sham stimulation had an antidyskinetic effect and it was paralleled by a resurgence in the sensorimotor plasticity of M1. These results suggest that alterations in cerebellar sensory processing function, occurring secondary to abnormal basal ganglia signals reaching it, may be an important element contributing to the maladaptive sensorimotor plasticity of M1 and the emergence of abnormal involuntary movements.
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India asha@sctimst.ac.in.
authors.forename: Asha
authors.initials: A
authors.lastname: Kishore
authors.affiliation: Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris 75013, France CNRS, UMR 7225, Paris 75013, France INSERM, U975, Paris 75013, France ICM-Institut du Cerveau et de la Moëlle épinière, Paris 75013, France.
authors.forename: Traian
authors.initials: T
authors.lastname: Popa
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India.
authors.forename: Ammu
authors.initials: A
authors.lastname: Balachandran
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India.
authors.forename: Shyambabu
authors.initials: S
authors.lastname: Chandran
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India.
authors.forename: Salini
authors.initials: S
authors.lastname: Pradeep
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India.
authors.forename: Febina
authors.initials: F
authors.lastname: Backer
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala 695011, India.
authors.forename: Syam
authors.initials: S
authors.lastname: Krishnan
authors.affiliation: Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris 75013, France CNRS, UMR 7225, Paris 75013, France INSERM, U975, Paris 75013, France ICM-Institut du Cerveau et de la Moëlle épinière, Paris 75013, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Meunier
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects* / Q000627:therapeutic use; D002531:Cerebellum / Q000187:drug effects / Q000503:physiopathology*; D004409:Dyskinesia, Drug-Induced / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D004576:Electromyography; D019054:Evoked Potentials, Motor; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D007980:Levodopa / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology*; D012720:Severity of Illness Index; D050781:Transcranial Magnetic Stimulation / Q000379:methods
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Parkinson's disease; cerebellum; dyskinesias; l-DOPA; motor cortex plasticity