title: Intrinsic signature of essential tremor in the cerebello-frontal network.
abstract: Essential tremor is a movement disorder characterized by tremor during voluntary movements, mainly affecting the upper limbs. The cerebellum and its connections to the cortex are known to be involved in essential tremor, but no task-free intrinsic signatures of tremor related to structural cerebellar defects have so far been found in the cortical motor network. Here we used voxel-based morphometry, tractography and resting-state functional MRI at 3 T to compare structural and functional features in 19 patients with essential tremor and homogeneous symptoms in the upper limbs, and 19 age- and gender-matched healthy volunteers. Both structural and functional abnormalities were found in the patients' cerebellum and supplementary motor area. Relative to the healthy controls, the essential tremor patients' cerebellum exhibited less grey matter in lobule VIII and less effective connectivity between each cerebellar cortex and the ipsilateral dentate nucleus. The patient's supplementary motor area exhibited (i) more grey matter; (ii) a lower amplitude of low-frequency fluctuation of the blood oxygenation level-dependent signal; (iii) less effective connectivity between each supplementary motor area and the ipsilateral primary motor hand area, and (iv) a higher probability of connection between supplementary motor area fibres and the spinal cord. Structural and functional changes in the supplementary motor area, but not in the cerebellum, correlated with clinical severity. In addition, changes in the cerebellum and supplementary motor area were interrelated, as shown by a correlation between the lower amplitude of low-frequency fluctuation in the supplementary motor area and grey matter loss in the cerebellum. The structural and functional changes observed in the supplementary motor area might thus be a direct consequence of cerebellar defects: the supplementary motor area would attempt to reduce tremor in the motor output by reducing its communication with M1 hand areas and by directly modulating motor output via its corticospinal projections.See Raethjen and Muthuraman (doi:10.1093/brain/awv238) for a scientific commentary on this article.
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France cecile.gallea.icm@gmail.com.
authors.forename: Cécile
authors.initials: C
authors.lastname: Gallea
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Traian
authors.initials: T
authors.lastname: Popa
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: García-Lorenzo
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Valabregue
authors.affiliation: 5 ESPCI, Paris Sciences, Paris, France.
authors.forename: André-Pierre
authors.initials: AP
authors.lastname: Legrand
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Lea
authors.initials: L
authors.lastname: Marais
authors.affiliation: 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Degos
authors.affiliation: 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Hubsch
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Sara
authors.initials: S
authors.lastname: Fernández-Vidal
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Bardinet
authors.affiliation: 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Roze
authors.affiliation: 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 7 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neuroradiologie, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.affiliation: 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Vidailhet
authors.affiliation: 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Meunier
mesh_terms: D000328:Adult; D000368:Aged; D002531:Cerebellum / Q000098:blood supply / Q000473:pathology*; D020329:Essential Tremor / Q000473:pathology*; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009434:Neural Pathways / Q000098:blood supply / Q000473:pathology*; D010100:Oxygen / Q000097:blood; D012146:Rest; D012720:Severity of Illness Index
chemical_list: D010100:Oxygen
keywords: cerebellar function; frontal lobe; motor cortex; movement disorder: imaging; tremor