title: Cortical motor overactivation in parkinsonian patients with L-dopa-induced peak-dose dyskinesia.
abstract: We have studied the regional cerebral blood flow (rCBF) changes induced by the execution of a finger-to-thumb opposition motor task in the supplementary and primary motor cortex of two groups of parkinsonian patients on L-dopa medication, the first one without L-dopa induced dyskinesia (n = 23) and the other with moderate peak-dose dyskinesia (n = 15), and of a group of 14 normal subjects. Single photon emission tomography with i.v. 133Xe was used to measure the rCBF changes. The dyskinetic parkinsonian patients exhibited a pattern of response which was markedly different from those of the normal subjects and non-dyskinetic parkinsonian patients, with a significant overactivation in the supplementary motor area and the ipsi- and contralateral primary motor areas. These results are compatible with the hypothesis that an hyperkinetic abnormal involuntary movement, like L-dopa-induced peak dose dyskinesia, is due to a disinhibition of the primary and associated motor cortex secondary to an excessive outflow of the pallidothalamocortical motor loop.
authors.affiliation: INSERM U455, University Hospital of Toulouse, France.
authors.forename: O
authors.initials: O
authors.lastname: Rascol
authors.forename: U
authors.initials: U
authors.lastname: Sabatini
authors.forename: C
authors.initials: C
authors.lastname: Brefel
authors.forename: N
authors.initials: N
authors.lastname: Fabre
authors.forename: S
authors.initials: S
authors.lastname: Rai
authors.forename: J M
authors.initials: JM
authors.lastname: Senard
authors.forename: P
authors.initials: P
authors.lastname: Celsis
authors.forename: G
authors.initials: G
authors.lastname: Viallard
authors.forename: J L
authors.initials: JL
authors.lastname: Montastruc
authors.forename: F
authors.initials: F
authors.lastname: Chollet
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002560:Cerebrovascular Circulation / Q000502:physiology; D004409:Dyskinesia, Drug-Induced / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007980:Levodopa / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015999:Multivariate Analysis; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D012016:Reference Values; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D007980:Levodopa