Tags

Type your tag names separated by a space and hit enter

Abnormal excitability of premotor-motor connections in de novo Parkinson's disease.
Brain. 2004 Dec; 127(Pt 12):2732-46.B

Abstract

The dorsal premotor cortex (PMd) is abnormally active in patients with idiopathic Parkinson's disease. This has been interpreted as a functional correlate of adaptive plasticity within the motor system to compensate for deficient activation of striato-mesial-frontal projections in these patients. Whether abnormal PMd activity influences excitability in the primary motor cortex (M1) in untreated Parkinson's disease patients and how this premotor-motor interaction might be altered by l-dopa is unclear. To this end, we studied the effects of 1 Hz premotor repetitive transcranial magnetic stimulation (rTMS) on M1 excitability in 10 previously untreated non-tremulous Parkinson's disease patients before (day 1) and after (day 8) their first ever l-dopa treatment and compared the results with those of a group of nine age- and sex-matched healthy controls. In each rTMS session, 1200 pulses of 1 Hz rTMS were applied at an intensity of 80% active motor threshold (AMT) to the PMd contralateral to the clinically more affected side in Parkinson's disease patients and to the left PMd in healthy controls. Intracortical paired pulse excitability of ipsilateral M1 was probed using a TMS paired pulse paradigm where subthreshold conditioning pulses (80% of AMT) were given 2-15 ms prior to a suprathreshold test pulse. In Parkinson's disease patients, abnormal baseline intracortical excitability at an interstimulus interval (ISI) of 5 ms was normalized by premotor rTMS. In contrast, rTMS led to an increased excitability at an ISI of 5 ms in healthy controls. Premotor rTMS effects lasted longer (for at least a week) in patients. These results show that the modifiability of premotor-motor connections is abnormal in untreated Parkinson's disease. A single dose of l-dopa reversed, i.e. normalized, the direction of excitability changes in M1 following premotor rTMS in Parkinson's disease patients, suggesting that dopamine depletion directly or indirectly influences premotor-motor interactions in Parkinson's disease. The rTMS conditioning approach described here provides a promising tool to delineate further the excitability changes in frontal motor areas in response to progressive degeneration of nigrostriatal dopaminergic neurons and also to chronic l-dopa treatment in Parkinson's disease.

Authors+Show Affiliations

Department of Neurology, University of Hamburg, Hamburg, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15509619

Citation

Buhmann, C, et al. "Abnormal Excitability of Premotor-motor Connections in De Novo Parkinson's Disease." Brain : a Journal of Neurology, vol. 127, no. Pt 12, 2004, pp. 2732-46.
Buhmann C, Gorsler A, Bäumer T, et al. Abnormal excitability of premotor-motor connections in de novo Parkinson's disease. Brain. 2004;127(Pt 12):2732-46.
Buhmann, C., Gorsler, A., Bäumer, T., Hidding, U., Demiralay, C., Hinkelmann, K., Weiller, C., Siebner, H. R., & Münchau, A. (2004). Abnormal excitability of premotor-motor connections in de novo Parkinson's disease. Brain : a Journal of Neurology, 127(Pt 12), 2732-46.
Buhmann C, et al. Abnormal Excitability of Premotor-motor Connections in De Novo Parkinson's Disease. Brain. 2004;127(Pt 12):2732-46. PubMed PMID: 15509619.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Abnormal excitability of premotor-motor connections in de novo Parkinson's disease. AU - Buhmann,C, AU - Gorsler,A, AU - Bäumer,T, AU - Hidding,U, AU - Demiralay,C, AU - Hinkelmann,K, AU - Weiller,C, AU - Siebner,H R, AU - Münchau,A, Y1 - 2004/10/27/ PY - 2004/10/29/pubmed PY - 2005/1/20/medline PY - 2004/10/29/entrez SP - 2732 EP - 46 JF - Brain : a journal of neurology JO - Brain VL - 127 IS - Pt 12 N2 - The dorsal premotor cortex (PMd) is abnormally active in patients with idiopathic Parkinson's disease. This has been interpreted as a functional correlate of adaptive plasticity within the motor system to compensate for deficient activation of striato-mesial-frontal projections in these patients. Whether abnormal PMd activity influences excitability in the primary motor cortex (M1) in untreated Parkinson's disease patients and how this premotor-motor interaction might be altered by l-dopa is unclear. To this end, we studied the effects of 1 Hz premotor repetitive transcranial magnetic stimulation (rTMS) on M1 excitability in 10 previously untreated non-tremulous Parkinson's disease patients before (day 1) and after (day 8) their first ever l-dopa treatment and compared the results with those of a group of nine age- and sex-matched healthy controls. In each rTMS session, 1200 pulses of 1 Hz rTMS were applied at an intensity of 80% active motor threshold (AMT) to the PMd contralateral to the clinically more affected side in Parkinson's disease patients and to the left PMd in healthy controls. Intracortical paired pulse excitability of ipsilateral M1 was probed using a TMS paired pulse paradigm where subthreshold conditioning pulses (80% of AMT) were given 2-15 ms prior to a suprathreshold test pulse. In Parkinson's disease patients, abnormal baseline intracortical excitability at an interstimulus interval (ISI) of 5 ms was normalized by premotor rTMS. In contrast, rTMS led to an increased excitability at an ISI of 5 ms in healthy controls. Premotor rTMS effects lasted longer (for at least a week) in patients. These results show that the modifiability of premotor-motor connections is abnormal in untreated Parkinson's disease. A single dose of l-dopa reversed, i.e. normalized, the direction of excitability changes in M1 following premotor rTMS in Parkinson's disease patients, suggesting that dopamine depletion directly or indirectly influences premotor-motor interactions in Parkinson's disease. The rTMS conditioning approach described here provides a promising tool to delineate further the excitability changes in frontal motor areas in response to progressive degeneration of nigrostriatal dopaminergic neurons and also to chronic l-dopa treatment in Parkinson's disease. SN - 1460-2156 UR - https://www.unboundmedicine.com/medline/citation/15509619/Abnormal_excitability_of_premotor_motor_connections_in_de_novo_Parkinson's_disease_ L2 - https://academic.oup.com/brain/article-lookup/doi/10.1093/brain/awh321 DB - PRIME DP - Unbound Medicine ER -