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Author Notes:

Correspondence: C.M. Buetefisch; Dept. of Neurology, Emory University School of Medicine, 1441 Clifton Road NE, Suite 236, Atlanta, GA 30322, USA. cathrin.m.buetefisch@emory.edu.

Authors' Contributions: Trisha M. Kesar carried out the data analysis and participated in the preparation of the manuscript.

Samir R. Belagaje and Paola Pergami carried out the experiments and participated in the preparation of the manuscript.

Marc W. Haut participated in the design of the experiments and preparation of the manuscript.

Gerald Hobbs carried out the statistical analysis of the data.

Cathrin M. Buetefisch designed the study, carried out the experiments and prepared the manuscript.

Acknowledgments: We thank our subjects for their participation in this study, Charles Korb, Courtney Howard, Robin Whitescarver, Becky Murray and Patricia Altemus for their help with the experiments, Dr. Stephan Goebel for the interpretation of the EKGs, and Dr. Sebastian Buetefisch for technical support.

Disclosures: None of the authors have potential conflicts of interest to be disclosed.

Subjects:

Research Funding:

Research reported in this publication was supported by the National Institute of Neurological Disorders And Stroke of the National Institutes of Health under Award Number R01NS060830, R56NS070879, R21HD067906, R01NS090677.

Dr. Kesar was supported by National Institutes of Health award number K01HD079584.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Neurosciences
  • Neurosciences & Neurology
  • Motor cortex
  • Monoaminergic drugs
  • Transcranial magnetic stimulation
  • Motor evoked potential
  • USE-DEPENDENT PLASTICITY
  • LONG-TERM POTENTIATION
  • TRANSCRANIAL MAGNETIC STIMULATION
  • PAIRED ASSOCIATIVE STIMULATION
  • AGE-RELATED-CHANGES
  • D-AMPHETAMINE
  • DOUBLE-BLIND
  • PREFRONTAL CORTEX
  • CHRONIC STROKE
  • RECOVERY

Effects of monoaminergic drugs on training -induced motor cortex plasticity in older adults

Tools:

Journal Title:

Brain Research

Volume:

Volume 1670

Publisher:

, Pages 106-117

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Primary motor cortex (M1) plasticity is involved in motor learning and stroke motor recovery, and enhanced by increasing monoaminergic transmission. Age impacts these processes but there is a paucity of systematic studies on the effects of monoaminergic drugs in older adults. Here, in ten older adults (age 61 + 4 years, 4 males), we determine the effects of a single oral dose of carbidopa/levodopa (DOPA), D-amphetamine (AMPH), methylphenidate (MEPH) and placebo (PLAC) on M1 excitability and motor training-induced M1 plasticity. M1 plasticity is defined as training related long lasting changes in M1 excitability and kinematics of the trained movement. At peak plasma level of the drugs, subjects trained wrist extension movements for 30 min. Outcome measures were motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation at increasing intensity (stimulus response curve, SRC) and peak acceleration of the trained wrist extension movements. Measures were obtained before and after completion of training. The curve parameters plateau (MEPmax), inflection point, and slope were extracted from SRC. At baseline drugs had a differential effect on curve parameters, while kinematics remained unchanged. Training alone (PLAC) increased MEPmax but did not improve kinematics. Drugs affected training-related changes of the curve parameters differently, but did not enhance them or kinematics when compared to PLAC. The results demonstrate that in the older adults, MEPH, DOPA, or AMPH have differential effects on baseline M1 excitability and training-related M1 plasticity but fail to enhance them above the naïve level.

Copyright information:

© 2017 Elsevier B.V.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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