Contribution of transcranial magnetic stimulation to the understanding of cortical mechanisms involved in motor control.
Transcranial magnetic stimulation (TMS) was initially used to evaluate the integrity of the corticospinal tract in humans non-invasively. Since these early studies, the development of paired-pulse and repetitive TMS protocols allowed investigators to explore inhibitory and excitatory interactions of various motor and non-motor cortical regions within and across cerebral hemispheres. These applications have provided insight into the intracortical physiological processes underlying the functional role of different brain regions in various cognitive processes, motor control in health and disease and neuroplastic changes during recovery of function after brain lesions. Used in combination with neuroimaging tools, TMS provides valuable information on functional connectivity between different brain regions, and on the relationship between physiological processes and the anatomical configuration of specific brain areas and connected pathways. More recently, there has been increasing interest in the extent to which these physiological processes are modulated depending on the behavioural setting. The purpose of this paper is (a) to present an up-to-date review of the available electrophysiological data and the impact on our understanding of human motor behaviour and (b) to discuss some of the gaps in our present knowledge as well as future directions of research in a format accessible to new students and/or investigators. Finally, areas of uncertainty and limitations in the interpretation of TMS studies are discussed in some detail.
Reis
Janine
J
Human Cortical Physiology Section, National Institute of Health, National Institute of Neurological Disorders and Stroke, 10 Center Drive, Bldg 10, Rm 5 N226, Bethesda, MD 20892, USA.
Swayne
Orlando B
OB
Vandermeeren
Yves
Y
Camus
Mickael
M
Dimyan
Michael A
MA
Harris-Love
Michelle
M
Perez
Monica A
MA
Ragert
Patrick
P
Rothwell
John C
JC
Cohen
Leonardo G
LG
D019054:Evoked Potentials, Motor / Q000502:physiology; D006801:Humans; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D050781:Transcranial Magnetic Stimulation