Title
Enduring representational plasticity after somatosensory stimulation
Abstract
Somatosensory stimulation (SS), leading to increases in motor cortical excitability, influences motor performance in patients with brain lesions like stroke. The mechanisms by which SS modulates motor function are incompletely understood. Here, we used functional magnetic resonance imaging (fMRI, blood-oxygenation-level-dependent (BOLD), and perfusion imagings simultaneously acquired in a 3 T magnet) to assess the effects of SS on thumb-movement-related activation in three regions of interest (ROI) in the motor network: primary motor cortex (M1), primary somatosensory cortex (S1), and dorsal premotor cortex (PMd) in healthy volunteers. Scans were obtained in different sessions before and after 2-h electrical stimulation applied to the median nerve at the wrist (MNS), to the skin overlying the shoulder deltoid muscle (DMS), and in the absence of stimulation (NOSTIM) in a counterbalanced design. We found that baseline perfusion intensity was comparable within and across sessions. MNS but not DMS nor NOSTIM led to an increase in signal intensity and number of voxels activated by performance of median nerve-innervated thumb movements in M1, S1, and PMd for up to 60 min. Task-related fMRI activation changes were most prominent in M1 followed by S1 and to a lesser extent in PMd. MNS elicited a displacement of the center of gravity for the thumb movement representation towards the other finger representations within S1. These results indicate that MNS leads to an expansion of the thumb representation towards other finger representations within S1, a form of plasticity that may underlie the influence of SS on motor cortical function, possibly supporting beneficial effects on motor control.
Year
DOI
Venue
2005
10.1016/j.neuroimage.2005.05.055
NeuroImage
Keywords
Field
DocType
Somatosensory,Motor cortex,Premotor,fMRI,Reorganization,Nerve stimulation
Neuroscience,Thumb,Functional magnetic resonance imaging,Premotor cortex,Psychology,Motor control,Somatosensory system,Motor cortex,Primary motor cortex,Stimulation
Journal
Volume
Issue
ISSN
27
4
1053-8119
Citations 
PageRank 
References 
1
0.38
4
Authors
5
Name
Order
Citations
PageRank
carolyn w h wu150.94
Peter van Gelderen240335.74
Takashi Hanakawa3649.73
zaneb yaseen410.38
Cohen Leonardo G520.74