posted on 2014-05-01, 14:41authored byAymeric Guillot, Frank Di Rienzo, Tadhg E. MacIntyre, Aidan P. Moran, Christine Collet
There is now compelling evidence that motor imagery (MI) and actual movement share
common neural substrate. However, the question of how MI inhibits the transmission of
motor commands into the efferent pathways in order to prevent any movement is largely
unresolved. Similarly, little is known about the nature of the electromyographic activity that
is apparent during MI. In addressing these gaps in the literature, the present paper argues
that MI includes motor execution commands for muscle contractions which are blocked
at some level of the motor system by inhibitory mechanisms. We first assemble data
from neuroimaging studies that demonstrate that the neural networks mediating MI and
motor performance are not totally overlapping, thereby highlighting potential differences
between MI and actual motor execution.We then review MI data indicating the presence
of subliminal muscular activity reflecting the intrinsic characteristics of the motor command
as well as increased corticomotor excitability. The third section not only considers
the inhibitory mechanisms involved during MI but also examines how the brain resolves
the problem of issuing the motor command for action while supervising motor inhibition
when people engage in voluntary movement during MI.The last part of the paper draws on
imagery research in clinical contexts to suggest that some patients move while imagining
an action, although they are not aware of such movements. In particular, experimental data
from amputees as well as from patients with Parkinson’s disease are discussed.We also
review recent studies based on comparing brain activity in tetraplegic patients with that
from healthy matched controls that provide insights into inhibitory processes during MI.
We conclude by arguing that based on available evidence, a multifactorial explanation of
motor inhibition during MI is warranted.
History
Publication
Frontiers in Human Neuroscience;6, Article 247
Publisher
Frontiers
Note
peer-reviewed
Rights
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