Corticospinal modulation induced by sounds depends on action preparedness

Welber Marinovic, James R. Tresilian, Aymar de Rugy, Simranjit Sidhu, Stephan Riek
The Journal of Physiology. 2013-10-25; 592(1): 153-169
DOI: 10.1113/jphysiol.2013.254581

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1. J Physiol. 2014 Jan 1;592(1):153-69. doi: 10.1113/jphysiol.2013.254581. Epub 2013
Sep 30.

Corticospinal modulation induced by sounds depends on action preparedness.

Marinovic W(1), Tresilian JR, de Rugy A, Sidhu S, Riek S.

Author information:
(1)W. Marinovic: School of Psychology, McElwain Building, St Lucia 4072,
Brisbane, QLD, Australia. .

A loud acoustic stimulus (LAS) presented during movement preparation can induce
an early release of the prepared action. Because loud sound has been found to
have an inhibitory effect on motor cortex excitability, it is possible that the
motor cortex plays little role in the early release of prepared responses. We
sought to shed new light on this suggestion by probing changes in corticospinal
excitability after LAS presentation during preparation for an anticipatory
action. Unexpectedly, we show that the changes in corticospinal excitability
after LAS presentation are not fixed. Based on the magnitude of motor-evoked
potentials elicited by transcranial magnetic and electric stimulation of the
motor cortex, we demonstrate that the effects of auditory stimuli on
corticospinal excitability depend on the level of readiness for action:
inhibition in early preparation and facilitation close to movement onset. We also
show that auditory stimuli can regulate intracortical excitability by increasing
intracortical facilitation and reducing short-interval intracortical inhibition.
Together, these findings indicate that, at least in part, the early release of
motor responses by auditory stimuli involves the motor cortex.

DOI: 10.1113/jphysiol.2013.254581
PMCID: PMC3903357
PMID: 24081157 [Indexed for MEDLINE]

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