Awareness of muscular force during movement production: an fMRI study
Résumé
Awareness of the muscular forces we produce during voluntary
movement must be distinguished from awareness of motor outcome
itself. Indeed, there is no univocal relationship between produced
muscle force and movement outcome because of external forces. In
the present study, we performed a functional magnetic resonance
imaging study to investigate the neural bases underlying the
awareness we can have of the muscular forces we put into our
voluntary movements. In reference conditions, subjects made rhythmical
hand movements and knew they had to reproduce, in a
subsequent condition in which the resistance to the movement was
increased, either their muscular forces or their kinematics. The idea
behind this (well established) reproduction paradigm is that, after an
explicit verbal instruction, subjects can only reproduce what they are
aware off. The main contrast, that is, between the condition during
which the subjects had to gain awareness of their muscular forces and
that during which they had to gain awareness of their kinematics
(conditions in which the actual motor output was similar), shows that
gaining awareness about muscular forces exerted during movement
execution makes much higher demands on many brain structures, in
particular posterior insula, primary sensorimotor areas and associative
somatosensory areas. This indicates the important role of
somesthetic information processing in awareness of produced
muscular force. Therefore, the often-heard presumption that muscle
force sense might be based on the outgoing motor command is not
confirmed by the present results.
Domaines
Neurobiologie
Origine : Accord explicite pour ce dépôt
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