THE ROLE OF SENSORY INFORMATION IN THE GUIDANCE OF VOLUNTARY MOVEMENT- REFLECTIONS ON A SYMPOSIUM HELD AT THE 22ND ANNUAL-MEETING OF THE SOCIETY FOR NEUROSCIENCE
Di. Mccloskey et A. Prochazka, THE ROLE OF SENSORY INFORMATION IN THE GUIDANCE OF VOLUNTARY MOVEMENT- REFLECTIONS ON A SYMPOSIUM HELD AT THE 22ND ANNUAL-MEETING OF THE SOCIETY FOR NEUROSCIENCE, Somatosensory & motor research, 11(1), 1994, pp. 69-76
This article reviews a symposium on the sensory control of movement he
ld at the 22nd annual meeting of the Society for Neuroscience. Four sp
eakers addressed a large audience on the proposition that ''one can on
ly control what one senses.'' Charles Vierck supported the notion with
a description of the severe motor deficits caused by lesions of the s
pinal dorsal columns (DCs) in monkeys. In the discussion of Vierck's p
resentation, Robert Forget described the difficulties experienced by d
eafferented patients in tasks of daily life. Next, John Brooke showed
that sensorimotor transformations vary greatly with task, anticipation
, and uncertainty. In light of this, he questioned the simplifications
inherent in servo and equilibrium-point theories of motor control. Pa
ul Cordo then showed that in a rapid throwing task, proprioceptive inf
ormation is used to control the moment of release (contradicting the i
dea that sensory feedback is too delayed for ballistic movements). Dic
k Burgess, like Brooke, criticized equilibrium-point models; he argued
that a subject's sense of effort is a measure of the internal motor c
ommand, which should correspond to specific equilibrium points. Howeve
r, his experimental data were inconsistent with this interpretation. H
e suggested instead that motor output is adjusted by comparing incomin
g afferent information to an expected ''afferent template.'' Anatol Fe
ldman and Mark Latash disagreed, saying that a constant sense of effor
t does not imply a constant equilibrium-point command. The equilibrium
-point debate was not resolved, but the symposium ended with a consens
us that in most motor tasks, one can control only what one senses.