TY - JOUR
T1 - Distinct neural circuits for control of movement vs. Holding still
AU - Shadmehr, Reza
N1 - Funding Information:
I am grateful to Robi Soetedjo, Yoshiko Kojima, David Zee, David Herzfeld, and Scott Albert who provided comments on this manuscript. Support for this work was provided by grants from the National Institute of Neurological Disorders and Stroke (5R01NS078311) and the Office of Naval Research (N00014-15-1-2312).
Publisher Copyright:
© 2017 the American Physiological Society.
PY - 2017/4
Y1 - 2017/4
N2 - In generating a point-to-point movement, the brain does more than produce the transient commands needed to move the body part; it also produces the sustained commands that are needed to hold the body part at its destination. In the oculomotor system, these functions are mapped onto two distinct circuits: a premotor circuit that specializes in generating the transient activity that displaces the eyes and a “neural integrator” that transforms that transient input into sustained activity that holds the eyes. Different parts of the cerebellum adaptively control the motor commands during these two phases: the oculomotor vermis participates in fine tuning the transient neural signals that move the eyes, monitoring the activity of the premotor circuit via efference copy, whereas the flocculus participates in controlling the sustained neural signals that hold the eyes, monitoring the activity of the neural integrator. Here, I review the oculomotor literature and then ask whether this separation of control between moving and holding is a design principle that may be shared with other modalities of movement. To answer this question, I consider neurophysiological and psychophysical data in various species during control of head movements, arm movements, and locomotion, focusing on the brain stem, motor cortex, and hippocampus, respectively. The review of the data raises the possibility that across modalities of motor control, circuits that are responsible for producing commands that change the sensory state of a body part are distinct from those that produce commands that maintain that sensory state.
AB - In generating a point-to-point movement, the brain does more than produce the transient commands needed to move the body part; it also produces the sustained commands that are needed to hold the body part at its destination. In the oculomotor system, these functions are mapped onto two distinct circuits: a premotor circuit that specializes in generating the transient activity that displaces the eyes and a “neural integrator” that transforms that transient input into sustained activity that holds the eyes. Different parts of the cerebellum adaptively control the motor commands during these two phases: the oculomotor vermis participates in fine tuning the transient neural signals that move the eyes, monitoring the activity of the premotor circuit via efference copy, whereas the flocculus participates in controlling the sustained neural signals that hold the eyes, monitoring the activity of the neural integrator. Here, I review the oculomotor literature and then ask whether this separation of control between moving and holding is a design principle that may be shared with other modalities of movement. To answer this question, I consider neurophysiological and psychophysical data in various species during control of head movements, arm movements, and locomotion, focusing on the brain stem, motor cortex, and hippocampus, respectively. The review of the data raises the possibility that across modalities of motor control, circuits that are responsible for producing commands that change the sensory state of a body part are distinct from those that produce commands that maintain that sensory state.
KW - Brain stem
KW - Cerebellum
KW - Motor cortex
KW - Reaching
KW - Saccades
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U2 - 10.1152/jn.00840.2016
DO - 10.1152/jn.00840.2016
M3 - Review article
C2 - 28053244
AN - SCOPUS:85017025226
SN - 0022-3077
VL - 117
SP - 1431
EP - 1460
JO - Journal of neurophysiology
JF - Journal of neurophysiology
IS - 4
ER -