Does the cerebellum shape the spatiotemporal organization of muscle patterns? Insights from subjects with cerebellar ataxias

2020 ◽  
Vol 123 (5) ◽  
pp. 1691-1710 ◽  
Author(s):  
Denise J. Berger ◽  
Marcella Masciullo ◽  
Marco Molinari ◽  
Francesco Lacquaniti ◽  
Andrea d’Avella
Keyword(s):  
Muscle Activity ◽  
Activity Patterns ◽  
Specific Role ◽  
Modular Organization ◽  
Healthy Controls ◽  
Spatiotemporal Organization ◽  
Motor Commands ◽  
Cerebellar Damage ◽  
Cerebellar Ataxias ◽  
First Time

In recent studies, the decomposition of muscle activity patterns has revealed a modular organization of the motor commands. We show, for the first time, that muscle patterns of subjects with cerebellar damage share with healthy controls spatial, but not temporal and spatiotemporal, modules. Moreover, changes in spatiotemporal organization characterize the severity of the subject’s impairment. These results suggest that the cerebellum has a specific role in shaping the spatiotemporal organization of the muscle patterns.

scholarly journals Muscle activity while ambulating on stairs and slopes: A comparison between individuals scheduled and not scheduled for knee arthroplasty and healthy controls

2021 ◽  
Vol 52 ◽  
pp. 102346
Author(s):  
Vicktoria Elkarif ◽  
Leonid Kandel ◽  
Debbie Rand ◽  
Isabella Schwartz ◽  
Alexander Greenberg ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Muscle Activity ◽  
Healthy Controls

Soviet artist as a participant in the state funeral ritual of the 1920–1950s

2020 ◽  
pp. 16-21
Author(s):  
I. I. Rutsinskaya
Keyword(s):  
Emotional Reactions ◽  
The State ◽  
Specific Role ◽  
National Scale ◽  
Funeral Ritual ◽  
First Time

Throughout the 1920–1950s Selected Soviet artists were regular participants in state funeral ceremonies. In this article, for the first time, the process of including artists in a funeral ritual and investing them with a specific role in the performance of thanatological practices on a national scale is investigated. The stereotypes of behavior of those who were "honored" to be invited to the tomb of the leader, their emotional reactions, the nature of the work performed during the funeral ritual, are considered as components of the formation of a special semiotic space.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

scholarly journals Motor learning and transfer: from feedback to feedforward control

2019 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Motor Learning ◽  
Muscle Activity ◽  
Shoulder Joint ◽  
Stretch Reflex ◽  
Feedforward Control ◽  
Motor Task ◽  
Joint Torques ◽  
Motor Commands ◽  
Shoulder Muscle ◽  
Long Latency

AbstractPrevious work has demonstrated that when learning a new motor task, the nervous system modifies feedforward (ie. voluntary) motor commands and that such learning transfers to fast feedback (ie. reflex) responses evoked by mechanical perturbations. Here we show the inverse, that learning new feedback responses transfers to feedforward motor commands. Sixty human participants (34 females) used a robotic exoskeleton and either 1) received short duration mechanical perturbations (20 ms) that created pure elbow rotation or 2) generated self-initiated pure elbow rotations. They did so with the shoulder joint free to rotate (normal arm dynamics) or locked (altered arm dynamics) by the robotic manipulandum. With the shoulder unlocked, the perturbation evoked clear shoulder muscle activity in the long-latency stretch reflex epoch (50-100ms post-perturbation), as required for countering the imposed joint torques, but little muscle activity thereafter in the so-called voluntary response. After locking the shoulder joint, which alters the required joint torques to counter pure elbow rotation, we found a reliable reduction in the long-latency stretch reflex over many trials. This reduction transferred to feedforward control as we observed 1) a reduction in shoulder muscle activity during self-initiated pure elbow rotation trials and 2) kinematic errors (ie. aftereffects) in the direction predicted when failing to compensate for normal arm dynamics, even though participants never practiced self-initiated movements with the shoulder locked. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

Sign in / Sign up

Export Citation Format

Share Document