scholarly journals A motor planning stage represents the shape of upcoming movement trajectories

2016 ◽  
Vol 116 (2) ◽  
pp. 296-305 ◽  
Author(s):  
Aaron L. Wong ◽  
Jeff Goldsmith ◽  
John W. Krakauer
Keyword(s):  
Motor Planning ◽  
Time Cost ◽  
Planning Stage ◽  
Movement Trajectories ◽  
Motor Behaviors ◽  
Task Requirements ◽  
Trajectory Representation ◽  
Stimulus Perception ◽  
Human Motor ◽  
Point To Point

Interactions with our environment require curved movements that depend not only on the final position of the hand but also on the path used to achieve it. Current studies in motor control, however, largely focus on point-to-point movements and do not consider how movements with specific desired trajectories might arise. In this study, we examined intentionally curved reaching movements that navigate paths around obstacles. We found that the preparation of these movements incurred a large reaction-time cost. This cost could not be attributed to nonmotor task requirements (e.g., stimulus perception) and was independent of the execution difficulty (i.e., extent of curvature) of the movement. Additionally, this trajectory representation cost was not observed for point-to-point reaches but could be optionally included if the task encouraged consideration of straight trajectories. Therefore, when the path of a movement is task relevant, the shape of the desired trajectory is overtly represented as a stage of motor planning. This trajectory representation ability may help explain the vast repertoire of human motor behaviors.

Control Mechanisms in Oscillatory Motor Behavior

2013 ◽  
Author(s):  
Davide Piovesan ◽  
Felix C. Huang
Keyword(s):  
Muscle Activation ◽  
Motor Behavior ◽  
Rhythmic Movement ◽  
Control Mechanisms ◽  
Rhythmic Movements ◽  
Movement Trajectories ◽  
Reduced Frequency ◽  
The Central Nervous System ◽  
Human Motor ◽  
Inertial Loading

Studies on unimpaired humans have demonstrated that the central nervous system employs internal representations of limb dynamics and intended movement trajectories for planning muscle activation during pointing and reaching tasks. However, when performing rhythmic movements, it has been hypothesized that a control scheme employing an autonomous oscillator — a simple feedback circuit lacking exogenous input — can maintain stable control. Here we investigate whether such simple control architectures that can realize rhythmic movement that we observe in experimental data. We asked subjects to perform rhythmic movements of the forearm while a robotic interface simulated inertial loading. Our protocol included unexpected increases in loading (catch trials) as a probe to reveal any systematic changes in frequency and amplitude. Our primary findings were that increased inertial loading resulted in reduced frequency of oscillations, and in some cases multiple frequencies. These results exhibit some agreement with an autonomous oscillator model, though other features are more consistent with feedforward planning of force. This investigation provides a theoretical and experimental framework to reveal basic computational elements for how the human motor system achieves skilled rhythmic movement.

scholarly journals Cue-related Temporal Factors Modulate Movement-related Beta Oscillatory Activity in the Human Motor Circuit

2016 ◽  
Vol 28 (7) ◽  
pp. 1039-1051 ◽  
Author(s):  
Elizabeth Heinrichs-Graham ◽  
David J. Arpin ◽  
Tony W. Wilson
Keyword(s):  
Premotor Cortex ◽  
Motor Planning ◽  
Oscillatory Activity ◽  
Planning Time ◽  
Motor Circuit ◽  
Cortical Motor ◽  
Temporal Factors ◽  
Human Motor ◽  
Study Participants ◽  
Parietal Cortices

In humans, there is a strong beta (15–30 Hz) event-related desynchronization (ERD) that begins before movement, which has been tentatively linked to motor planning operations. The dynamics of this response are strongly modulated by whether a pending movement is cued and the inherent parameters of the cue. However, previous studies have focused on the information content of cues and not on parameters such as the timing of the cue relative to other events. Variations in such timing are critical, as they directly impact the amount of time that participants have to plan pending movements. In this study, participants performed finger-tapping sequences during magnetoencephalography, and we manipulated the amount of time (i.e., “long” vs. “short”) between the presentation of the to-be-executed sequence and the cue to initiate the sequence. We found that the beta ERD was stronger immediately after the cue to move in the contralateral postcentral gyrus and bilateral parietal cortices during the short compared with long planning time condition. During movement execution, the beta ERD was stronger in the premotor cortex and the SMA in the short relative to long condition. Finally, peak latency in the SMA significantly correlated with RT, such that the closer the peak beta ERD was to the cue to move, the quicker the participant responded. The results of this study establish that peri-movement beta ERD activity across the cortical motor circuit is highly sensitive to cue-related temporal factors, with a direct link to motor performance.

scholarly journals Evidence for Multisensory Spatial-to-Motor Transformations in Aiming Movements of Children

2009 ◽  
Vol 101 (1) ◽  
pp. 315-322 ◽  
Author(s):  
Bradley R. King ◽  
Florian A. Kagerer ◽  
Jose L. Contreras-Vidal ◽  
Jane E. Clark
Keyword(s):  
Motor Coordination ◽  
Age Groups ◽  
Motor Planning ◽  
Visuomotor Rotation ◽  
Visuomotor Coordination ◽  
Aiming Movements ◽  
Movement Trajectories ◽  
Acoustic Stimuli ◽  
Age Related ◽  
Before And After

The extant developmental literature investigating age-related differences in the execution of aiming movements has predominantly focused on visuomotor coordination, despite the fact that additional sensory modalities, such as audition and somatosensation, may contribute to motor planning, execution, and learning. The current study investigated the execution of aiming movements toward both visual and acoustic stimuli. In addition, we examined the interaction between visuomotor and auditory-motor coordination as 5- to 10-yr-old participants executed aiming movements to visual and acoustic stimuli before and after exposure to a visuomotor rotation. Children in all age groups demonstrated significant improvement in performance under the visuomotor perturbation, as indicated by decreased initial directional and root mean squared errors. Moreover, children in all age groups demonstrated significant visual aftereffects during the postexposure phase, suggesting a successful update of their spatial-to-motor transformations. Interestingly, these updated spatial-to-motor transformations also influenced auditory-motor performance, as indicated by distorted movement trajectories during the auditory postexposure phase. The distorted trajectories were present during auditory postexposure even though the auditory-motor relationship was not manipulated. Results suggest that by the age of 5 yr, children have developed a multisensory spatial-to-motor transformation for the execution of aiming movements toward both visual and acoustic targets.

scholarly journals Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback

2013 ◽  
Vol 109 (4) ◽  
pp. 1126-1139 ◽  
Author(s):  
Dinant A. Kistemaker ◽  
Arthur J. Knoek Van Soest ◽  
Jeremy D. Wong ◽  
Isaac Kurtzer ◽  
Paul L. Gribble
Keyword(s):  
Optimal Control ◽  
Muscle Spindle ◽  
Muscle Spindles ◽  
Ample Evidence ◽  
Golgi Tendon Organs ◽  
Position Errors ◽  
Musculoskeletal Models ◽  
Human Motor ◽  
Tendon Organs ◽  
Point To Point

Whereas muscle spindles play a prominent role in current theories of human motor control, Golgi tendon organs (GTO) and their associated tendons are often neglected. This is surprising since there is ample evidence that both tendons and GTOs contribute importantly to neuromusculoskeletal dynamics. Using detailed musculoskeletal models, we provide evidence that simple feedback using muscle spindles alone results in very poor control of joint position and movement since muscle spindles cannot sense changes in tendon length that occur with changes in muscle force. We propose that a combination of spindle and GTO afferents can provide an estimate of muscle-tendon complex length, which can be effectively used for low-level feedback during both postural and movement tasks. The feasibility of the proposed scheme was tested using detailed musculoskeletal models of the human arm. Responses to transient and static perturbations were simulated using a 1-degree-of-freedom (DOF) model of the arm and showed that the combined feedback enabled the system to respond faster, reach steady state faster, and achieve smaller static position errors. Finally, we incorporated the proposed scheme in an optimally controlled 2-DOF model of the arm for fast point-to-point shoulder and elbow movements. Simulations showed that the proposed feedback could be easily incorporated in the optimal control framework without complicating the computation of the optimal control solution, yet greatly enhancing the system's response to perturbations. The theoretical analyses in this study might furthermore provide insight about the strong physiological couplings found between muscle spindle and GTO afferents in the human nervous system.

Point-to-point learning in human motor systems

2013 ◽  
Author(s):  
Shou-Han Zhou ◽  
Ying Tan ◽  
Denny Oetomo ◽  
Chris Freeman ◽  
Etienne Burdet ◽  
...  
Keyword(s):  
Motor Systems ◽  
Human Motor ◽  
Point To Point

scholarly journals Immediate tool incorporation processes determine human motor planning with tools

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
G. Ganesh ◽  
T. Yoshioka ◽  
R. Osu ◽  
T. Ikegami
Keyword(s):  
Motor Planning ◽  
Human Motor
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