A Cortico-Spinal Model of Reaching and Proprioception under Multiple Task Constraints

1998 ◽  
Vol 10 (4) ◽  
pp. 425-444 ◽  
Author(s):  
Paul Cisek ◽  
Stephen Grossberg ◽  
Daniel Bullock
Keyword(s):  
Movement Control ◽  
Arm Movement ◽  
Movement Speed ◽  
Dynamic Feedback ◽  
Range Of Movement ◽  
Tonic Vibration Reflex ◽  
Task Constraints ◽  
Feedback Information ◽  
Wide Range ◽  
The Brain

A model of cortico-spinal trajectory generation for voluntary reaching movements is developed to functionally interpret a broad range of behavioral, physiological, and anatomical data. The model simulates how arm movements achieve their remarkable efficiency and accuracy in response to widely varying positional, speed, and force constraints. A key issue in arm movement control is how the brain copes with such a wide range of movement contexts. The model suggests how the brain may set automatic and volitional gating mechanisms to vary the balance of static and dynamic feedback information to guide the movement command and to compensate for external forces. For example, with increasing movement speed, the system shifts from a feedback position controller to a feedforward trajectory generator with superimposed dynamics compensation. Simulations of the model illustrate how it reproduces the effects of elastic loads on fast movements, endpoint errors in Coriolis fields, and several effects of muscle tendon vibration, including tonic and antagonist vibration reflexes, position and movement illusions, effects of obstructing the tonic vibration reflex, and reaching undershoots caused by antagonist vibration.

scholarly journals Can proprioceptive training improve motor learning?

2012 ◽  
Vol 108 (12) ◽  
pp. 3313-3321 ◽  
Author(s):  
Jeremy D. Wong ◽  
Dinant A. Kistemaker ◽  
Alvin Chin ◽  
Paul L. Gribble
Keyword(s):  
Motor Learning ◽  
Visual Information ◽  
Movement Control ◽  
Arm Movement ◽  
Sensory Function ◽  
Movement Speed ◽  
Active Movement ◽  
Positional Accuracy ◽  
Control Subjects ◽  
Proprioceptive Training

Recent work has investigated the link between motor learning and sensory function in arm movement control. A number of findings are consistent with the idea that motor learning is associated with systematic changes to proprioception (Haith A, Jackson C, Mial R, Vijayakumar S. Adv Neural Inf Process Syst 21: 593–600, 2008; Ostry DJ, Darainy M, Mattar AA, Wong J, Gribble PL. J Neurosci 30: 5384–5393, 2010; Vahdat S, Darainy M, Milner TE, Ostry DJ. J Neurosci 31: 16907–16915, 2011). Here, we tested whether motor learning could be improved by providing subjects with proprioceptive training on a desired hand trajectory. Subjects were instructed to reproduce both the time-varying position and velocity of novel, complex hand trajectories. Subjects underwent 3 days of training with 90 movement trials per day. Active movement trials were interleaved with demonstration trials. For control subjects, these interleaved demonstration trials consisted of visual demonstration alone. A second group of subjects received visual and proprioceptive demonstration simultaneously; this group was presented with the same visual stimulus, but, in addition, their limb was moved through the target trajectory by a robot using servo control. Subjects who experienced the additional proprioceptive demonstration of the desired trajectory showed greater improvements during training movements than control subjects who only received visual information. This benefit of adding proprioceptive training was seen in both movement speed and position error. Interestingly, additional control subjects who received proprioceptive guidance while actively moving their arm during demonstration trials did not show the same improvement in positional accuracy. These findings support the idea that the addition of proprioceptive training can augment motor learning, and that this benefit is greatest when the subject passively experiences the goal movement.

Organizing principles for single joint movements. III. Speed-insensitive strategy as a default

1990 ◽  
Vol 63 (3) ◽  
pp. 625-636 ◽  
Author(s):  
G. L. Gottlieb ◽  
D. M. Corcos ◽  
G. C. Agarwal ◽  
M. L. Latash
Keyword(s):  
Human Subjects ◽  
Movement Control ◽  
Initial Position ◽  
Initial Slope ◽  
Range Of Movement ◽  
Stationary Target ◽  
Wide Range ◽  
Inertial Torque ◽  
Maximal Speed ◽  
Speed Accuracy

1. Human subjects made discrete elbow flexions in a horizontal plane over different distances, from a stationary initial position to a visually defined stationary target 9 degrees wide. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles. 2. Subjects made movements over four different distances following one of four different instructions. The first instructed the subject simply to choose a comfortable speed. The other three explicitly emphasized either speed, accuracy, or maintenance of the "same" speed over different distances. These instructions produced a wide range of movement velocities. 3. The initial rises of the acceleration (and therefore of the inertial torque), as well as the initial slope of the agonist EMG, were all invariant over changes in the target distance for any single instruction but were all sensitive to the given instruction. 4. Our results demonstrate that the speed-insensitive strategy is a standard or default pattern for performing movements that may be carried out for different instructions over a wide range of speeds. A uniform intensity of excitation pulse is not a byproduct of moving at maximal speed. Submaximal intensities are associated with submaximal speeds and are a selected feature of the pattern of movement control.

Tai Chi Practice Improves Senior Citizens’ Balance and Arm Movement Control

1998 ◽  
Vol 6 (3) ◽  
pp. 271-284 ◽  
Author(s):  
Jin H. Yan
Keyword(s):  
Tai Chi ◽  
Balance Control ◽  
Senior Citizens ◽  
Dynamic Balance ◽  
Exercise Program ◽  
Arm Movements ◽  
Movement Control ◽  
Arm Movement ◽  
Movement Speed ◽  
Locomotor Activities

Empirical evidence from this study supports the hypothesis that Tai Chi practice can improve senior citizens’ dynamic balance control and rapid-aiming arm movement performance. Of 38 senior citizens, 28 (M = 78.8 years. SD = 2.1) chose to practice the 24-form simplified Tai Chi. The remaining 10 seniors (M = 79.2 years. SD = 1.9) selected a locomotor activity (walking or jogging). Dynamic balance tests and ballistic-aiming arm movements were conducted for all participants at the beginning, middle (4th week), and end of the 8-week exercise program. The Tai Chi participants improved their time on balance more than did their counterparts who performed locomotor activities. In addition, Tai Chi practice improved arm movement smoothness to a greater extent than the locomotor activities. However, no changes in arm movement speed were observed in either group. The results suggest that Tai Chi practice may help senior citizens improve dynamic balance control and gain smoothness in rapid-aiming arm movements.

scholarly journals Neuroprosthetic Devices: i-HAND

2019 ◽  
Vol 4 (4) ◽  
Keyword(s):  
Movement Control ◽  
Specific Area ◽  
Body Part ◽  
The Body ◽  
Robot Arm ◽  
Prosthetic Limb ◽  
Wide Range ◽  
Cord Injury ◽  
Neuroprosthetic Devices ◽  
The Brain

Millions of people are paralyzed or have suffered an amputation. Although these people can still see the object they may want to reach, for example a glass of wine, and can still process in their brains the specific commands to pursue this goal, the action cannot be completed due to, for example, a spinal cord injury or due to the fact that the arm has been amputated. Given that in most cases the brain of these persons is intact, the possibility of reading brain signals would allow the development of Neuroprosthetic devices, such as a robot arm that is driven by neural activity. These technological and scientific advances connect the amputee more intimately with their prosthetic limb, meaning we can now focus more on how the prosthesis is embodied. In other words, to what extent does the prosthetic limb feel like part of the biological body? Does your brain treat it as such? We have a good understanding of how our body is mapped in our brain. Both our motor cortex – the movement control centre, if you like – and the somatosensory cortex where we process a wide range of touch sensations are organisedsomatotopically. This means each area of our body corresponds to a specific area of the primary motor and sensory cortices. Importantly, this mapping does not disappear after the loss of a limb. This means we have an opportunity to connect prostheses, through muscles and peripheral nerves, to the parts of the brain that would have controlled and sensed the biological body part. But it may also allow us to measure embodiment, how successfully the brain accepts the prosthesis as part of the body. Ultimately this line of research, bringing together cognitive neuroscience and biomedical engineering, is not only important for designing better prostheses. It is a unique window for understanding how our brain creates and maintains the image of our bodies – mechanisms that apply equally to amputees and non-amputees.

Movement Control Phases of Upper Body Coordination in Visually Guided Reach Movements

2009 ◽  
Vol 53 (12) ◽  
pp. 834-838
Author(s):  
Shin-Yuan Yu ◽  
Bernard J. Martin
Keyword(s):  
Motor Behavior ◽  
Peak Velocity ◽  
Movement Time ◽  
Movement Control ◽  
Human Movement ◽  
Upper Body ◽  
Movement Speed ◽  
Joint Movement ◽  
Feedback Information ◽  
Time To Peak

Coordination of human movement includes temporal and spatial aspects. Under the assumption that the implicit movement sequence of body segments may be associated with visual feedback information, the activation timing, time to peak velocity of the hand and sequencing of joint movements were investigated in this study. The results show that variations in movement time with target azimuth and distance fit a quadratic regression model. In addition, the time to peak velocity reveals a movement scaling property in the context of self-imposed movement speed. Finally, the sequencing of joint movement also varies with target azimuth and distance. These motor behavior properties and movement characteristics can be used to model human reach movement in a dynamic manner and to estimate task durations.

Sensitivity Analysis of Dynamics System in the Upper Limb Movement Control

2012 ◽  
Author(s):  
Kai Chen ◽  
Richard A. Foulds
Keyword(s):  
Sensitivity Analysis ◽  
Upper Limb ◽  
Impedance Control ◽  
Muscle Length ◽  
Movement Control ◽  
Arm Movement ◽  
Human Movement ◽  
Limb Movement ◽  
Feedback Information ◽  
Analysis Of Dynamics

The dependence of muscle force on muscle length gives rise to a “spring–like” behavior which has been shown to play an important role during human movement. Neville Hogan (Hogan, 1985) proposed a mathematical model in terms of impedance control of arm movement. Discussing this work, Dr. Hogan admits that it can not effectively model all aspects of the performance of the system. He said “Controlling the complete dynamic behavior of the limb may be beyond the capacity of the central nervous system. If the disturbance is sufficiently abrupt, then, because of the inevitable transmission delays, continuous intervention based on neural feedback information will not be a feasible method of modulating these quantities.”. However, the model proposed in this study, accomplished most the work which Hogan believed was not feasible. In order to validate the result of proposed model, this study perform sensitivity analysis between the results produced by the dynamics system and the results measured, the comparison showed the difference between these two results were less than 10%, which strongly support the idea that proposed dynamic model can accurately reflect dynamics system in the upper limb movement control.

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

scholarly journals Bio-Inspired Modality Fusion for Active Speaker Detection

2021 ◽  
Vol 11 (8) ◽  
pp. 3397
Author(s):  
Gustavo Assunção ◽  
Nuno Gonçalves ◽  
Paulo Menezes
Keyword(s):  
Superior Colliculus ◽  
Visual Information ◽  
Human Beings ◽  
Validation Process ◽  
Detection Approach ◽  
Wide Range ◽  
Speaker Detection ◽  
The One ◽  
The Brain ◽  
Fusion Ability

Human beings have developed fantastic abilities to integrate information from various sensory sources exploring their inherent complementarity. Perceptual capabilities are therefore heightened, enabling, for instance, the well-known "cocktail party" and McGurk effects, i.e., speech disambiguation from a panoply of sound signals. This fusion ability is also key in refining the perception of sound source location, as in distinguishing whose voice is being heard in a group conversation. Furthermore, neuroscience has successfully identified the superior colliculus region in the brain as the one responsible for this modality fusion, with a handful of biological models having been proposed to approach its underlying neurophysiological process. Deriving inspiration from one of these models, this paper presents a methodology for effectively fusing correlated auditory and visual information for active speaker detection. Such an ability can have a wide range of applications, from teleconferencing systems to social robotics. The detection approach initially routes auditory and visual information through two specialized neural network structures. The resulting embeddings are fused via a novel layer based on the superior colliculus, whose topological structure emulates spatial neuron cross-mapping of unimodal perceptual fields. The validation process employed two publicly available datasets, with achieved results confirming and greatly surpassing initial expectations.

Whole-body adaptation to novel dynamics does not transfer between effectors

2021 ◽  
Author(s):  
Alison Pienciak-Siewert ◽  
Alaa A Ahmed
Keyword(s):  
Postural Control ◽  
Arm Movement ◽  
Movement Planning ◽  
Reaching Movements ◽  
Whole Body ◽  
Postural Control System ◽  
Movement Dynamics ◽  
Gradual Introduction ◽  
Postural Movement ◽  
The Brain

How does the brain coordinate concurrent adaptation of arm movements and standing posture? From previous studies, the postural control system can use information about previously adapted arm movement dynamics to plan appropriate postural control; however, it is unclear whether postural control can be adapted and controlled independently of arm control. The present study addresses that question. Subjects practiced planar reaching movements while standing and grasping the handle of a robotic arm, which generated a force field to create novel perturbations. Subjects were divided into two groups, for which perturbations were introduced in either an abrupt or gradual manner. All subjects adapted to the perturbations while reaching with their dominant (right) arm, then switched to reaching with their non-dominant (left) arm. Previous studies of seated reaching movements showed that abrupt perturbation introduction led to transfer of learning between arms, but gradual introduction did not. Interestingly, in this study neither group showed evidence of transferring adapted control of arm or posture between arms. These results suggest primarily that adapted postural control cannot be transferred independently of arm control in this task paradigm. In other words, whole-body postural movement planning related to a concurrent arm task is dependent on information about arm dynamics. Finally, we found that subjects were able to adapt to the gradual perturbation while experiencing very small errors, suggesting that both error size and consistency play a role in driving motor adaptation.

Senses of Vibration

2012 ◽  
Author(s):  
Shelly Trower
Keyword(s):  
Sensory Experience ◽  
Cultural Imaginary ◽  
Wide Range ◽  
History Of ◽  
The Senses ◽  
To Come ◽  
The Brain

The study of the senses has become a rich topic in recent years. Senses of Vibration explores a wide range of sensory experience and makes a decisive new contribution to this growing field by focussing not simply on the senses as such, but on the material experience - vibration - that underpins them. This is the first book to take the theme of vibration as central, offering an interdisciplinary history of the phenomenon and its reverberations in the cultural imaginary. It tracks vibration through the work of a wide range of writers, including physiologists (who thought vibrations in the nerves delivered sensations to the brain), physicists (who claimed that light, heat, electricity and other forms of energy were vibratory), spiritualists (who figured that spiritual energies also existed in vibratory form), and poets and novelists from Coleridge to Dickens and Wells. Senses of Vibration is a work of scholarship that cuts through a range of disciplines and will reverberate for many years to come.

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