The brain: seat of motor control∗: Corticospinal neurones in movement performance

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

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New Technologies of Motor Control and Rehabilitation

Reabilitacijos mokslai slauga kineziterapija ergoterapija ◽

10.33607/rmske.v1i1.890 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Albertas Skurvydas

Keyword(s):

Motor Control ◽

New Technologies ◽

Modern Science ◽

Computational Approach ◽

Neural Cells ◽

Motor Rehabilitation ◽

Principal Mechanism ◽

Brain Stroke ◽

Computational Paradigm ◽

The Brain

Modern paradigms of motor control and rehabilitation are analyzed in the paper. Two main paradigms, i. e. computational approach and dynamical system approach are engaged in rivalry in motor control and learning research at present. From the standpoint of computational paradigm the principal mechanism of motor control and learning consists in the ability of the brain “to calculate” (acting as some kind of biological computer). According to the paradigm of dynamical systems the mechanism of motor control is time dependent. In other words, it can be different each time. The main principles of motor control and properties of movements are given considerable attention in the paper. Besides, modern methods of motor rehabilitation after stroke are emphasized in the paper. Fitting of neuroprosthesis and restoration of damaged neural cells are significant maiden steps in modern science. The scientists are engaged in search for: a) constraining such mechanism prosthesis that would submit to the efforts of human will and b) restoring neural cells damaged because of the brain stroke suffered.Keywords: motor control, rehabilitation, stroke.

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An action-oriented perspective on space and affordances

10.1093/med/9780190060954.003.0002 ◽

2021 ◽

pp. 73-140

Author(s):

Michael A. Arbib

Keyword(s):

Motor Control ◽

Body Schema ◽

Cognitive Maps ◽

The Body ◽

Perceptual Cues ◽

Motor Patterns ◽

General Rules ◽

Hand Eye Coordination ◽

Ongoing Behavior ◽

The Brain

Architects design spaces that offer perceptual cues, affordances, for our various effectivities. Lina Bo Bardi’s São Paulo Museum demonstrates how praxic and contemplative actions are interleaved—space is effective and affective. Navigation often extends beyond wayfinding to support ongoing behavior. Scripts set out the general rules for a particular kind of behavior, and may suggest places that a building must provide. Cognitive maps support wayfinding. Other maps in the brain represent sensory or motor patterns of activity. Juhani Pallasmaa’s reflections on The Thinking Hand lead into a view of how the brain mediates that thinking, modeling hand–eye coordination at two levels. The first coordinates perceptual and motor schemas. The body schema is an adaptable collage of perceptual and motor skills. The second coordinates the ventral “what” pathway that can support planning of actions, and the dorsal “how” pathway that links affordance-related details to motor control. A complementary challenge is understanding how schemas in the head relate to social schemas. Finally, the chapter compares the cognitive challenges in designing a building and in developing a computational brain model of cognitive processes.

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2. The human brain

Consciousness: A Very Short Introduction ◽

10.1093/actrade/9780198794738.003.0002 ◽

2017 ◽

pp. 17-33

Author(s):

Susan Blackmore

Keyword(s):

Body Image ◽

Motor Control ◽

Human Brain ◽

Brain Function ◽

The Self ◽

Central Processor ◽

Human Consciousness ◽

The Brain ◽

Vast Network ◽

Successful Science

‘The human brain’ considers the brain as a vast network of connections from which come our extraordinary abilities: perception, learning, memory, reasoning, language, and somehow or another—consciousness. Different areas deal with vision, hearing, speech, body image, motor control, and forward planning. They are all linked, but this is not done through one central processor, but by millions of criss-crossing connections. By contrast, human consciousness seems to be unified. A successful science of consciousness must therefore explain the contents of consciousness, the continuity of consciousness, and the self who is conscious. Research linking consciousness to brain function is discussed along with conditions such as synaesthesia, blindsight, stroke damage, and amnesia.

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Diabetes Mellitus-Related Dysfunction of the Motor System

International Journal of Molecular Sciences ◽

10.3390/ijms21207485 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7485

Author(s):

Ken Muramatsu

Keyword(s):

Motor Control ◽

Motor Neurons ◽

Motor System ◽

Corticospinal Tract ◽

Experimental Studies ◽

Sensory System ◽

Treatment Strategies ◽

Motor Deficits ◽

New Perspective ◽

The Brain

Although motor deficits in humans with diabetic neuropathy have been extensively researched, its effect on the motor system is thought to be lesser than that on the sensory system. Therefore, motor deficits are considered to be only due to sensory and muscle impairment. However, recent clinical and experimental studies have revealed that the brain and spinal cord, which are involved in the motor control of voluntary movement, are also affected by diabetes. This review focuses on the most important systems for voluntary motor control, mainly the cortico-muscular pathways, such as corticospinal tract and spinal motor neuron abnormalities. Specifically, axonal damage characterized by the proximodistal phenotype occurs in the corticospinal tract and motor neurons with long axons, and the transmission of motor commands from the brain to the muscles is impaired. These findings provide a new perspective to explain motor deficits in humans with diabetes. Finally, pharmacological and non-pharmacological treatment strategies for these disorders are presented.

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Output Units of Motor Behavior: An Experimental and Modeling Study

Journal of Cognitive Neuroscience ◽

10.1162/08989290051137611 ◽

2000 ◽

Vol 12 (1) ◽

pp. 78-97 ◽

Cited By ~ 30

Author(s):

E. P. Loeb ◽

S. F. Giszter ◽

P. Saltiel and E. Bizzi ◽

F. A. Mussa-Ivaldi

Keyword(s):

Motor Control ◽

Common Property ◽

Motor Behavior ◽

Muscle Synergies ◽

Force Output ◽

Time Dynamics ◽

Motor Behaviors ◽

Distinct Property ◽

Small Set ◽

The Brain

Cognitive approaches to motor control typically concern sequences of discrete actions without taking into account the stunning complexity of the geometry and dynamics of the muscles. This begs the question: Does the brain convert the intricate, continuous-time dynamics of the muscles into simpler discrete units of actions, and if so, how? One way for the brain to form discrete units of behavior from muscles is through the synergistic co-activation of muscles. While this possibility has long been known, the composition of potential muscle synergies has remained elusive. In this paper, we have focused on a method that allowed us to examine and compare the limb stabilization properties of all possible muscle combinations. We found that a small set (as few as 23 out of 65,536) of all possible combinations of 16 limb muscles are robust with respect to activation noise: these muscle combinations could stabilize the limb at predictable, restricted portions of the workspace in spite of broad variations in the force output of their component muscles. The locations at which the robust synergies stabilize the limb are not uniformly distributed throughout the leg's workspace, but rather, they cluster at four workspace areas. The simulated robust synergies are similar to the actual synergies we have previously found to be generated by activation of the spinal cord. Thus, we have developed a new analytical method that enabled us to select a few muscle synergies with interesting properties out of the set of possible muscle combinations. Beyond this, the identification of robustness as a common property of the synergies in simple motor behaviors will open the way to the study of dynamic stability, which is an important and distinct property of the vertebrate motor-control system.

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Motor control: spinal and cortical mechanisms

10.1093/med/9780199688395.003.0003 ◽

2016 ◽

Author(s):

David Burke

Keyword(s):

Motor Control ◽

Motor Cortex ◽

Voluntary Movement ◽

Primary Motor Cortex ◽

Lower Limbs ◽

Spinal Reflex ◽

Extensive Literature ◽

Spinal Level ◽

Corticospinal System ◽

The Brain

There is extensive machinery at cerebral and spinal levels to support voluntary movement, but spinal mechanisms are often ignored by clinicians and researchers. For movements of the upper and lower limbs, what the brain commands can be modified or even suppressed completely at spinal level. The corticospinal system is the executive pathway for movement arising largely from primary motor cortex, but movement is not initiated there, and other pathways normally contribute to movement. Greater use of these pathways can allow movement to be restored when the corticospinal system is damaged by, e.g. stroke, but there can be unwanted consequences of this ‘plasticity’. There is an extensive literature on cerebral mechanisms in the control of movement, and an equally large literature on spinal reflex function and the changes that occur during movement, and when pathology results in weakness and/or spasticity.

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Do We Have a “Mental Syllabary” in the Brain? An fMRI Study

Motor Control ◽

10.1123/mcj.15.1.34 ◽

2011 ◽

Vol 15 (1) ◽

pp. 34-51 ◽

Cited By ~ 15

Author(s):

Bettina Brendel ◽

Michael Erb ◽

Axel Riecker ◽

Wolfgang Grodd ◽

Hermann Ackermann ◽

...

Keyword(s):

Motor Control ◽

Low Frequency ◽

Frequency Effect ◽

Speech Motor Control ◽

Motor Execution ◽

Syllable Frequency ◽

Fmri Study ◽

The Brain ◽

Speech Motor

The present study combines functional magnetic resonance imaging (fMRI) and reaction time (RT) measurements to further elucidate the influence of syllable frequency and complexity on speech motor control processes, i.e., overt reading of pseudowords. Tying in with a recent fMRI-study of our group we focused on the concept of a mental syllabary housing syllable sized ready-made motor plans for high- (HF), but not low-frequency (LF) syllables. The RT-analysis disclosed a frequency effect weakened by a simultaneous complexity effect for HF-syllables. In contrast, the fMRI data revealed no effect of syllable frequency, but point to an impact of syllable structure: Compared with CV-items, syllables with a complex onset (CCV) yielded higher hemodynamic activation in motor “execution” areas (left sensorimotor cortex, right inferior cerebellum), which is at least partially compatible with our previous study. We discuss the role of the syllable in speech motor control.

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Music, motor control and the brain

Brain ◽

10.1093/brain/awl231 ◽

2006 ◽

Vol 129 (10) ◽

pp. 2794-2798 ◽

Cited By ~ 1

Author(s):

K. V. Toyka

Keyword(s):

Motor Control ◽

The Brain

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Spatial constancy mechanisms in motor control

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2010.0089 ◽

2011 ◽

Vol 366 (1564) ◽

pp. 476-491 ◽

Cited By ~ 44

Author(s):

W. Pieter Medendorp

Keyword(s):

Motor Control ◽

Eye Movements ◽

Three Dimensional ◽

Spatial Updating ◽

Feedback Processing ◽

Feed Forward ◽

Motor Information ◽

Induced Motion ◽

Forward Process ◽

The Brain

The success of the human species in interacting with the environment depends on the ability to maintain spatial stability despite the continuous changes in sensory and motor inputs owing to movements of eyes, head and body. In this paper, I will review recent advances in the understanding of how the brain deals with the dynamic flow of sensory and motor information in order to maintain spatial constancy of movement goals. The first part summarizes studies in the saccadic system, showing that spatial constancy is governed by a dynamic feed-forward process, by gaze-centred remapping of target representations in anticipation of and across eye movements. The subsequent sections relate to other oculomotor behaviour, such as eye–head gaze shifts, smooth pursuit and vergence eye movements, and their implications for feed-forward mechanisms for spatial constancy. Work that studied the geometric complexities in spatial constancy and saccadic guidance across head and body movements, distinguishing between self-generated and passively induced motion, indicates that both feed-forward and sensory feedback processing play a role in spatial updating of movement goals. The paper ends with a discussion of the behavioural mechanisms of spatial constancy for arm motor control and their physiological implications for the brain. Taken together, the emerging picture is that the brain computes an evolving representation of three-dimensional action space, whose internal metric is updated in a nonlinear way, by optimally integrating noisy and ambiguous afferent and efferent signals.

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