Seminars in Motor Control

Mark L. Latash approaches motor control as a biological discipline that requires the language of laws of nature, sets of adequate concepts specific for biological movement, and exploration using the scientific method developed in natural science.

Seminars in Motor Control introduces and develops the theory of the parametric control of movement with spatial referent coordinates – a generalization of the equilibrium-point hypothesis – which is naturally compatible with the principle of abundance and the uncontrolled manifold hypothesis. The chapters discuss potential neurophysiological mechanisms involved in ensuring stability of functional movements and the relations among movement stability, agility, and optimality. The author addresses issues such as posture-movement paradox, equifinality and its violations, motor equivalence, muscle coactivation, multi-muscle and intra-muscle synergies, unintentional drifts in performance, kinesthetic perception, changes in movements with fatigue, aging, motor learning, neurological disorders, and rehabilitation.

Consisting of five parts, Seminars in Motor Control examines current research in a clear and accessible style, ideal for graduate students, postdoctoral fellows, and faculty in such departments as kinesiology, neuroscience, physiology, psychology, and physical therapy.

• Features a detailed discussion of poorly understood concepts such as control with referent coordinates, synergy, uncontrolled manifold, etc.
• Includes a coherent exposition of the recent progress in motor control as an area of natural science
• Provides a unique exposition of the recent theories on the neural control of movement and their applications

CONTENTS

Preface
Part I: Basic Concepts
Chapter 1: Philosophy
1.1. Laws of nature in the inanimate world
1.2. Specificity of living objects
1.3. Stretch reflex as a biological law of nature
1.4. How many sets of laws of nature are there?
1.5. Missing pieces of the mosaic
Chapter 2: Bernstein’s construction of movements
2.1. Nikolai Bernstein: Philosopher and experimentalist
2.2. The evolutionary approach to movement construction
2.3. Problem of motor redundancy
2.4. Sharing and optimality
2.5. Missing pieces of the mosaic
Chapter 3: Equilibrium-point (EP) hypothesis
3.1. Roots of the EP hypothesis
3.2. The equilibrium-point hypothesis: Single-muscle control
3.3. The equilibrium-point hypothesis: Single-joint control
3.4. Sources of misunderstanding: The alpha-model
3.5. Missing pieces of the mosaic
Chapter 4: Motor programming
4.1. Engrams and the generalized motor program
4.2. Control with patterns of muscle activation
4.3. Internal models
4.4. Missing pieces of the mosaic
Chapter 5: The principle of abundance and the uncontrolled manifold hypothesis
5.1. The principle of abundance
5.2. The uncontrolled manifold hypothesis
5.2.1. Analysis in kinematic spaces
5.2.2. Analysis in kinetic spaces
5.2.3. Analysis in muscle activation spaces
5.3. Dealing with non-linear systems
5.4. Motor equivalence
5.5. Missing pieces of the mosaic
Part II: Current Understanding
Chapter 6: Synergies
6.1. Bernstein’s understanding of synergies and its development
6.2. Intra-muscle and multi-muscle synergies
6.3. Synergies in kinematic and kinetic spaces
6.4. Synergies in spaces of control variables
6.5. Possible neurophysiological mechanisms
6.6. Missing pieces of the mosaic
Chapter 7: Control with spatial referent coordinates
7.1. Referent coordinate (RC) as generalization of lambda
7.2. Hierarchical control with referent coordinates
7.3. Synergies in spaces of referent coordinates: Analysis of mechanics
7.4. Synergies in spaces of referent coordinates: Analysis of muscle activations
7.5. Synergies stabilizing referent coordinates
7.6. Missing pieces of the mosaic
Chapter 8: Anticipatory control of action
8.1. Anticipatory postural adjustments
8.2. Early postural adjustments
8.3. Grip adjustments to planned actions
8.4. Anticipatory synergy adjustments
8.5. Distinguishing APAs from ASAs
8.6. Missing pieces of the mosaic
Chapter 9: Stability, agility, and optimality
9.1. Definitions and metrics
9.2. Optimization in human movements
9.3. Inverse optimization
9.4. Optimality-stability trade-off
9.5. Agility-stability trade-off
9.6. Missing pieces of the mosaic
Chapter 10: Brain circuitry
10.1. What variables are encoded by brain signals?
10.2. What is encoded by neuronal populations?
10.3. Relations between brain structures and functions
10.4. The role of spinal circuitry
10.5 Effects of dominance
10.6. Missing pieces of the mosaic
Part III: Effectors and Behaviors
Chapter 11: Synergic control of a muscle
11.1. Steps and challenges in analysis of motor unit-based synergies
11.2. Agonist-antagonist interactions at the motor unit level
11.3. Stabilization of reflex-induced force changes
11.4. Spinal vs. supraspinal synergies
11.5. Missing pieces of the mosaic
Chapter 12: The hand
12.1. Muscle organization of the hand
12.2. Indices of finger interaction
12.3. Finger modes
12.4. Grip force
12.5. Prehension synergies
12.6. Principle of superposition
12.7. Force- and moment-stabilizing synergies
12.8. Missing pieces of the mosaic
Chapter 13: Reaching
13.1. Spinal coordination of multi-joint movements
13.2. Control of reaching with spatial referent coordinates
13.3. Multi-joint synergies
13.4. Equifinality of reaching movements and its violations
13.5. Reach-to-grasp
13.6. Reaching with the dominant and non-dominant arms
13.7. Missing pieces of the mosaic
Chapter 14: Posture and whole-body actions
14.1. Postural sway and its components
14.2. Posture-stabilizing mechanisms
14.3. Whole-body voluntary movements
14.4. Whole-body synergies
14.5. Locomotion and central pattern generators
14.6. Missing pieces of the mosaic
Chapter 15: Kinesthetic perception
15.1. Ambiguity of sensory information
15.2. Perception of muscle length and force
15.3. Stability of percepts: The iso-perceptual manifold
15.4. Vibration-induced illusions
15.5. Interpreting impossible sensory signals
15.6. Missing pieces of the mosaic
Part IV: Surprising Phenomena
Chapter 16: Drifts in action
16.1. Spontaneous force drifts
16.2. Drifts in neural control variables
16.3. Faster drifts triggered by quick force changes
16.4. Unintentional kinematic drifts
16.5. Drifts in whole-body tasks
16.6. Drifts in indices of finger interaction
16.7. Classification of movements
16.8. Missing pieces of the mosaic
Chapter 17: Efference copy
17.1. Von Holst’s concept of efference copy
17.2. Efference copy as a referent coordinate
17.3. Is efference copy a copy of efference?
17.4. Perception and production of force
17.5. Muscle vibration and stability of percepts
17.6. The place for sense of effort
17.7. Missing pieces of the mosaic
Chapter 18: Equifinality and motor equivalence
18.1. Examples of equifinality and motor equivalence
18.2. Equifinality and the equilibrium-point hypothesis
18.3. Violations of equifinality in different spaces
18.4. Motor equivalence and the uncontrolled manifold hypothesis
18.5. Motor equivalence as a promising clinical index
18.6. Missing pieces of the mosaic
Chapter 19: Muscle coactivation
19.1. Surprising behavior of antagonist muscles
19.2. Features of the coactivation command
19.3. Does negative coactivation exist?
19.4. Changes in the C-command and their (mis)perception
19.5. Consequences of increased coactivation
19.6. Missing pieces of the puzzle
Part V: Improvements and Impairments
Chapter 20: Improvement in motor performance
20.1. Bernstein’s three stages
20.2. Can the way our brain controls movements be changed?
20.3. Changes in motor synergies with practice
20.4. Variability vs. stereotypy
20.5. Developmental changes
20.6. Motor rehabilitation: From magic to theory-based approaches
20.7. Missing pieces of the puzzle
Chapter 21. Decline in motor performance
21.1. Fatigue: Peripheral and central effects
21.2. Changes in synergies under fatigue
21.3. Aging: Effects on muscles, neurons, and performance
21.4. Changes in synergies with age.
21.5. Adaptive and maladaptive changes
21.6. Missing pieces of the puzzle
Chapter 22: Motor disorders in neurological patients
22.1. Large-fiber peripheral neuropathy
22.2. Spinal cord injury and spasticity
22.3. Parkinson’s disease
22.4. Other subcortical disorders
22.5. Stroke
22.6. Missing pieces of the puzzle
Part VI: Methodology
Chapter 23: Types of studies and hypothesis testing
23.1. Types of studies
23.2. Is a hypothesis worth testing?
23.3. Can a hypothesis account for the existing knowledge?
23.4. Can a hypothesis be used to make new testable predictions?
23.5. Exploration and development of a hypothesis
23.6. Missing pieces of the puzzle
Chapter 24: Measuring hidden variables
24.1. Measuring “biomechanical” variables
24.2. Measuring lambda
24.3. Measuring lambda in clinical studies
24.4. Missing pieces of the puzzle
Chapter 25: Writing papers
25.1. Inviting co-authors and selecting a journal
25.2. Introduction
25.3. Methods
25.4. Results
25.5. Tables and Figures
25.6. Discussion
25.7. Responding to reviews
25.8. Rejection: What to do next?
References