Seminars in Motor Control

Mark L. Latash is a Distinguished Professor of Kinesiology and Director of the Motor Control Laboratory at the Pennsylvania State University. His research interests are focused on the control and coordination of human voluntary movements, movement disorders in neurological disorders, and effects of rehabilitation. He served as the Founding Editor of the journal "Motor Control" (1996-2007) and as President of the International Society of Motor Control (2001-2005).

• 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 activation4.3. 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 equivalence5.5. 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 mechanisms6.6. Missing pieces of the mosaic Chapter 7: Control with spatial referent coordinates 7.1. Referent coordinate (RC) as generalization of lambda7.2. Hierarchical control with referent coordinates 7.3. Synergies in spaces of referent coordinates: Analysis of mechanics7.4. 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 actions8.4. Anticipatory synergy adjustments 8.5. Distinguishing APAs from ASAs8.6. 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-off9.6. 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 circuitry10.5 Effects of dominance10.6. 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 synergies11.5. Missing pieces of the mosaic Chapter 12: The hand 12.1. Muscle organization of the hand12.2. Indices of finger interaction12.3. Finger modes12.4. Grip force12.5. Prehension synergies 12.6. Principle of superposition 12.7. Force- and moment-stabilizing synergies12.8. 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 synergies13.4. Equifinality of reaching movements and its violations13.5. Reach-to-grasp13.6. Reaching with the dominant and non-dominant arms13.7. Missing pieces of the mosaic Chapter 14: Posture and whole-body actions 14.1. Postural sway and its components 14.2. Posture-stabilizing mechanisms14.3. Whole-body voluntary movements14.4. Whole-body synergies 14.5. Locomotion and central pattern generators14.6. Missing pieces of the mosaic Chapter 15: Kinesthetic perception 15.1. Ambiguity of sensory information15.2. Perception of muscle length and force15.3. 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 variables16.3. Faster drifts triggered by quick force changes 16.4. Unintentional kinematic drifts16.5. Drifts in whole-body tasks 16.6. Drifts in indices of finger interaction 16.7. Classification of movements16.8. 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 force17.5. Muscle vibration and stability of percepts17.6. The place for sense of effort17.7. Missing pieces of the mosaic Chapter 18: Equifinality and motor equivalence18.1. 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 index18.6. 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 performance21.1. Fatigue: Peripheral and central effects 21.2. Changes in synergies under fatigue21.3. Aging: Effects on muscles, neurons, and performance21.4. 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 neuropathy22.2. 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 studies23.2. 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 Figures25.6. Discussion 25.7. Responding to reviews 25.8. Rejection: What to do next? References