The Brain in Motion: From Microcircuits to Global Brain Function

An evolutionary perspective-from lampreys to humans-on how the forebrain coordinates movement while the networks in the brainstem and spinal cord handle the execution. An evolutionary perspective-from lampreys to humans-on how the forebrain coordinates movement while the networks in the brainstem and spinal cord handle the execution. All living creatures interact with their environment- even the most basic have a set of innate motor circuits they rely on to feed, locomote, fight, and flee. In The Brain in Motion, Sten Grillner describes the evolution of the motor repertoire of vertebrates, from protovertebrates to primates. With breadth and depth, Grillner explores how the brain uses the different microcircuits in the brainstem and spinal cord, coordinating them through commands from the forebrain. He also considers the normal function of the brain as a platform for understanding clinical conditions such as stroke, Parkinson s and Huntington s diseases, and spinal cord injury. Grillner also explains in The Brain in Motion how the remarkable finding that the lamprey forebrain has all the components of the mammalian one has radically changed scientists' views on the evolutionary origin of the vertebrate forebrain. We now know that the basic organization evolved 560 rather than 300 million years ago, as was previously thought. The forebrain, says Grillner, is like an orchestra conductor, while the microcircuits, with their reaching, grasping, posture, locomotion, and numerous other patterns of behavior, correspond to the members of the orchestra. The conductor determines when each will be called into action. Providing an elegantly integrated perspective, The Brain in Motion is essential reading for anybody that works professionally with movement control and function and dysfunction, whether in basic research, clinically, or in the training of motor skills.

Table of Contents:
Preface ix
1 THE VERTEBRATE MOTOR REPERTOIRE AND THE EVOLUTION
OF THE BRAIN 1
1.1 Introduction 1
1.2 Vertebrate Motor Behavior from Lamprey to Humans: Overview in an
Evolutionary Perspective 3
1.3 The Basic Building Blocks of Behavior: Motor Programs and Their
Selection—Overview 21
1.4 The Blueprint of the Vertebrate Motor System Is 500 Million Years Old 27
2 EXECUTION OF MOVEMENT: A PALETTE OF CPGS AND MOTOR
CENTERS FROM MIDBRAIN TO SPINAL CORD 39
2.1 Introduction 39
2.2 CPG Networks Producing Locomotor, Respiratory, and Chewing Movements
and Related Behaviors 40
2.3 A Brainstem Center for Coordination of Reaching and Grasping Movements
in the Lateral Reticular Medulla 66
2.4 The PAG Channels Commands from the Hypothalamus and Amygdala 71
2.5 Integration of Innate Motor Programs in Daily Life: Skilled Aspects of the
Control of Motion 78
2.6 Conclusion 80con
3 THE VERTEBRATE SOLUTION FOR ACTION IN THE
EGOCENTRIC SPACE: MULTISENSORY INTEGRATION IN
THE TECTUM/SUPERIOR COLLICULUS 81
3.1 Introduction 81
3.2 Multisensory Representation of the Surrounding Space in the Tectum/SC 82
3.3 Tectum/SC Control of Eye, Orienting, and Evasive Movements 89
3.4 Conclusion 96
4 THE ROLES OF THE BASAL GANGLIA: FOR INITIATION OF
MOVEMENT AND MOTOR LEARNING 97
4.1 Overview: The Relation between the Cortex and the Basal Ganglia 97
4.2 Basal Ganglia: Organization 101
4.3 Synaptic Interaction within the Striatum 117
4.4 Integrated Function of the Basal Ganglia 127
4.5 Dysfunction of the Basal Ganglia: Parkinson’s and Huntington’s Diseases
and Other Conditions 143
4.6 The Contribution of the Basal Ganglia to the Selection of Action and the
Control of Movement Amplitude 153
4.7 The Organization of the Basal Ganglia Is Conserved from Lampreys
to Primates 160
5 THE ROLE OF THE CORTEX IN THE CONTROL OF MOVEMENT 165
5.1 Introduction 165
5.2 Somatosensory and Visuomotor Coordination Critical in the Preparatory
Phase and the Transition between Diferent Commands in a
Motor Sequence 168
5.3 The Motor Areas in the Frontal Lobe of Primates and Other Vertebrates 175
5.4 Neocortical Organization at the Cellular Level and the Interaction between
the Frontal Motor Areas, Striatum, and Downstream Motor Targets 189
5.5 Motor Capacity after Lesions to the Neocortex, Including the
Motor Cortex 197
5.6 Cortical Control of Robotic Arms via the Brain-Machine Interface after
Spinal Cord Injury 200
5.7 Concluding Remarks: The Neocortex and the Control of Movement 201
6 THE CEREBELLUM: CONTRIBUTES TO THE PERFECTION
OF COORDINATION 203
6.1 Introduction 203
6.2 The Cerebellar Circuitry 203
6.3 Spinal Cord Interaction with the Cerebellum: Locomotion and
Other Movements 210
6.4 The Cerebellum and the Vestibulo-Ocular and Optokinetic Reflexes:
Calibration of Motor Action 215
6.5 Parallel Fiber Synapses onto Purkinje Cells: Active and Silent Synapses—
Plasticity 218
6.6 The Cerebellum’s Role for Learning to Associate Two Related but
Independent Processes: Conditioned Reflexes 219
6.7 Modeling and Simulation of the Cerebellar Circuitry 219
6.8 Concluding Remarks: The Overall Role of the Cerebellum 220
7 COMMENTS ON WHAT WE HAVE LEARNED AND
THE CHALLENGES AHEAD 223
7.1 “To Move or Not to Move,” a Question Answered by the Basal Ganglia
in Close Interaction with the Cortex 224
7.2 The Major Organizational Building Blocks of Motion 226
7.3 The Role of the Cerebellum: The Perfection of Coordination 226
7.4 Some Challenges Ahead 227
References 231
Index 261

About the Author :
Sten Grillner is Distinguished Professor at the Karolinska Institute in Sweden and previous head of the Nobel Institute for Neurophysiology.