Body and Brain: A Trophic Theory of Neural Connections
by Dale Purves
Harvard University Press, 1988 Paper: 978-0-674-07716-4 | Cloth: 978-0-674-07715-7 Library of Congress Classification QP363.P87 1988 Dewey Decimal Classification 599.0188
ABOUT THIS BOOK | TOC
ABOUT THIS BOOK
The major goal of developmental neurobiology is to understand how the nervous system is put together. A central theme that has emerged from research in this field over the last several decades is the crucial role of trophic interactions in neural assembly, and indeed throughout an animal's life. Trophic—which means nutritive—refers to long-term interdependencies between nerve cells and the cells they innervate.
The theory of trophic effects presented in this book offers an explanation of how the vertebrate nervous system is related to—and regulated by—the body it serves. The theory rationalizes the nervous system's accommodation, throughout life, to the changing size and form of the body it tenants, indicating the way connections between nerve cells change in response to stimuli as diverse as growth, injury, experience, and natural selection.
Dale Purves, a leading neurobiologist best known for his work on the formation and maintenance of synaptic connections, presents this theory within the historical setting of earlier ideas about neural organization—from Weiss's theory of functional reorganization to the chemoaffinity theory championed by Sperry. In addition to illuminating eighty years of work on trophic interactions, this book asks its own compelling questions: Are trophic interactions characteristic of all animals or only of those with complex nervous systems? Are trophic interactions related to learning? What does the trophic theory of neural connections imply about the currently fashionable view that the nervous system operates according to Darwinian principles?
Purves lays the theoretical foundation for practical exploration of trophic interactions as they apply to neural connections, a pursuit that will help us understand how our own nervous systems generate change. The ideas in this book not only enrich neurobiology but also convey the profound relevance of neuroscience to other fields of life science.
TABLE OF CONTENTS
Contents
1
Introduction
Definitions
Historical Background
The Trophic Theory as an Organizing Principle
2
Effects of Animal Size and Form on the Organization of the Nervous System
Somatic Representation
Influence of Size on the Nervous System
Influence of Form on the Nervous System
Significance of Neural Adjustment to Changes in Size and Form
3
Coordination of Neuronal Number and Target Size
Neuronal Populations in Small, Simple Animals
Neuronal Populations in Large, Complex Animals
Mechanisms That Coordinate Neuronal Number and Target Size
Some Provisos
Regulation of Neuronal Populations by Their Targets in Ontogeny and Phylogeny
4
Neuronal Form and Its Consequences
Diversity of Neuronal Form
Neuronal Form in Small, Simple Animals
Neuronal Form in Large, Complex Animals
Neuronal Form in Phylogeny
Functional Consequences of Neuronal Geometry
5
Regulation of Developing Neural Connections
Formation of Neuronal Connections in Vertebrates
Synaptic Rearrangement in the Peripheral Nervous System
Competitive Nature of Synaptic Rearrangement
Synaptic Rearrangement in the Central Nervous System
Purposes of Synaptic Rearrangement
6
Regulation of Neural Connections in Maturity
Target-Dependent Neuronal Survival
Experimentally Induced Changes of Connectivity
Normal Remodeling of Axonal and Dendritic Branches
Uncertainties about Plasticity of Central Connections
Reasons for Ongoing Trophic Interactions
7
A Molecular Basis for Trophic Interactions in Vertebrates
NGF as a Regulator of Neuron Survival
NGF as a Regulator of Neuronal Processes
Effects of NGF on Axons, Dendrites, and Synapses
A General Scheme for the Action of Trophic Molecules
Other Target-Derived Trophic Molecules
Uncertainties about the Biology of NGF
The Significance of Trophic Molecules
8
Effects of Neural Activity on Target Cells and Their Trophic Properties
Effects of Neural Activity on Target Cells
Influence of Neural Activity on Retrograde Trophic Signaling
Influence of Neural Activity on the Arrangement of Competing Inputs
Influence of Neural Activity on Convergent Innervation
A Model of Activity-Dependent Trophic Support
Some Complications
The Significance of Activity-Dependent Modulation of Neural Connections
9
Implications of the Trophic Theory of Neural Connections
Implications for Different Taxa
Implications for Learning and Memory
Implications for Regressive Theories of Neural Connectivity
Body and Brain: A Trophic Theory of Neural Connections
by Dale Purves
Harvard University Press, 1988 Paper: 978-0-674-07716-4 Cloth: 978-0-674-07715-7
The major goal of developmental neurobiology is to understand how the nervous system is put together. A central theme that has emerged from research in this field over the last several decades is the crucial role of trophic interactions in neural assembly, and indeed throughout an animal's life. Trophic—which means nutritive—refers to long-term interdependencies between nerve cells and the cells they innervate.
The theory of trophic effects presented in this book offers an explanation of how the vertebrate nervous system is related to—and regulated by—the body it serves. The theory rationalizes the nervous system's accommodation, throughout life, to the changing size and form of the body it tenants, indicating the way connections between nerve cells change in response to stimuli as diverse as growth, injury, experience, and natural selection.
Dale Purves, a leading neurobiologist best known for his work on the formation and maintenance of synaptic connections, presents this theory within the historical setting of earlier ideas about neural organization—from Weiss's theory of functional reorganization to the chemoaffinity theory championed by Sperry. In addition to illuminating eighty years of work on trophic interactions, this book asks its own compelling questions: Are trophic interactions characteristic of all animals or only of those with complex nervous systems? Are trophic interactions related to learning? What does the trophic theory of neural connections imply about the currently fashionable view that the nervous system operates according to Darwinian principles?
Purves lays the theoretical foundation for practical exploration of trophic interactions as they apply to neural connections, a pursuit that will help us understand how our own nervous systems generate change. The ideas in this book not only enrich neurobiology but also convey the profound relevance of neuroscience to other fields of life science.
TABLE OF CONTENTS
Contents
1
Introduction
Definitions
Historical Background
The Trophic Theory as an Organizing Principle
2
Effects of Animal Size and Form on the Organization of the Nervous System
Somatic Representation
Influence of Size on the Nervous System
Influence of Form on the Nervous System
Significance of Neural Adjustment to Changes in Size and Form
3
Coordination of Neuronal Number and Target Size
Neuronal Populations in Small, Simple Animals
Neuronal Populations in Large, Complex Animals
Mechanisms That Coordinate Neuronal Number and Target Size
Some Provisos
Regulation of Neuronal Populations by Their Targets in Ontogeny and Phylogeny
4
Neuronal Form and Its Consequences
Diversity of Neuronal Form
Neuronal Form in Small, Simple Animals
Neuronal Form in Large, Complex Animals
Neuronal Form in Phylogeny
Functional Consequences of Neuronal Geometry
5
Regulation of Developing Neural Connections
Formation of Neuronal Connections in Vertebrates
Synaptic Rearrangement in the Peripheral Nervous System
Competitive Nature of Synaptic Rearrangement
Synaptic Rearrangement in the Central Nervous System
Purposes of Synaptic Rearrangement
6
Regulation of Neural Connections in Maturity
Target-Dependent Neuronal Survival
Experimentally Induced Changes of Connectivity
Normal Remodeling of Axonal and Dendritic Branches
Uncertainties about Plasticity of Central Connections
Reasons for Ongoing Trophic Interactions
7
A Molecular Basis for Trophic Interactions in Vertebrates
NGF as a Regulator of Neuron Survival
NGF as a Regulator of Neuronal Processes
Effects of NGF on Axons, Dendrites, and Synapses
A General Scheme for the Action of Trophic Molecules
Other Target-Derived Trophic Molecules
Uncertainties about the Biology of NGF
The Significance of Trophic Molecules
8
Effects of Neural Activity on Target Cells and Their Trophic Properties
Effects of Neural Activity on Target Cells
Influence of Neural Activity on Retrograde Trophic Signaling
Influence of Neural Activity on the Arrangement of Competing Inputs
Influence of Neural Activity on Convergent Innervation
A Model of Activity-Dependent Trophic Support
Some Complications
The Significance of Activity-Dependent Modulation of Neural Connections
9
Implications of the Trophic Theory of Neural Connections
Implications for Different Taxa
Implications for Learning and Memory
Implications for Regressive Theories of Neural Connectivity