Memory Makes the Brain: The Biological Machinery that Uses Experiences to Shape Individual Brains

Description

The development of the young brain after birth and the emergence of cognitive capacities, mind, and individuality rest on the maturation of a dense net of synaptic connections between neurons. Memory Makes the Brain describes the dramatic, competitive elimination of surplus synapses that occur in the young, maturing brain in a process called synaptic pruning that was discovered by pediatric neurologist Peter Huttenlocher in the 1970's at the University of Chicago. Explaining similarities between developmental pruning and learning processes in the adult brain, neurobiologist Christian Hansel offers a unique perspective on brain adaptation and plasticity throughout lifetime, at times weaving in personal accounts and memories. The cellular plasticity machinery that enables learning is known to be affected in brain developmental disorders such as autism. Memory Makes the Brain explains how both maturation and adult synaptic plasticity are deregulated in autism, and how we begin to trace back autism-typical behavioral abnormalities to such synaptopathies. Contents Acknowledgments Introduction 1. Peter Huttenlocher and the Discovery of Synaptic Pruning References 2. Why Postnatal Brain Plasticity Is Needed: Limitations of Genetic Blueprints References 3. What Goes Up Must Come Down: Synaptic Potentiation and Depression Calcium Influx as a Trigger Signal for Long-term Potentiation (and Depression) Downstream of Calcium Transients: Biochemical Pathways Regulating AMPA Receptor Trafficking References 4. Across Time: Shared Synaptic Plasticity Machinery in the Developing and the Adult Brain Pruning in the Visual Cortex Following Molecular Deprivation The Molecular Machinery of Synaptic Depression at a Cerebellar Synapse Climbing Fiber Pruning in the Developing Cerebellum Synapse Elimination and LTD at the NMJ Temporal Continuity Between LTD-like Depression and Synapse Elimination Termination of the Critical Period A Role in Autism References 5. Synaptopathies: Synaptic Dysfunction in Autism Genetic and Environmental Factors Contribute to Autism Cell Physiological Signatures of the Autistic Brain Autism Phenotypes that may Result from LTD Deregulation References 6. The Study of Autism-Resembling Behaviors in Mouse Models Modeling Human Behaviors in Laboratory Animals Three-chamber Test for Social Approach Ultrasonic Vocalization in Mice Repetitive Behaviors: Marble Burying and Self-grooming Anxiety: Tests for the Occupation of Open Versus Protected Spaces Nociception: Hot Plate Test and Tail Flick Test Motor Performance and Motor Learning The Importance of Access to Underlying Brain Circuits Animal Models Other than Mice Autism from a Synaptic Perspective References 7. The Memory Engram References 8. Limitations: The Non-Synaptic Plasticity Component References 9. Ensemble Sequences, Associative Plasticity and the Learning of Causal Relationships Intrinsic Plasticity and Learned Feature Generalization Effect Robustness and Duration Synaptic and Intrinsic Mechanisms Control the Probability of Engram Activation and Engram Sequences Intrinsic Contributions Synaptic Contributions Language Impairment and Cerebellar Dysfunction in Autism References 10. Plasticity and the Shaping of Individual Brains Plasticity, Circuit Learning and the Origin of Individuality Individuality and Self-awareness Arising from Experience References Index