Neuropsicologia

Annu. Rev. Psychol. 1998. 49:43–64 Copyright © 1998 by Annual Reviews Inc. All rights reserved

BRAIN PLASTICITY AND BEHAVIOR
Bryan Kolb and Ian Q. Whishaw
Department of Psychology, University of Lethbridge, Lethbridge, Alberta, T1K 3M4 Canada; e-mail: kolb@HG.ULETH.CA
KEY WORDS: dendrite arborization, environmental enrichment, cortex, neuropsychology, experience

ABSTRACT
Brainplasticity refers to the brain’s ability to change structure and function. Experience is a major stimulant of brain plasticity in animal species as diverse as insects and humans. It is now clear that experience produces multiple, dissociable changes in the brain including increases in dendritic length, increases (or decreases) in spine density, synapse formation, increased glial activity, and alteredmetabolic activity. These anatomical changes are correlated with behavioral differences between subjects with and without the changes. Experience-dependent changes in neurons are affected by various factors including aging, gonadal hormones, trophic factors, stress, and brain pathology. We discuss the important role that changes in dendritic arborization play in brain plasticity and behavior, and weconsider these changes in the context of changing intrinsic circuitry of the cortex in processes such as learning.

CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . METHODS OFSTUDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis of Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis of the Brain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXPERIENCE AND THE CHANGINGBRAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Environmental Enrichment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Training in Specific Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Olfactory Experience in Rodents . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . Plasticity in the Avian Brain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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The Invertebrate Nervous System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . Dendrites and Behavior in Humans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MODULATION OF EXPERIENCE-DEPENDENT CHANGE . . . . . . . . . . . . . . . . . . . . . . Aging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sex Hormones. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neurotrophins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Injury . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INTRODUCTION
One of the key principles of behavioral neuroscience is that experience can modify brain structure long after brain development is complete. Indeed, it is generally...