Brain Function and Plasticity

Early experience has a lasting impact on our ability to perceive the world. When it is missing -- because of temporary blindness or deafness -- there are seemingly permanent deficits in sensory processing. Comparable deprivation in adulthood has no adverse effects. Similarly, unlike adult stroke, brain damage from a stroke early in life can be largely mitigated by wholesale remapping of the brain. These findings illustrate the well-established principle that the brain is initially plastic and that its connections are tuned by early experience to match the environment. When the experience is missing during a critical period early in life, it appears to be too late to change the brain. However, recent evidence indicates that there is considerable residual plasticity in the adult brain. That evidence will be illustrated by examples from three diverse fields. The first example is that the vision of adults can be improved by training or playing action videogames, even when vision was damaged by abnormal early visual experience (e.g., lazy eye, cataract). The second example is that a variety of interventions lead to successful recovery from adult stroke. The third example is that physical exercise can modify the plasticity of the adult brain and even mitigate the typical cognitive degeneration with aging. In each case, the speakers will consider the mechanisms underlying the plasticity and whether they are best viewed as a reinstatement of childhood plasticity or a different process.