For 400 years, mainstream medicine and science believed that brain anatomy was fixed. The common wisdom was that after childhood the brain changed only when it began the long process of decline; that when brain cells failed to develop properly, or were injured, or died, they could not be replaced. Nor could the brain ever alter its structure and find a new way to function if part of it was damaged... [This] theory decreed that people who were born with brain or mental limitations, or who sustained brain damage, would be limited...for life.
We now know that the brain changes its structure with each different activity it performs, and that if certain parts fail, other parts sometimes take over. This process, called neuroplasticity, has been the most significant learning about the brain since its basic anatomy was first mapped.
The Brain That Changes Itself is a fascinating must-read that chronicles stories of how this theory is impacting people once labeled retarded, those with learning disabilities, stroke victims, those with OCD, and others whose brains have failed them in traditional ways.
Order this book by Norman Doidge, MD here.
Source: Paraphrased and quoted from the book's preface.