Brain plasticity is examined through the work of Dr. Michael Merzenich, a pioneer in the field; Dr. Skip Rizzo, who developed an immersive program to help servicemembers with PTSD; Dr. Christopher DeCharms, who helps patients reduce chronic pain with cognitive training; Dr. John Donoghue, who helps restore communication and mobility to people with tetraplegia or paralysis; and Dr. Peter Whitehouse, who created a program for senior citizens with mild cognitive impairment.