The brain of Kim Peek, the model for the 1988 film Rain Man, was severely abnormal with, among other things, no corpus callosum.
Some savants, however, are people who started life with what appear to have been normal brain structures and abilities, but who suddenly became savants after an injury. These, such as the two people identified here, are called acquired savants:
- Orlando Serrell is one such acquired savant. He possessed no special skills until, when he was 10 years old, he was struck by a baseball on the left side of his head. After an initial period of headaches, he suddenly demonstrated the ability to perform complex calendar calculations and nearly perfect memory for every day since the accident.
- Derek Amato acquired musical savant skill after a head injury incurred when diving into a shallow pool. A few days after the head injury, he sat down at a friend's piano and was suddenly able to play and compose music, despite never having played before.
Although not in the same category as these acquired savants, extraordinary memory recall elicited by brain stimulation during neurosurgery (such as done by Canadian neurosurgeon Wilder Penfield on epileptics) or hypnosis suggests that some untapped memory or skill repository may exist in everyone that remains latent unless released following some unusual stimulus.
How people would have such latent skills and why they'd have them but never use them is a deep mystery in neuroscience.