'Tune In, Turn Off'

'There are a number of extraordinary cases in which people have suddenly developed savant-like abilities. One 9-year-old boy was transformed from an Ordinary school-kid to a Genius mechanic after part of his brain was destroyed by a bullet'

Many researchers argue that savant skills tend to be those which are associated more with the right hemisphere: music, identifying mathematical patterns and art, for example rather than skills that are predominantly associated with the left-hemisphere. Even the rare savants who have amazing word power, like Christopher, tend to be less interested in reading or the meaning of words, and more interested in skills like translation. Because of this, many have suggested that savant skills are produced by a dominant right hemisphere which has flourished in the absence of effective communication with or inhibition by the left.

Held Back

"Autistic people often show both structural and functional dysfunction in the left hemisphere," says Wisconsin psychiatrist Darold Treffert, author of a book called Extraordinary People: Understanding savant Syndrome, back in 1989. "Most cases are probably due to some prenatal brain development which prevents normal development of the cortex and left hemisphere," he says. "Testosterone, for example, is known to inhibit left-hemisphere development and in male foetuses temporary slowing of the left hemisphere may be a normal developmental stage. In autism that slowing may be protracted beyond normal, resulting in an overdeveloped right hemisphere and stunted growth on the left. This could explain why autism, and savant skills, are about six times more common in males than in females."

His theory seems to be supported by a number of extraordinary cases in which normal people have suddenly developed savant-like abilities after left-sided brain injuries. One 9-year-old boy, for example, was transformed from an ordinary school-kid to a genius mechanic after part of his left hemisphere was destroyed by a bullet. And Bruce Miller and co-workers at the University of California Los Angeles School of Medicine recently reported five patients who developed amazing drawing skills after dementia part of the left side of their brains (Neurology, vol 51, p978). "One of our patients had spent his life changing car stereos and had never shown any interest at all in art," says Miller. Then he developed dementia which destroyed neurons in the left frontotemporal cortex-an area which gives meaning to things-and suddenly he started to produce sensational images recalled from early childhood. It was as though the destruction of those brain cells took the brakes off some inate ability that had been suppressed all his life, and opened up access to an amazing personal memory store he never knew he had."

As yet it isn't clear whose interpretation of these cases is correct, if indeed anyone's is, but Snyder thinks there might be a way to test it. He is planning an experiment in which, he hopes, the unconscious savant will be unleashed at the flick of a switch. Magnetic pulses can interfere with normal brain activity. If you time and position the surge just right, it can temporarily turn off activity in a particular region. Snyder's plan is to "switch off" the conceptualising area. If his theory is correct, and if he can find the area, this should cause the normally pre-conscious savant skills to burst into consciousness. "I'm thinking of trying it on myself first," says Snyder. "If I start getting crystal clear pictures of my childhood or a sudden knowledge of prime numbers I'll really know I'm onto something."

Rita Carter
 
New Scientist 9 October 1999