The brains of left-handed and right-handed people are organized differently, with the two groups using opposite sides of the brain for functions such as language and spatial perception. Left- and right-handers also use different parts of the brain to focus on the whole versus the parts of a visual stimulus, reports a paper in the March issue of Nature Neuroscience.
People often have to choose between focusing on either the details ('the trees') or the global aspect ('the forest') of a picture. The authors used transcranial magnetic stimulation (TMS, a technique that transiently disrupts brain activity) to show that right and left-handers use opposite sides of the brain to do such a task. They applied TMS over either the left or the right parietal lobe at the back of the brain while volunteers concentrated on the details of a visual stimulus.
Disrupting activity over the left parietal lobe affected right-handers more, while left-handers were more affected when activity was disrupted over the same area on the right. These results show that left- and right-handers might use their brains differently even for relatively low-level processing.
Carmel Mevorach (University of Birmingham, UK)
Tel: +44 121 414 8550
Also available online.
(C) Nature Neuroscience press release.
Message posted by: Trevor M. D'Souza