MadSci Network: Neuroscience |
Hi! Your question about brain differences between right and left handed people is very interesting. Apparently, about 80% of humans prefer using the right hand. A number of attempts have been made to examine whether the left motor cortex (which controls the right hand) is anatomically larger than the right cortex. Most studies have been inconclusive. However, a recent study examining the FUNCTION of the cortex, rather than just the anatomy, has confirmed that the motor cortex contralateral to the dominant hand does indeed show more functional activity than the other side (see P Dassonville, et al., "Functional activation in motor cortex reflects the direction and degree of handedness" in the journal Proceedings of the National Academy of Sciences vol. 95, p. 11499, 1998). Another study has shown that a portion of the corpus callosum might be larger in right handed persons, but the overall dimensions of the entire corpus callosum do not show these changes (KD Hopper, "The relationship of age,gender, handedness, and sidedness to the size of the corpus callosum" Acad. Radiol. vol. 1, p. 243, 1994--you can access abstracts of these papers by going to www.pubmed.gov). It seems likely that training yourself to use both hands may eventually result in long lasting functional changes in the motor cortex (called plasticity), which would probably be a good thing and would improve your motor abilities. It is less likely that this would result in a change in overall IQ.
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