These fMRI images reflect what's happening in the brain when people perform simple imitation tasks with the left or right hand. (Doesn't the bottom-left image look a bit like two hands held together in the shape of a bowl, as if trying to cup a few precious sips of water?) So far, the researchers have analyzed about a dozen subjects, all right-handers. I stopped into their lab two weeks ago and was the first lefty in the experiment. No data yet, but the idea is to see how activation might differ for lefties, one hypothesis being that it will be more symmetrical. The group is based at Harvard and Tom Zeffiro was extremely generous with his time. A southpaw as well, Zeffiro is equally perplexed by the mystery of left-handedness. Paraphrasing something he told me: If mostly left-hemispheric lateralization for language and a mostly right-handed population are unrelated phenomena, that could be one of the greatest coincidences in all of neuroscience.
Meanwhile, this BBC story describes a gene that may play a part in handedness, or in increasing the likelihood of left-handedness. I'm not sure what to make of it just yet, but one thing is certain: the British infatuation with the subject of handedness never ceases to amaze me.