Thursday, 13 August 2009

Why Humans Talk And Chimps Don't

It's a fertile time, at the moment, for interesting comparative functional neuroscience! Here an article reports on recent work on Broca's Area, by Chet Sherwood and team. They sectioned and examined Broca's Area from a dozen chimps and discovered that there is no left-right asymmetry in terms of number of neurons and that there were a lot of individual differences in the size, location and symmetry of Broca's Area, rather than a pan-species norm - as exists in humans. Neither was the handedness of the chimps in any way related to symmetry of Broca's (Broca's Area in chimps has been related to the use of hand gestures and tool use). Furthermore, they notice that, while the human brain in total is some 3.6 times larger than the chimp brain, Broca's Area in the human is 6 times larger than in the chimp. It has ballooned in the human lineage.

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