Cortical Asymmetry - Left Brain, Right Brain

Professor Daniel Geschwind explains that cortical asymmetry refers to differences between the right and left side of the brain. This relates to gene expression.

Cortical asymmetry is a concept that is related to human cognitive function. In other words of all the species, our brains are the most asymmetric. The left side is the most different from the right in our brain, even relative to our closest relative, the chimpanzee. And this asymmetry is very, very important. It is because of the asymmetry that we likely have language and many other higher cognitive specializations. So part of our research and other people’s research has been to identify genes that control asymmetry so that we can understand how a human becomes a human and how it’s different from a chimp. So far, we in collaboration with a laboratory at Harvard, Chris Walsh’s lab, identified a number of genes that were expressed asymmetrically and that was the first evidence that in the human fetal brain, there actually is what we call transcriptional asymmetry, that is different genes are expressed on one side than the other, or earlier on the right side than on the left side. This is very exciting. This however does not mean we know which genes cause the asymmetry yet, and that research is still ongoing. But what we’ve seen is the first molecular readout of the structural and functional asymmetry that is present in the human brain.