The reasons for hemispheric dominance in the brain

The left and the right hemispheres specialise in different tasks. However, it has not yet been fully understood how one hemisphere assumes dominance over the other when it comes to controlling specific functions. Biopsychologists at Ruhr-Universität Bochum describe their latest findings.Dr. Qian Xiao and Professor Onur Güntürkün have demonstrated in pigeons that the dominance is caused by slight differences in temporal activity patterns in both hemispheres.

Novel research approach

The two hemispheres are connected via thick nerve fibre bundles, so-called commissures. "In the past, it had been assumed that the dominant hemisphere transmits inhibitory signals to the other hemisphere via the commissures, thus suppressing specific functions in that region," explains Onur Güntürkün. However, the interactions that take place between the two hemispheres are excitatory, as well as inhibitory. "This is why it has remained a mystery where, exactly, functional brain asymmetries stem from," says Güntürkün.

You could continue to read here.