The reasons for our left or right-handedness
Unlike hitherto assumed, the cause is not to be found in the brain.
It is not the brain that determines if people are right or left-handed, but the spinal cord. This has been inferred from the research results compiled by a team headed by private lecturer Dr Sebastian Ocklenburg, Judith Schmitz, and Prof Dr H. C. Onur Güntürkün. Together with colleagues from the Netherlands and from South Africa, the biopsychologists at Ruhr-Universität Bochum have demonstrated that gene activity in the spinal cord is asymmetrical already in the womb. A preference for the left or the right hand might be traced back to that asymmetry.
“These results fundamentally change our understanding of the cause of hemispheric asymmetries,” conclude the authors. The team report about their study in the journal “eLife”.
Preference in the womb
To date, it had been assumed that differences in gene activity of the right and left hemisphere might be responsible for a person’s handedness. A preference for moving the left or right hand develops in the womb from the eighth week of pregnancy, according to ultrasound scans carried out in the 1980s. From the 13th week of pregnancy, unborn children prefer to suck either their right or their left thumb.
Read more at Ruhr University Bochum
Image Credits: Marquard via Ruhr University Bochum