Science reveals why the brain connects to the opposite side of the body

Human brain is strange, and so are the mysteries related to it. As per a recent report published in the journal of News Medical Lifesciences, it was mentioned that the left side of the human brain controls the opposite side of your body, and the right side of your brain controls the left side of your body. Interestingly, this arrangement is not so obvious; this is because each side of your brain is linked to the side of your body, and the wiring would be simpler and less likely to fail. This crossed wiring is found even in almost all animals, even in simple nematode worms. A new analysis mentioned in the journal of Frontiers in Neuroanatomy by researchers Daniel Wang and Martin Wessendorf gives an idea of how this strange setup may have evolved.A question scientists have asked for centuriesThere’s no denying that this debate and curiosity around it is pretty old. After many centuries scientists still do not have a final answer. This new hypothesis builds on anatomical studies and offers a simple explanation. As per the study, Wessendorf, a neuroscientist and associate professor emeritus at the University of Minnesota, studies how the brainstem controls the cord. He and his co-author suggest that this crossed wiring started with a specific ancient visual system. In animals each eye sends sight information to the opposite side of the brain's optic tectum, a part of the brain that processes sight. The researchers think that once this side visual map was in place early in evolution, other systems used it as a template. As the study explains, adding touch, hearing, and movement circuits around an existing opposite-side map likely needed fewer changes than building a new same-side arrangement from scratch. In words, evolution chose the easier route, reusing an existing crossed wiring instead of creating a new one.Not the same as left-right brain specializationWell, it is important to explain that crossed wiring is not the same as right brain specialization. The researchers clarify that this phenomenon is different from lateralization, the type of left-right specialization that explains handedness. Crossed wiring is broad and symmetrical; each hemisphere of the brain simply connects to the side of the body, not to a special task.Why this arrangement might actually be smarterOther researchers propose that crossed wiring may actually lower wiring mistakes during brain growth. Theoretical work in the journal The Naked Scientists mentioned that a developing brain may be more likely to wire when one hemisphere controls the opposite side of the body instead of the same side. This might be because it gives a reliable developmental map for the nervous system. In fact, the researchers admit that this idea is still a hypothesis based on comparing anatomy across animals not on direct experiments or fossils. The next step, the paper says, is to test whether anatomical studies and fossil records back this optic tectum idea.Why this still mattersEven if a final answer is not yet reached, this research gives a part of the puzzle. It suggests that one of the brain's strangest design choices may not be random. The echo of an ancient visual map that appeared hundreds of millions of years ago and never got changed.Get the latest movie news, reviews, and celebrity updates. Download the TOI App.