Professor George Paxinos’ opinion piece about love: Sydney Morning Herald

This Valentines Day, as on all that have gone before it, lovers will exchange cards with hearts on them. But all the Valentines Day stationery and emojis depicting hearts instead of brains to signify love perpetuate a fallacy from long, long ago.

It began with the Egyptians of the 3rd millennium BC. They considered the heart to be the seat of thought, memory, will and emotion. Before burial they heedlessly discarded the brain and for millennia, pharaohs were delivered brainless to the afterlife.

The problem with the brain is that, unlike the heart, it does not flutter when lovers kiss. So without special investigation, it is impossible to infer that the brain creates the mind and emotions. Alcmaeon (circa 520-450 BC; possibly a student of Pythagoras) is credited with the discovery of the relationship between the mind and the brain. It is thought that Alcmaeon was led to his astonishing conclusion by his observation that all senses are connected to the brain through channel-like structures, which today we call nerves.

Hippocrates (460-370BC) is believed to have been influenced by Alcmaeon’s concept in expressing an amazingly modern view that can still be heard in neuroscience departments today: “Men ought to know that from the brain, and from the brain only, arise our pleasures, joys, laughter and jests, as well as our sorrows, pain, griefs and tears. Through it, in particular, we think, see, hear, and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant.”

After Hippocrates, things went downhill for the brain for a while. Plato (429-347 BC) confused matters by attributing the emotional soul to the heart.

The worst blowcame from Aristotle (384-322 BC), who was Plato’s student. He attributed to the brain the pedestrian function of cooling the blood, but placed the seat of the soul in the heart. Then Galen (130-201 AD), physician to the Roman emperor Marcus Aurelius, proposed that the psychic pneuma (mind) resided in the ventricles of the brain and, via the nerves, was in receipt of sensory information and controlled the muscles.

Modern science has not only rejected the heart as the seat of love, but is making progress in identifying specific structure in the brain involved in the erotic, cognitive, emotional and behavioural components of love.

In the first major work on this, Andreas Bartels and Semir Zeki, of University College London, in 2000 studied the brain activity of subjects who were deeply in love via functional MRI, while the subjects viewed pictures of their partners (compared to viewing friends of similar age and sex). The caudate/putamen — the area receiving dopamine and involved with reward, the medial insula and the anterior cingulate were activated, while the amygdala – the area involved in fear — was deactivated.

Cardiac transplant surgeons inadvertently delivered the coup de grace to the cardiocentric theory of love. Heart transplant recipients do not fall in love with the wives of the dead donors (cinema not withstanding). This proves that wherever else love may reside, clearly it is not in the heart.

The idea that love comes from the brain rather than the heart is now as well established as the idea of anthropogenic global warming. That is, beyond doubt.

It is time, therefore, that the fallacious cardiocentric theory of love be abandoned and lovers on Valentines Day exchange cartoons of the organ really responsible for their emotion – the brain – the shape of which is every bit as beautiful as the heart.

George Paxinos AO is NHMRC Senior Principal Research Fellow with Neuroscience Research Australia.