14 DAY TRIAL // Those cute traits of an infant's face, such as large head and forehead, big eyes and bulging cheeks, trigger instinctive parental and protective responses in us. This has been known for long, but a new research revealed the anatomic base of this behavior. The study led by Morten Kringelbach and Alan Stein from the University of Oxford and published in the journal "PLoS ONE" has found the parental behavior to be triggered by the medial orbitofrontal cortex, turned on in 0.14 seconds when seeing (unfamiliar) infant faces, but not adult faces.
The team at Aston University, UK, employed magnetoencephalography (MEG), a technique that delivers detailed images (in a resolution of mm) of whole brain activity at a time scale of milliseconds.
The subjects had to press a button as soon as the color of a small red cross changed. From time to time, adult and infant faces appeared on the monitor for 300 ms. This way, the researchers detected in the brains of normal adults an increased activity in the medial orbitofrontal cortex when viewing infant faces, but not adult ones. This wave of activity appeared about 0.14 seconds after seeing an infant face. Such a fast response is rather unconscious and instinctive.
The medial orbitofrontal cortex is a crucial area of the emotional brain, connected to reward-related stimuli. It appears that the medial orbitofrontal cortex triggers the emotional tagging of infant faces that makes us to bond with our children.
The team also connected depression to the neighboring subgenual cingulate cortex, strongly connected with the medial orbitofrontal cortex. It appears that activity changes in the medial orbitofrontal cortex connected to depression could impact parental responsiveness. Postnatal depression installs in over 13% of the mothers and these women have difficulties in reacting to infant stimuli. This new knowledge could lead to early identification of women at risk.