The Primitive Reflexes

Watch as this newborn displays a strong ‘grasp-reflex’ literally seconds after being pulled out of the womb. This is one example of the primitive reflexes that a healthy infant displays. This reflex can be tested by stroking the palm of a baby’s hand, which causes the baby to close his or her fingers in a grasp. The grasp reflex lasts until about five to six months of age.

In pediatrics, medical students are taught to assess the Moro-reflex (the baby’s ability to abduct and extend arms when startled, and then draw together), the Rooting reflex (ability to move its head towards one side if cheek or mouth is stroked – nipple seeking), the Sucking reflex (sucking response when roof of mouth touched), the Plantar reflex (dorsiflexion of large toe and fanning of other toes with plantar stimulation), and the Galant reflex (stroking along one side of the spine while newborn is in ventral position – face down – this causes lateral flexion of lower body towards stimulated side) on physical exam. These ‘primitive’ reflexes are inhibited by a mature and developing frontal lobe of the brain but they may reemerge in adults following frontal-lobe lesions, which can be due to loss of inhibition of these reflexes.