Israeli researchers have discovered that the brain chemical oxytocin, often referred to as the “love hormone,” plays a crucial role in how young animals cope with parental separation and form emotional bonds, providing new insights into early social development.
The study, led by Prof. Ofer Yizhar at the Weizmann Institute of Science and published in Science, introduced a noninvasive technique to silence specific brain cells in mouse pups without disturbing their natural behavior. The method, based on optogenetics, uses a light-sensitive protein to temporarily switch off nerve cells deep in the brain, allowing scientists to study oxytocin’s impact in real time.
Researchers found that when separated from their mothers, mouse pups with active oxytocin systems adapted more quickly and cried less, whereas those with silenced oxytocin systems continued to emit distress calls until their mothers returned. The hormone also shaped behavior after reunion. Pups with functioning oxytocin systems produced distinctive vocalizations signaling a need for closeness, followed by calmer sounds once comfort was restored.
Yizhar said the technique provides scientists with a way to examine the brain without disrupting the pups’ natural behavior, offering a valuable tool for studying how the nervous system develops. He added that because oxytocin’s impact is shaped by social context, the method allows researchers to track its effects during carefully chosen situations.
The team also uncovered early differences between the sexes. Female pups showed greater sensitivity to oxytocin activity than males, suggesting that divergence in social and emotional development begins earlier than previously thought.
The findings shed light on attachment theory, which posits that a child’s bond with a caregiver influences their future relationships. They may also help explain how disruptions in oxytocin pathways could contribute to developmental conditions such as autism.