What if you could find your way home, but couldn't recognize anyone when you got there?
Reporting in the July issue of Nature Genetics, scientists at the Center for Behavioral Neuroscience at the Yerkes Primate Center have discovered in mouse studies that the oxytocin gene is necessary for forming social memories -- allowing you to recognize an individual you've seen before.
The gene has no apparent influence on spatial or other types of memory. The study demonstrates that social memory has a neural basis distinct from other forms of memory, and someday could provide a therapeutic target for a variety of psychiatric illnesses.
The study's author, Jim Winslow, Ph.D., associate research professor of psychobiology at Yerkes, says the ability to recognize those we have met before is the first step in the process of developing an affiliative relationship. "Without this fundamental ability, even your own mother would remain a stranger," he says. It is thought that such a defect could play a role in autism and schizophrenia, which are characterized by a sense of social disconnection and isolation.
The gene in question codes for the brain hormone oxytocin (OT), which is present in all mammals, including humans. This neuropeptide has long been associated in many species with a range of social behaviors, including parental care (such as nursing and parturition), pair bonding and mate-guarding. In humans, oxytocin peaks during ejaculation. To date, there have been no studies in humans on the role of OT in pair bonding, though studies in monkeys show that increased transmission of the peptide does increase social interaction.
Dr. Winslow's team made its discovery with the help of a transgenic or "knockout" mouse, engineered to lack the gene for oxytocin. In the study, knockout mice were compared with normal mice in tests for social and non-social memory.