Washington, Dec 28 (IANS) Exposure to babies can trigger maternal instincts among women, says a study.
Researchers from Tufts University Cummings School of Veterinary Medicine exposed virgin or nulliparous rats to foster pups daily until they began to exhibit maternal behaviour.

The behaviour included crouching over the young, grouping them, or retrieving them back to the nest. The study also showed that such female rats have an increased number of new neurons (nerve cells).

Researchers Miyako Furuta and Robert Bridges from Tufts conducted the study.

Previous research has found that exposure to young can stimulate maternal behaviour not only in rats, but also in mice, hamsters, monkeys, and even humans.

Increased creation of new neurons or neurogenesis, has also been shown during pregnancy and lactation in rodents and associated with maternal behaviour.

However, studies analysing neurogenesis in virgin animals exhibiting maternal behaviour had not been done.

The area of the brain that was the focus of the present study was the region involved in the production of cells that affect odour recognition and possibly recognition of young.

Bridges and Furuta found increased numbers of new neurons in this zone in adult, nulliparous rats that behaved maternally, compared with numbers in subjects that either were not exposed to young or exposed to young, but did not behave maternally.

What stimulates increased new neuron production in such virgin mothers is not known.

One possibility is that the hormone prolactin, which stimulates both the onset of maternal behaviour as well as production of neurons during pregnancy, may play a role in the production of new neurons, says a Tufts release.

A second possibility is that stimulation received from the young themselves may, in fact, play a crucial role in stimulating maternal neuron production.

“These are the questions we hope to answer,” says Bridges.

These findings were published in Brain Research Bulletin.