For both rodents and non-human primates, maternal separation (MS) is often used to mimic childhood adversity in humans, which can lead to brain dysfunction and, as results, behavioral abnormalities. People who suffer from psychiatric disorders due to childhood adversity usually have lived a normal social life prior to the onset of the diseases. But the effects of MS on rodents could be reversed by later experience.

In order to identify whether the adverse effects of MS are reversible by later normal social living in rhesus monkeys, a research group headed by Dr. HU Xintian and Prof. MA Yuanye in Institute of Biophysics, Chinese Academy of Sciences conducted a long-term study and established an animal model for human early adversity in rhesus monkeys.

The results showed that MS led to dysfunction of HPA axis, which helps manage stress, and resulted in abnormal behaviors in these rhesus monkeys. Furthermore, the normal social life appeared not to have obliterated the imprints of MS, suggesting that the effects of MS are long-lasting. Thus, compared to rodent models of MS, the maternal separated rhesus monkeys are a more suitable animal model to study the effects of childhood adverse experiences among people and to investigate the development of psychiatric disorders induced by exposure to childhood adversity.

The study work has been recently published on PNAS online and links to: http://www.pnas.org/content/108/34/14312.full. Afterwards, a variety of media rapidly reported the work, including the BBC news (links to http://www.bbc.co.uk/news/science-environment-14562120).