Reprogramming the maternal brain

Over summer 2008/2009 Sarah Madill participated in a 10 week Summer Studentship supported from a scholarship through the Otago School of Medical Sciences. She recounts her experiences.

I became a member of the Centre for Neuroendocrinology under the guidance of my supervisor Dr Caroline Larsen.

The aim of this summer research project was to provide insight into how levels of the pregnancy hormone, prolactin, can ‘reprogram' the brain to become a ‘maternal brain'.

Prolactin has been implicated as a key hormone for the establishment of maternal care.

Dr Larsen, working with Prof Dave Grattan in the Department of Anatomy and Structural Biology, had previously shown that exposing non-pregnant mice to pups increases prolactin levels in the blood and enhances maternal behaviour.

Moreover, this enhanced maternal behaviour is retained weeks and months later.

We refer to this long-term change in behaviour as "maternal memory".

The aim of this study was to test whether pup-induced prolactin secretion is the signal that initiates this "maternal memory".

The transient pup-induced increase in prolactin was sufficient to activate prolactin receptors in brain regions crucial for maternal behaviour, and thus, might be involved in maternal memory.

Blocking prolactin secretion had inconclusive results, however, possibly due to a rebound rise in prolactin twenty hours later causing incomplete blockade.

Aspects of this work will need to be repeated in light of this observation.

Alterations in prolactin levels during pregnancy can dramatically impair maternal behaviour postpartum.

Postnatal mood disorders such as anxiety which may affect the way the mother interacts with her baby.

This can have detrimental effects on the mother and her offspring and may have long lasting effects on infant development.  It is hoped that these results will assist researchers in the on-going hunt for understanding how differences in hormone secretion during pregnancy can affect parental care.

I had a great summer working in the Centre for Neuroendocrinology testing my ability as a scientist, learning new techniques and meeting new people.