Gestation leads to a modification of brain circuits and behaviors such as nesting within the animal kingdom. The underlying biological, neural and hormonal mechanisms have been unknown until now. In a new study, the team led by Nicolas Renier (Inserm) at the Paris Brain Institute has discovered a novel role for hormone-sensitive neurons in the centre of the brain, which are necessary for maternal nesting behaviour in female mice. These results were published in the journal Neuron.
Nesting behaviors are often triggered before the arrival of newborns in parental species. Nest building in birds is perhaps the first example that comes to mind, but this behaviour is also present in all mammals, including humans, to reorganize their habitat before the birth of a baby. The mechanisms by which gestation in mammals will modify the brain circuits and behaviors of everyday life are still elusive. Do the pregnancy hormones play a role in this form of brain plasticity?
To answer these questions, Thomas Topilko, a graduate student in Nicolas Renier's team (Inserm), and his colleagues used the mouse as a model. When pregnant, the female mouse prepares a nest to protect its young from the cold and from predators.
Using a sophisticated technique, light-sheet microscopy, to map brain activity in three dimensions and on a micrometre scale, the researchers identified an unexpected region in the centre of the brain, the Edinger Westphal nucleus, as being involved in maternal preparatory nesting behaviour.
