Abstract
The importance of hormones in mediating a behavioural transition in mammals from a virgin or non-parenting state to parental state was established around 50 years ago. Extensive research has since revealed a highly conserved neural circuit that underlies parental behaviour both between sexes and between mammalian species. Within this circuit, hormonal action in the medial preoptic area of the hypothalamus (MPOA) has been shown to be key in timing the onset of parental behaviour with the birth of offspring. However, the mechanism underlying how hormones act in the MPOA to facilitate this change in behaviour has been unclear. Technical advances in neuroscience, including single cell sequencing, novel transgenic approaches, calcium imaging, and optogenetics, have recently been harnessed to reveal new insights into maternal behaviour. This review aims to highlight how the use of these tools has shaped our understanding about which aspects of maternal behaviour are regulated by specific hormone activity within the MPOA, how hormone-sensitive MPOA neurons integrate within the wider neural circuit that governs maternal behaviour, and how maternal hormones drive changes in MPOA neuronal function during different reproductive states. Finally, we review our current understanding of hormonal modulation of MPOA-mediated paternal behaviour in males.The importance of hormones in mediating a behavioural transition in mammals from a virgin or non-parenting state to parental state was established around 50 years ago. Extensive research has since revealed a highly conserved neural circuit that underlies parental behaviour both between sexes and between mammalian species. Within this circuit, hormonal action in the medial preoptic area of the hypothalamus (MPOA) has been shown to be key in timing the onset of parental behaviour with the birth of offspring. However, the mechanism underlying how hormones act in the MPOA to facilitate this change in behaviour has been unclear. Technical advances in neuroscience, including single cell sequencing, novel transgenic approaches, calcium imaging, and optogenetics, have recently been harnessed to reveal new insights into maternal behaviour. This review aims to highlight how the use of these tools has shaped our understanding about which aspects of maternal behaviour are regulated by specific hormone activity within the MPOA, how hormone-sensitive MPOA neurons integrate within the wider neural circuit that governs maternal behaviour, and how maternal hormones drive changes in MPOA neuronal function during different reproductive states. Finally, we review our current understanding of hormonal modulation of MPOA-mediated paternal behaviour in males.