Amazing stuff! The power of hormones!
From the abstract of the perspective:
"Pregnancy requires extensive physiological remodeling to provide the energy required for gestating a fetus and delivering and nurturing a newborn. Successful mothering requires an additional finely tuned behavioral repertoire. In most mammals, this starts with retrieval to a nest, grooming, and nursing. Estradiol and progesterone, the same pregnancy hormones that remodel the body, also program the brain for mothering, but precisely how this occurs has been opaque. ... report the identification of galanin neurons in the medial preoptic area (MPOA) as the cellular target of steroid programming in mice. Estradiol and progesterone changed the activity of galanin neurons such that the sensitivity to stimuli emanating from the pups (e.g., odors and vocalizations) was much stronger. New synapses were also formed on the galanin neurons. These remarkably specific changes were sufficient to promote mothering behavior."
From the editor's summary and abstract:
"Motherhood leads to pronounced behavioral changes in many species, such as altered feeding routines and increased aggressivity. How does pregnancy prepare females for such future behavioral needs? ... discovered that the hormonal milieu of pregnancy remodels a distinct population of hypothalamic neurons in mice ... that mediates the onset of parental behavior before giving birth. Sensing of estradiol and progesterone by galanin-expressing neurons in the medial preoptic area is necessary for this behavioral change. Therefore, hormone-mediated neuronal modifications lead to an increased selectivity for pup stimuli, thus anticipating future parenting behaviors. ...
Abstract
Abstract
During pregnancy, physiological adaptations prepare the female body for the challenges of motherhood. Becoming a parent also requires behavioral adaptations. Such adaptations can occur as early as during pregnancy, but how pregnancy hormones remodel parenting circuits to instruct preparatory behavioral changes remains unknown. We found that action of estradiol and progesterone on galanin (Gal)–expressing neurons in the mouse medial preoptic area (MPOA) is critical for pregnancy-induced parental behavior. Whereas estradiol silences MPOAGal neurons and paradoxically increases their excitability, progesterone permanently rewires this circuit node by promoting dendritic spine formation and recruitment of excitatory synaptic inputs. This MPOAGal-specific neural remodeling sparsens population activity in vivo and results in persistently stronger, more selective responses to pup stimuli. Pregnancy hormones thus remodel parenting circuits in anticipation of future behavioral need."
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