Like human fathers, male marmosets help raise their young. Neuroimaging studies show that stimuli related to one's own child activate the anterior paracingulate and orbitofrontal areas of the prefrontal cortex (PFC). The PFC shows structural plasticity in adulthood and contains receptors for several neuropeptides implicated in parental behavior, such as vasopressin, oxytocin and prolactin. Kozorovitskiy et al now report in Nature Neuroscience that first-time and experienced marmoset fathers have enhanced density of dendritic spines on pyramidal neurons in prefrontal cortex as compared to non-fathers. In parallel, the abundance of vasopressin V1a receptors and the proportion of V1a receptor–labeled dendritic spines increase. How this links to function and behavior is not known, and it would be interesting to see if similar changes are seen in the brains of nonparental caregivers (since marmosets breed cooperatively).
Left) Marmoset father carrying infants. Right) Pyramidal neuron of a marmoset father, with close-up views of apical (a) and basal (b) dendrites.