Maternal behaviors are essential for the survival of the young. Previous studies implicated the medial preoptic area (MPOA) as an important region for maternal behaviors, but details of the maternal circuit remain incompletely understood. Here we identify estrogen receptor alpha (Esr1)-expressing cells in the MPOA as key mediators of pup approach and retrieval. Reversible inactivation of MPOA cells impairs those behaviors, whereas optogenetic activation induces immediate pup retrieval. In vivo recordings demonstrate preferential activation of MPOA cells during maternal behaviors and changes in MPOA cell responses across reproductive states. Furthermore, channelrhodopsin-assisted circuit mapping reveals a strong inhibitory projection from MPOA cells to ventral tegmental area (VTA) non-dopaminergic cells. Pathway-specific manipulations reveal that this projection is essential for driving pup approach and retrieval and that VTA dopaminergic cells are reliably activated during those behaviors. Altogether, this study provides new insight into the neural circuit that generates maternal behaviors.

Beatty JA, Song SC, Wilson CJ. Cell-type-specific resonances shape the responses of striatal neurons to synaptic input. J Neurophysiol 113: 688 -700, 2015. First published November 19, 2014 doi:10.1152/jn.00827.2014.-Neurons respond to synaptic inputs in cell-type-specific ways. Each neuron type may thus respond uniquely to shared patterns of synaptic input. We applied statistically identical barrages of artificial synaptic inputs to four striatal cell types to assess differences in their responses to a realistic input pattern. Each interneuron type fired in phase with a specific input-frequency component. The fast-spiking interneuron fired in relation to the gamma-band (and higher) frequencies, the low-threshold spike interneuron to the beta-band frequencies, and the cholinergic neurons to the delta-band frequencies. Low-threshold spiking and cholinergic interneurons showed input impedance resonances at frequencies matching their spiking resonances. Fast-spiking interneurons showed resonance of input impedance but at lower than gamma frequencies. The spiny projection neuron's frequency preference did not have a fixed frequency but instead tracked its own firing rate. Spiny cells showed no input impedance resonance. Striatal interneurons are each tuned to a specific frequency band corresponding to the major frequency components of local field potentials. Their influence in the circuit may fluctuate along with the contribution of that frequency band to the input. In contrast, spiny neurons may tune to any of the frequency bands by a change in firing rate.

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Sexual and aggressive behaviors are fundamental to animals’ survival and reproduction. The medial preoptic nucleus (MPN) and ventrolateral part of ventromedial hypothalamus (VMHvl) are essential regions for male sexual and aggressive behaviors, respectively. While key inhibitory inputs to VMHvl and MPN are identified, the extra-hypothalamic excitatory inputs essential for the social behaviors remain elusive. Here we identify estrogen receptor alpha (Esr1) expressing cells in posterior amygdala (PA) as a main source of excitatory inputs to hypothalamus and key mediators for mating and fighting in male mice. We find two largely distinct PA subpopulations that differ in connectivity, gene expression, in vivo responses and social behavior relevance. MPN projecting PA Esr1+ cells are activated during mating and necessary and sufficient for male sexual behaviors, while VMHvl projecting PA Esr1+ are excited during inter-male aggression and promote attacks. These findings place PA as a key node in both male aggression and reproduction circuits.

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