A hypothalamic node for the cyclical control of female sexual rejection

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Reproductive Biology

Background:

• Behavioral flexibility, crucial for social interactions, allows switching between accepting and rejecting sexual advances based on reproductive state.
• The ventrolateral ventromedial hypothalamus (VMHvl) is known to regulate sexual acceptance, but the neural basis of sexual rejection remains unclear.

Purpose of the Study:

• To identify the neural mechanisms underlying female sexual rejection behavior.
• To investigate the role of progesterone receptor-expressing neurons in the anterior VMHvl (aVMHvl^PR+) in regulating sexual rejection.

Main Methods:

• In vivo recordings to monitor neural activity during sexual rejection and acceptance.
• Slice electrophysiology to analyze synaptic input balance in aVMHvl^PR+ neurons.
• Optogenetic manipulation (activation and inhibition) of aVMHvl^PR+ neurons to assess their effect on sexual behavior.

Main Results:

• aVMHvl^PR+ neurons are active during sexual rejection and inactive during sexual acceptance.
• These neurons exhibit a reduced excitatory-to-inhibitory synaptic input balance in receptive females.
• Activating aVMHvl^PR+ neurons increases rejection in receptive females, while inhibiting them reduces rejection in non-receptive females.

Conclusions:

• Progesterone receptor-expressing neurons in the anterior VMHvl (aVMHvl^PR+) are critical regulators of female sexual rejection.
• These neurons act as a neural substrate controlling mating behavior, potentially serving as a barrier to mating when fertilization is not possible.