Transformations of neural representations in a social behaviour network

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Social Behavior

Background:

• Mating and aggression are innate social behaviors regulated by subcortical circuits, including the extended amygdala and hypothalamus.
• The bed nucleus of the stria terminalis (BNSTpr) integrates sex-specific olfactory cues and projects to hypothalamic nuclei controlling mating (MPOA) and aggression (VMHvl).
• Previous work suggested male BNSTpr neurons are crucial for mounting and attack, potentially identifying conspecific sex.

Purpose of the Study:

• To characterize neural representations within the BNSTpr and their functional transformations in the hypothalamus during social behaviors.
• To investigate the role of BNSTpr neurons in sex identification and the transition between appetitive and consummatory phases of male social behaviors.

Main Methods:

• Calcium imaging of male BNSTprEsr1 neurons during social behaviors.
• Chemogenetic silencing of BNSTprEsr1 neurons while simultaneously imaging MPOAEsr1 or VMHvlEsr1 neurons in behaving animals.

Main Results:

• Identified distinct populations of female- versus male-tuned neurons in BNSTpr, with female-tuned neurons being more numerous.
• Observed an inversion of the sex-tuning bias in VMHvl from male-dominant to female-dominant upon BNSTpr silencing.
• Found that BNSTpr silencing attenuated the switch from sniff- to mount-selective neurons during mating in the MPOA.
• Demonstrated that BNSTprEsr1 neurons are not essential for conspecific sex identification.

Conclusions:

• BNSTprEsr1 neurons play a critical role in modulating sex- and behavior-specific neural representations within the hypothalamus.
• These neurons are essential for controlling the transition from appetitive to consummatory phases of male social behaviors.
• The findings challenge the notion that BNSTpr neurons are primarily involved in conspecific sex identification.