Experience-dependent plasticity in an innate social behavior is mediated by hypothalamic LTP

Area of Science:

• Neuroscience
• Behavioral Biology
• Endocrinology

Background:

• Innate behaviors are hardwired but can be modified by experience.
• Aggression training, involving repeated winning, increases aggressiveness.
• The neural mechanisms and brain regions underlying this plasticity are not fully understood.

Purpose of the Study:

• To investigate the neural basis of experience-dependent plasticity in aggression.
• To identify specific synaptic changes associated with aggression training.
• To explore the role of hormones in mediating individual differences in plasticity.

Main Methods:

• Investigated synaptic plasticity using long-term potentiation (LTP) and long-term depression (LTD) in the posteromedial amygdalohippocampal area (AHiPM) to ventromedial hypothalamus (VMHvl) circuit.
• Utilized optogenetics to manipulate synaptic plasticity in vivo.
• Measured aggression behaviors and testosterone levels in mice.

Main Results:

• Aggression training induced LTP at AHiPM→VMHvl Esr1+ synapses.
• Optogenetic induction of LTP facilitated, while LTD diminished, aggression training effects.
• Individual differences in aggression training response correlated with testosterone levels and LTP.
• Exogenous testosterone restored plasticity in non-responsive mice.

Conclusions:

• LTP at AHiPM→VMHvl synapses mediates experience-dependent plasticity in innate aggression.
• Testosterone plays a crucial role in enabling this neural and behavioral plasticity.
• Identified a hormone-dependent basis for individual differences in plasticity within a genetically identical population.