Wang et al. have determined the social hierarchy within groups of mice by using multiple behavioral tests and find that the social hierarchical status of an individual correlates with the synaptic strength in medial prefrontal cortical neurons. Furthermore, the hierarchical status of mice can be changed from dominant to subordinate, or vice versa, by manipulating the strength of synapses in the medial prefrontal cortex. Here is the abstract, followed by a figure from the review by Maroteaux and Mamell:
Dominance hierarchy has a profound impact on animals’ survival, health, and reproductive success, but its neural circuit mechanism is virtually unknown. We found that dominance ranking in mice is transitive, relatively stable, and highly correlates among multiple behavior measures. Recording from layer V pyramidal neurons of the medial prefrontal cortex (mPFC) showed higher strength of excitatory synaptic inputs in mice with higher ranking, as compared with their subordinate cage mates. Furthermore, molecular manipulations that resulted in an increase and decrease in the synaptic efficacy in dorsal mPFC neurons caused an upward and downward movement in the social rank, respectively. These results provide direct evidence for mPFC’s involvement in social hierarchy and suggest that social rank is plastic and can be tuned by altering synaptic strength in mPFC pyramidal cells.
Illustration (click to enlarge) - Synapses and rank - Excitatory synaptic drive onto cortical pyramidal neurons in the mouse brain is stronger in dominant individuals than subordinates. Modulating synaptic strength by increasing or decreasing AMPA receptor–mediated transmission switches the initial social ranking.