In social fish like cichlids, status is everything. High-status males are territorial and colorful – they defend territories and reproduce with females. Low-status males, which are less colorful and can’t maintain territories, are also not reproductively active. Scientists trying to understand how this social stress might affect the fish dissected cichlid brains and found that low-status fish had generally higher levels of oxidative stress, which is linked to poorer mental and neurological health in humans. Meanwhile, high-status fish had generally higher levels of antioxidants, which protect against oxidative stress damage.

Researchers from the lab of Richard Simerly have uncovered the first example of activity-dependent development of hypothalamic neural circuitry. The work also suggests a novel role for the hunger hormone leptin in specifying the development of neural circuits involved in autonomic regulation and food intake.