Scientists shed light on how brains turn pain up or down

Pain perception is essential for survival, but how much something hurts can sometimes be amplified or suppressed: for example, soldiers who sustain an injury in battle often recall not feeling anything at the time.

A new study published in Cell Reports on Tuesday honed in on the brain circuitry responsible for upgrading or downgrading these pain signals, likening the mechanism to how a home thermostat controls room temperature. Yarimar Carrasquillo, the paper’s senior author and a scientist for the National Center for Complementary and Integrative Health (NCCIH), said the region responsible was the central amygdala, which according to her work appeared to play a dual role.

Studying mice, Carrasquillo and her colleagues found that the activity in neurons that express protein kinase C-delta amplified pain, while neurons that express somatostatin inhibited the chain of activity in the nerves required to communicate pain. The central amygdala isn’t completely responsible for pain itself: if it were removed entirely, then “the ‘ouch’ of things, or the protective pain, would remain intact,” said Carrasquillo.