For more information, see Francois et al., http://www.cell.com/neuron/fulltext/S0896-6273(17)30010-7.
Mood, expectations, stress, hunger, and sleep quality all play a role in setting our sensitivity to pain. This video summarizes the findings by Francois et al. and shows how brainstem neurons control the release of endogenous opioids to set pain thresholds.
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