Distinct Patterns of Brain Activity Mediate Perceptual and Motor and Autonomic Responses to Noxious Stimuli

experimental set-up showing that the scientists randomized the time between laser pulses and how strong the pulses were. Perception (how it felt), motor (reaction time), and autonomic (skin conductance) responses were measured after laser pulses.

Experimental design from Tiemann et al.

Today I learned: a group of scientists figured out that distinct brain responses are involved in mediating our response to pain (noxious stimulus) via motor (movement), perceptual (feeling), and autonomic (unconscious body reactions like signal conducting) responses. To figure out this stimulus-brain-outcome relationship they measured motor (reaction times), perceptual (pain rating 0-100), autonomic (skin conductance), and brain (brain waves) responses to a series of random laser pulses (varied in both the time between pulses and the intensity of the pulses). As expected, more intense laser pulses caused the participants to have a faster reaction time, a higher pain rating, and stronger skin conductance measurements. But what was really interesting about this study was that they found that of the four brain waves they measured, not all were responsible for every response. Rather, each brain wave was involved in mediating either only one or two of the responses to the laser pulses. And contrary to what most people would expect, the earliest brain waves were not involved in the perception response, which means that you don’t need to consciously perceive the painful stimulus in order to have a motor or autonomic response.

Reference: Tiemann, Laura, et al. “Distinct Patterns of Brain Activity Mediate Perceptual and Motor and Autonomic Responses to Noxious Stimuli.” Nature Communications, vol. 9, no. 1, 2018, doi:10.1038/s41467-018-06875-x.