Can we distract ourselves away from pain? Previous research indicates that cognition, the act of thinking may reduce pain. This is possible because pain and cognition compete for shared brain resources. So why can’t we always block pain with cognition? In the present study, the research team shows that too much or too little information processing makes pain stronger or cognition weaker at blocking pain.
goal
Zoha Deldar and her team aimed to test how the amount of information processed during a cognitive task affects pain. Examples of cognitive tasks are those that require thinking for example, selecting an option among different alternatives or staying focused on a certain task. The research team also examined the communication between the brain and the spinal cord during the tasks.
methodology
For this project, 38 healthy volunteers performed a cognitive task (n-back) for which the amount of information was different depending on group allocation (2-back or 3-back). Participants had to discriminate between bleu and yellow squares with more or less information to remember (0-back and 2-back or 0-back and 3-back). In the 0-back condition, participants discriminated the color of the current stimulus immediately after its presentation. In the 2-back and 3-back conditions, they reported the color of the stimulus presented 2 or 3 trials before, respectively. Pain and a withdrawal reflex were evoked by electrical stimulation at the ankle. The withdrawal reflex reflects spinal cord activity and how the brain blocks pain messages sent to the brain. Participants had to rate their pain after each condition between 0-100.
main findings
Pain was decreased by cognition, and more so when it involved more information to process 2/3-back vs 0-back. This effect partly depended on the communication between the brain and spinal cord. It was also observed that too much information (3-back) was not more beneficial at blocking pain, suggesting that there is a limit to this ability.
take home message
Cognition can decrease pain through communication between the brain and spinal cord. These findings may guide the development of non-pharmacological cognitive-based interventions for pain management.
