Pain and executive functions: a unique relationship between Stroop task and experimentally induced pain.

There is a growing body of evidence that a higher level of cognitive inhibition is associated with lower experimental pain sensitivity. However, a systematic examination of the association between executive functions, which include not only inhibition but also updating and shifting, and experimental pain sensitivity is lacking. This study aimed to overcome this limitation by exploring the relationship between a range of executive functions and different measures of experimentally induced cold pain in healthy participants. In a group of 54 healthy participants (age 21-24 years), executive functions (EF) were investigated in a systematic manner following a well-established framework developed by Miyake and collaborators. The investigation included multiple tests of inhibition (Stroop, Stop-signal, and Left-right), updating (Keep-track, Letter-memory, and Spatial n-back), and set-shifting (Plus-minus, Number-letter, and Local-global). The cold pressor test was used to obtain measures of pain threshold (the first sensation of pain), sensitivity to pain (the moment when substantial pain was reported), and pain tolerance (the moment when pain became unbearable). Results showed no relationship between pain measures and measures of updating and shifting. All pain measures were related to Stroop interference inhibition score, but not to other two inhibition tasks. Further analyses confirmed the unique relationship between Stroop-type of inhibition and response to pain. We argue that there is a fundamental relationship between cognitive inhibition and pain experience, which relies on one's ability to suppress automatic processes.