Background: One of the barriers to studying the behavioral and emotional effects of pain using functional Magnetic Resonance Imaging (fMRI) is the absence of a commercially available, MRI-compatible, pressure-based algometer to elicit pain. The present study sought to address this barrier through creation and validation of a novel MRI-safe apparatus capable of delivering incremental, measurable amounts of pressure inside a scanning bore.
New method: We introduced an MR-safe device used to administer pressure-based pain. To test against a commercially available, MRI-incompatible algometer (AlgoMed), 199 participants reported their pain tolerance for both devices. A second experiment tested the validity of pressure-based pain in an MRI environment by comparing brain activation with established neural networks for pain. 10 participants performed an identical procedure to test for pain tolerance while being scanned in a 7T MRI scanner.
Results: Results support the validity and reliability of our novel device. In Study 1, pain tolerance with this device was strongly correlated with pain tolerance as measured by a commercially available algometer (r=0.78). In Study 2, this device yielded BOLD activation within the insula (BA 13) and anterior cingulate gyrus (BA 24); as pressure increased, activation in these areas parametrically increased.
Comparison with existing method: These findings correspond to other studies using thermal, electrical, or mechanical pain applications. Behavioral and functional data demonstrate that this new device is a valid method of administering pressure-related pain in MRI environments.
Conclusions: Our novel MRI-safe device is a valid instrument to measure and administer pressure-based pain.
Keywords: Algometer; Anterior cingulate cortex; Insula; MRI-safe pressure-based pain tolerance device; Pain.
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