Abstract
Recent functional brain connectivity studies have contributed to our understanding of the neurocircuitry supporting pain perception. However, evoked-pain connectivity studies have employed cutaneous and/or brief stimuli, which induce sensations that differ appreciably from the clinical pain experience. Sustained myofascial pain evoked by pressure cuff affords an excellent opportunity to evaluate functional connectivity change to more clinically relevant sustained deep-tissue pain. Connectivity in specific networks known to be modulated by evoked pain (sensorimotor, salience, dorsal attention, frontoparietal control, and default mode networks: SMN, SLN, DAN, FCN, and DMN) was evaluated with functional-connectivity magnetic resonance imaging, both at rest and during a sustained (6-minute) pain state in healthy adults. We found that pain was stable, with no significant changes of subjects’ pain ratings over the stimulation period. Sustained pain reduced connectivity between the SMN and the contralateral leg primary sensorimotor (S1/M1) representation. Such SMN–S1/M1 connectivity decreases were also accompanied by and correlated with increased SLN–S1/M1 connectivity, suggesting recruitment of activated S1/M1 from SMN to SLN. Sustained pain also increased DAN connectivity to pain processing regions such as mid-cingulate cortex, posterior insula, and putamen. Moreover, greater connectivity during pain between contralateral S1/M1 and posterior insula, thalamus, putamen, and amygdala was associated with lower cuff pressures needed to reach the targeted pain sensation. These results demonstrate that sustained pain disrupts resting S1/M1 connectivity by shifting it to a network known to process stimulus salience. Furthermore, increased connectivity between S1/M1 and both sensory and affective processing areas may be an important contribution to interindividual differences in pain sensitivity.
Highlights
Neuroimaging analyses of functional brain connectivity have significantly impacted our understanding of brain function and the networks supporting perception of pain
Our study found that sustained pain led to a distinct shift in functional brain connectivity
When the brain is at rest, different S1/M1 cortical representation regions are in direct communication, leading to robust inter-connectivity within the so-called sensorimotor network [5]
Summary
Neuroimaging analyses of functional brain connectivity have significantly impacted our understanding of brain function and the networks supporting perception of pain. Functional connectivity has not yet been evaluated during sustained experimental pain most likely because continuous administration of many experimentally applied pain stimuli (e.g. heat) risks permanent tissue damage It is unknown if the altered resting connectivity noted in chronic pain patients differs from sustained pain state connectivity in healthy adults. It is unknown how functional connectivity during sustained pain relates to pain sensitivity, which is known to vary widely between individuals [54]. We hypothesized that inter-subject differences in cuff pain sensitivity could be predicted by variability in functional brain connectivity present in the sustained pain state
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
