The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Sessions of prolonged continuous theta burst stimulation or high-frequency 10 Hz stimulation to left dorsolateral prefrontal cortex for three days decreased pain sensitivity by modulation of the efficacy of conditioned pain modulation.
The 10 Hz repetitive transcranial magnetic stimulation (10 Hz-rTMS) to the left dorsolateral prefrontal cortex produces analgesia, probably by activating the pain modulation system. A newer rTMS paradigm, called theta burst stimulation (TBS), has been developed. Unlike 10 Hz-rTMS, prolonged continuous TBS (pcTBS) mimics endogenous theta rhythms, which can improve induction of synaptic long-term potentiation. ⋯ Based on pooled data from pcTBS and 10 Hz-rTMS, the increased PPTs correlated with increased efficacy of CPM at Day3 (P = .008), while no correlations were found at Day4 or with the intracortical excitability. PERSPECTIVE: Preliminary results of this comparative study did not show stronger pain sensitivity reduction by pcTBS compared with 10 Hz-rTMS to the L-DPFC. Both protocols maintained increased pain thresholds up to 24-hours after the last session, which were partially associated with modulation of CPM efficacy but not with the intracortical excitability changes.
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Using the EEG recordings of patients with endometriosis-related chronic pelvic pain, we have examined the effective connectivity within the cortical pain-related network during rest and during pain-related imagery. During rest, an altered connectivity was hypothesized between cortical somatosensory pain areas and regions involved in emotional and cognitive modulation of pain. During pain-related imagery, alterations in prefrontal-temporal connectivity were expected. ⋯ Results of this study open up new directions in chronic pain research aimed at exploring the beta band connectivity alterations. PERSPECTIVE: This study examined the pain system's dynamics in endometriosis patients with chronic pelvic pain during resting-state and pain-related mental imagery. The results could contribute to the development of new therapies using guided mental imagery.
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Aberrant motor cortex plasticity is hypothesized to contribute to chronic musculoskeletal pain, but evidence is limited. Critically, studies have not considered individual differences in motor plasticity or how this relates to pain susceptibility. Here we examined the relationship between corticomotor excitability and an individual's susceptibility to pain as pain developed, was sustained and resolved over 21 days. ⋯ PERSPECTIVE: This article explores individual differences in motor plasticity in the transition to sustained pain. Individuals who developed corticomotor depression experienced higher pain and worse cognitive task performance than those who developed corticomotor facilitation. Corticomotor depression in the early stage of pain could indicate a higher susceptibility to pain.