Abstract
Objective. Although acute pain has been shown to reduce corticomotor excitability, it remains unknown whether this
response resolves over time or is related to symptom severity. Furthermore, acute pain research has relied upon
data acquired from the cranial “hotspot,” which do not provide valuable information regarding reorganization, such
as changes to the distribution of a painful muscle’s representation within M1. Using a novel, rapid transcranial magnetic stimulation (TMS) mapping method, this study aimed to 1) explore the temporal profile and variability of corticomotor reorganization in response to acute pain and 2) determine whether individual patterns of corticomotor reorganization are associated with differences in pain, sensitivity, and somatosensory organization. Methods.
Corticomotor (TMS maps), pain processing (pain intensity, pressure pain thresholds), and somatosensory (two-point
discrimination, two-point estimation) outcomes were taken at baseline, immediately after injection (hypertonic
[n ¼ 20] or isotonic saline [n ¼ 20]), and at pain resolution. Follow-up measures were recorded every 15 minutes until
90 minutes after injection. Results. Corticomotor reorganization persisted at least 90 minutes after pain resolution.
Corticomotor depression was associated with lower pain intensity than was corticomotor facilitation (r ¼ 0.47
[P ¼ 0.04]). These effects were not related to somatosensory reorganization or peripheral sensitization mechanisms.
Conclusions. Individual patterns of corticomotor reorganization during acute pain appear to be related to symptom
severity, with early corticomotor depression possibly reflecting a protective response. These findings hold important
implications for the management and potential prevention of pain chronicity. However, further research is required
to determine whether these adaptations relate to long-term outcomes in clinical populations.
response resolves over time or is related to symptom severity. Furthermore, acute pain research has relied upon
data acquired from the cranial “hotspot,” which do not provide valuable information regarding reorganization, such
as changes to the distribution of a painful muscle’s representation within M1. Using a novel, rapid transcranial magnetic stimulation (TMS) mapping method, this study aimed to 1) explore the temporal profile and variability of corticomotor reorganization in response to acute pain and 2) determine whether individual patterns of corticomotor reorganization are associated with differences in pain, sensitivity, and somatosensory organization. Methods.
Corticomotor (TMS maps), pain processing (pain intensity, pressure pain thresholds), and somatosensory (two-point
discrimination, two-point estimation) outcomes were taken at baseline, immediately after injection (hypertonic
[n ¼ 20] or isotonic saline [n ¼ 20]), and at pain resolution. Follow-up measures were recorded every 15 minutes until
90 minutes after injection. Results. Corticomotor reorganization persisted at least 90 minutes after pain resolution.
Corticomotor depression was associated with lower pain intensity than was corticomotor facilitation (r ¼ 0.47
[P ¼ 0.04]). These effects were not related to somatosensory reorganization or peripheral sensitization mechanisms.
Conclusions. Individual patterns of corticomotor reorganization during acute pain appear to be related to symptom
severity, with early corticomotor depression possibly reflecting a protective response. These findings hold important
implications for the management and potential prevention of pain chronicity. However, further research is required
to determine whether these adaptations relate to long-term outcomes in clinical populations.
| Original language | English |
|---|---|
| Pages (from-to) | 1312-1323 |
| Number of pages | 12 |
| Journal | Pain Medicine |
| Volume | 22 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 1 Jun 2021 |