The
default mo
de network (DMN), a group of brain regions implicate
d in passive thought processes, has been propose
d as a potentially informative neural marker to ai
d in novel treatment
development. However, the DMN's internal connectivity an
d its temporal relationship (ie, functional network connectivity) with pain-relate
d neural networks in chronic pain con
ditions is poorly un
derstoo
d, as is the DMN's sensitivity to analgesic effects. The current stu
dy assesse
d how DMN functional connectivity an
d its temporal association with 3 pain-relate
d networks change
d after rectal li
docaine treatment in irritable bowel syn
drome patients. Eleven females with irritable bowel syn
drome un
derwent a rectal balloon
distension para
digm
during functional magnetic resonance imaging in 2 con
ditions: natural history (ie, baseline) an
d li
docaine. Results showe
d increase
d DMN connectivity with pain-relate
d regions
during natural history an
d increase
d within-network connectivity of DMN structures un
der li
docaine. Further, there was a significantly greater lag time between 2 of the pain networks, those involve
d in cognitive an
d in affective pain processes, comparing li
docaine to natural?history. These fin
dings suggest that 1) DMN plasticity is sensitive to analgesic effects, an
d 2) re
duce
d pain ratings via analgesia reflect DMN connectivity more similar to pain-free in
divi
duals. Fin
dings show potential implications of this network as an approach for un
derstan
ding clinical pain management techniques.
Perspective
This study shows that lidocaine, a peripheral analgesic, significantly altered DMN connectivity and affected its relationship with pain-related networks. These findings suggest that the DMN, which is hypothesized to represent non-goal-oriented activity, is sensitive to analgesic effects and could be useful to understand pain treatment mechanisms.