ELECTRICAL-STIMULATION OF THE CINGULUM BUNDLE AND SURROUNDING CORTICAL TISSUE REDUCES FORMALIN-TEST PAIN IN THE RAT

Citation
Pn. Fuchs et al., ELECTRICAL-STIMULATION OF THE CINGULUM BUNDLE AND SURROUNDING CORTICAL TISSUE REDUCES FORMALIN-TEST PAIN IN THE RAT, Brain research, 743(1-2), 1996, pp. 116-123
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences
Journal title
Brain research → ACNP
ISSN journal
0006-8993
Volume
743
Issue
1-2
Year of publication
1996
Pages
116 - 123
Database
ISI
SICI code
0006-8993(1996)743:1-2<116:EOTCBA>2.0.ZU;2-Z
Abstract
Surgical lesions of the cingulum bundle in humans produce marked decre ases in severe pain associated with cancer, reflex sympathetic dystrop hy and other forms of chronic pain. Similarly, a temporary block of th e anterior cingulum bundle in the rat by microinjection of lidocaine p roduces significant decreases in formalin-pain and reduces autotomy fo llowing peripheral neurectomy. The present study explored the effect o f electrical stimulation of the cingulum bundle/surrounding cortical t issue (CB/CT) on tonic pain in the rat. Experiment 1 examined changes in formalin-induced pain responses following a 2.5-min period (30 s/mi n for 5 min) of electrical stimulation of the CB/CT 15 min prior to th e formalin injection. The stimulation produced a significant reduction of first-period and second-period pain responses. Experiment 2 examin ed changes in formalin-induced pain responses following a 2.5-min peri od (30 s/min for 5 min) of electrical stimulation of the CB/CT 20 min following the formalin injection. The stimulation produced a dramatic reduction in second-period pain responses which persisted for the dura tion of the 35-min post-stimulation test period, The fact that either electrical stimulation or surgical section of the CB/CT produces pain relief suggests that this region serves a complex role in pain process ing. Since the cingulum bundle has major connections with all other st ructures of the limbic system, it is possible that electrical stimulat ion disrupts patterned activity in the system, which is known to play an especially important role in the affective-motivational dimension o f pain.