A number of investigators have suggested that the early and late phases of the formalin test are mediated by separate neural systems. Evidence is presented which suggests that in addition to a dissociation between the two phases based on nociceptor stimulation and inflammation, the late phase of the formalin test is also dependent upon plasticity in the central nervous system which occurs during the transient early phase. Selectively blocking neural activity during the early phase with local anesthetics given peripherally, or in the cingulum bundle or fornix, prevents the development of these changes. Locally anesthetizing the cingulum bundle, fornix or medial bulboreticular formation prior to testing in the late phase produces analgesia which exceeds the duration of the anesthetic. It was also demonstrated that a thermal injury to the hindpaw or electrical stimulation of the sciatic nerve prior to neurectomy produces changes in the pattern and severity of self-mutilation following peripheral neurectomy, suggesting that the injury is encoded and maintained in central structures.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74621 |
| Date | January 1990 |
| Creators | Vaccarino, Anthony Leonard |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001238696, proquestno: AAINN67661, Theses scanned by UMI/ProQuest. |
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