title: Caudal granular insular cortex is sufficient and necessary for the long-term maintenance of allodynic behavior in the rat attributable to mononeuropathy.
abstract: Mechanical allodynia, the perception of innocuous tactile stimulation as painful, is a severe symptom of chronic pain often produced by damage to peripheral nerves. Allodynia affects millions of people and remains highly resistant to classic analgesics and therapies. Neural mechanisms for the development and maintenance of allodynia have been investigated in the spinal cord, brainstem, thalamus, and forebrain, but manipulations of these regions rarely produce lasting effects. We found that long-term alleviation of allodynic manifestations is produced by discreetly lesioning a newly discovered somatosensory representation in caudal granular insular cortex (CGIC) in the rat, either before or after a chronic constriction injury of the sciatic nerve. However, CGIC lesions alone have no effect on normal mechanical stimulus thresholds. In addition, using electrophysiological techniques, we reveal a corticospinal loop that could be the anatomical source of the influence of CGIC on allodynia.
authors.affiliation: Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado 80309-0345, USA.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Benison
authors.forename: Serhiy
authors.initials: S
authors.lastname: Chumachenko
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Harrison
authors.forename: Steven F
authors.initials: SF
authors.lastname: Maier
authors.forename: Scott P
authors.initials: SP
authors.lastname: Falci
authors.forename: Linda R
authors.initials: LR
authors.lastname: Watkins
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Barth
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000293:injuries / Q000502:physiology*; D003911:Dextrans / Q000378:metabolism; D004195:Disease Models, Animal; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology; D007839:Functional Laterality; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006930:Hyperalgesia / Q000503:physiopathology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D011712:Pyramidal Tracts / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012585:Sciatica / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D003911:Dextrans; D058785:GABA-A Receptor Agonists; C076397:biotinylated dextran amine; D009118:Muscimol; D001710:Biotin