Get access

Kindling of claustrum and insular cortex: comparison to perirhinal cortex in the rat

Authors

  • Paul Mohapel,

    Search for more papers by this author
    • *Present address: Restorative Neurology, Neurology Clinic, Wallenberg Neuroscience Center, University Hospital, SE-221 85 Lund, Sweden
  • Xia Zhang,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Greg W. Gillespie,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Jennifer Chlan-Fourney,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Darren K. Hannesson,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Shannon M. Corley,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Xin-Min Li,

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author
  • Michael E. Corcoran

    1. Departments of Psychology and Psychiatry, Neuropsychiatry Research Unit, University of Saskatechewan, 103 Wiggins Road, Saskatoon, SK, Canada
    Search for more papers by this author

: Dr M. E. Corcoran, Office of Research Services, Kirk Hall, Room 217, University of Saskatchewan, 117 Science Place, Saskatoon, SK, S7N 5C8, Canada.
E-mail: corcoran@admin.usask.ca

Abstract

The perirhinal cortex has recently been implicated in the kindling of limbic generalized seizures. The following experiments in rats tested the selectivity of the perirhinal cortex's epileptogenic properties by comparing its kindling profile with those of the adjacent insular cortex, posterior (dorsolateral) claustrum and amygdala. The first experiment examined the kindling and EEG profiles, and found that both the claustrum and insular cortex demonstrated rapid epileptogenic properties similar to the perirhinal cortex, including very rapid kindling rates and short latencies to convulsion. Furthermore, electrical stimulation of all three structures led to a two-phase progression through stage-5 seizures which had characteristics of both neocortical and amygdaloid kindling. In a second experiment rats were suspended in a harness to allow for more detailed documentation of both forelimb and hindlimb convulsions. With this procedure we were able to detect subtle yet unique differences in convulsion characteristics from each of the kindled sites and stage-5 seizure phases. Some of these convulsive parameters were correlated with changes in FosB/ΔFosB protein and BDNF mRNA expression measured two hours after the last convulsion. Overall, it appears that the perirhinal cortex is not unique in its property of rapid epileptogenesis. Moreover, the posterior claustrum exhibited the fastest kindling and most vigorous patterns of clonus, suggesting that it may be even more intimately associated with the motor substrates responsible for limbic seizure generalization than is the perirhinal cortex.

Ancillary