Cortical control of generalized absence seizures: effect of lidocaine applied to the somatosensory cortex in WAG/Rij rats

Brain Res. 2004 Jun 25;1012(1-2):127-37. doi: 10.1016/j.brainres.2004.03.041.

Abstract

The role of the somatosensory cortex (SmI) in the incidence of spike-wave discharges (SWDs) was studied in a genetic model of absence epilepsy, WAG/Rij rats. SWDs were recently shown to initiate at the perioral area of the SmI and spread over the cortex and thalamus within a few milliseconds [J. Neurosci. 22 (2002) 1480]. It was hypothesized that functional deactivation of the SmI might reduce the appearance of SWDs. This was tested using unilateral microinjections (1 microl) of 2% lidocaine into the SmI in 13 WAG/Rij rats. Electrocorticogram (ECoG) was recorded in free moving animals from four cortical sites after lidocaine and control (saline) injections. Lidocaine effectively diminished the power of the ECoG spectra mostly in the area surrounding the injection site. Deactivation of the perioral region of the SmI reduced the incidence of SWDs at the entire cortex in both hemispheres. The number of SWDs gradually reached control level at the end of the second hour after injections of lidocaine. These data show that proper functioning of SmI is important for the occurrence of SWDs, supporting the idea that absence seizures might have a focal cortical origin.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / physiology
  • Epilepsy, Absence / drug therapy*
  • Epilepsy, Absence / physiopathology
  • Injections, Intraventricular
  • Lidocaine / administration & dosage*
  • Male
  • Rats
  • Rats, Inbred Strains
  • Somatosensory Cortex / drug effects*
  • Somatosensory Cortex / physiology

Substances

  • Lidocaine