REGIONAL HYPOMETABOLISM IN AN ACUTE MODEL OF FOCAL EPILEPTIC ACTIVITYIN THE RAT

Focal epileptic activity can be expected to influence distant brain ar eas via far reaching connections. To investigate such interactions the effects of focal epileptic activity on the metabolism of the brain we re investigated in the rat cortex. Focal epileptic activity was induce d by the application of penicillin onto the motor cortex. The focus, a nd to a lesser extent homotopic contralateral brain areas, showed an i ncrease in the regional cerebral metabolic rate of glucose (rCMRGlc) a s measured by [C-14]deoxyglucose autoradiography, This focal hypermeta bolism was accompanied by widespread hypometabolism lateral to the foc us. The decrease of rCMRGlc occurred in somatosensory cortical areas b ut not in the motor cortex behind or in front of the focus, the perirh inal cortex or the occipital cortex. It was associated with an increas e in metabolic rate in the ventrolateral, ventroposteromedial, ventrop osterolateral and, in particular, posterior nuclei of the thalamus. It is hypothesized that the widespread reduction of rCMRGlc in the somat osensory cortical areas is due to inhibition via thalamic nuclei cause d by activity in the motor cortex.