Decreases in Neuron Density in the Compact Zone of the Substantia Nigra Correlate with Low Peak-Wave Activity in WAG/Rij Rats

WAG/Rij rats have a genetic predisposition to absenceepilepsy [7]. The first episodes of epileptic activity areknown to occur in these animals at age 3–6 months and tobe accompanied by characteristic peak-wave discharges onthe EEG with a maximum amplitude in the frontal areas ofthe neocortex [12].Peak-wave discharges have a generalized nature, i.e.,they affect a large part of the cortex [17], and the triggerzone for discharges is the somatosensory cortex [11].Autoradiographic studies of the brain in WAG/Rij ratshave established that a number of structures involved informing peak-wave discharges show changes in the expres-sion of dopamine types 1 and 2 receptors (D