Brainstem experimental seizures produced by microinjections of carbachol.

Microinjections of 2-10 micrograms of carbachol into the mesencephalic reticular formation (MRF) and pontine reticular formation (PRF) of rats consistently induced local electroencephalographic seizures. These seizures had organized, rhythmical patterns and were long lasting. They spread powerfully and bilaterally between the MRF and PRF and also to the hippocampus and cortex. The electroencephalographic seizures were accompanied by severe, long-lasting convulsions. These convulsions were clonic and bilateral, started in the head area and progressed rostro-caudally to become generalized to the entire body. Other nonconvulsive behaviors were activated by the seizures. Immobility and catalepsy were the most frequent nonconvulsive correlates of the brainstem carbachol seizures.