Identification of neurons relaying trigeminal nociceptive input onto subnucleus reticularis ventralis in the cat

After trigeminal tractotomy, neurons within the trigeminal subnucleus caudalis and adjacent subnucleus reticularis dorsalis failed to respond to mechanical stimulation of the trigeminal integument, but neurons responsive to noxious stimulation of the trigeminal region were found within subnucleus reticularis ventralis (SRV) of the caudal medulla oblongata. Neurons antidromically excited by electrical stimulation of the ipsi- or contralateral SRV were found within the reticular formation adjacent to the trigeminal subnuclei oralis and interpolaris. These neurons were also responsive to noxious stimulation of the ipsilateral trigeminal region. It was concluded that neurons relaying trigeminal nociceptive input onto SRV are located within this part of the reticular formation.