Cholinergic projections from the parabigeminal nucleus (Ch8) to the superior colliculus in the mouse: a combined analysis of horseradish peroxidase transport and choline acetyltransferase immunohistochemistry.

Choline acetyltransferase (ChAT) immunocytochemistry, acetylcholinesterase histochemistry and muscarinic receptor autoradiography demonstrated a cholinergic innervation within the superior colliculus. A method for the concurrent visualization of ChAT and transported horseradish peroxidase showed that a major extrinsic source for this cholinergic input is in the parabigeminal nucleus. We have designated these cholinergic neurons as the Ch8 cell group.