A bundle of wire that is mainly based on the acetylcholine-producing cell groups Ch5 and Ch6 and that primarily ends in various thalamusnuclei. The bundle of wires is considered one of the most important components of the "ascending reticular activation system", ARAS. It contains, in addition to the acetylcholinergic filaments of Ch5 in the TPP nucleus and from Ch6 of the dorsolateral tegment nucleus, also
(a) serotoninergic filaments derived from the nucleus raphes dorsalis;
(b) noradrenergic filaments from the locus coeruleus ; and
(c) dopaminergic filaments from area tegmentalis ventralis;