Ch3, cholinergic cells of diagonal gyrus
pars ventralis

Upper part of Archistriatum, pars ventralis: Intermediate arcopallium (AI)

Ventral part of Archistriatum, pars ventralis plus caudal part of Archistriatum: Posterior nucleus of the pallial amygdala (PoA)

Many divide pars principalis on the basis of the 'compass points,' yielding pars dorsalis, pars ventralis, pars medialis, pars lateralis, and pars posterioralis (often combined with pars ventralis to form "pars ventroposterioralis").