Abstract
Meynert described the "loop of the peduncular foot" (Schlinge des Hirnschenkelfusses), and its ganglion (Ganglion der Hirnschenkelschlinge) and related them to Reil's Substantia innominata and Gratiolet's Ansa peduncularis, from which he apparently built up his findings. Koelliker renamed the ganglion with the eponymous designation Meynert'sches Basalganglion (Meynert's basal ganglion), a name which endures to the present day, and described its topographical spread in relation to neighboring structures. Meynert and Koelliker also described aspects of cell composition of the ganglion (or nucleus) with a better account of the latter. Both, together with Reil and Gratiolet, were the outstanding personalities of the 19(th) century who performed the pioneering studies on basal formations of the forebrain. After these works, a considerable body of research appeared in the 20(th) century, with a focus on Meynert's basal nucleus and related structures. The development of further knowledge about these structures revealed their great importance in the activity of the brain, as evidenced in both normal and pathological states.