The Guillain–Mollaret triangle (GMT) (blue) and its unidirectional course of inhibitory fibers, which ascend from the dentate nucleus (DN) to the contralateral red nucleus (RN) and then descend ipsilaterally to the inferior olivary nucleus (ION). The bilateral overlapping Guillain–Mollaret triangles together form a “tilted star of David configuration” (5). Fibers of the GMT, which is also called the dentato–rubro–olivary-pathway, overlap with dentato–thalamo–cortical pathways proceeding into both hemispheres (black arrow) (10). HOD, hypertrophic olivary degeneration; SCP, superior cerebellar peduncle; ICP, inferior cerebellar peduncle; RN, red nucleus; CTT, central tegmental tract; DN, dentate nucleus; ION, inferior olivary nucleus.