Five different cell groups can be identified in the medial cerebellar nucleus (left). Each projects to a specific downstream network of targets, which serve a set of related functions (bottom panel). For example, cells that project to the zona incerta (ZI; blue pathway) help control orientation, while cells that project to the nucleus reticularis gigantocellularis (NRG; yellow pathway) are involved in regulating posture. The projections highlighted here form only a small part of the actual elaborate networks shown by Fujita and colleagues. This approach could also be used to elucidate pathway-specific cell groups in the lateral cerebellar nucleus (right). This compartment presumably projects to similar parts of the cerebral cortex (dashed lines) through different hubs that probably serve higher cognitive functions. This illustrates how the medial and lateral cerebellum might complement each other, targeting similar, but distinct hubs that relay signals to partially overlapping areas in the brain. The cortex is shown in light orange, the cerebellum in dark orange, the brainstem in mustard and the thalamus (Thal) in light brown. CL refers to the centrolateral nucleus of the thalamus, PB to the parabrachial nucleus, VM to the ventromedial nucleus of the thalamus, and VII to the facial motor nucleus.
Image credit: Chris I. De Zeeuw, Willem S. van Hoogstraten and Valentina Riguccini (CC BY 4.0).