Dentate Nucleus: Connectivity-Based Anatomic Parcellation Based on Superior Cerebellar Peduncle Projections

Abstract

OBJECTIVE: Projections from the dentate nucleus (DN) follow a certain organized course to upper levels. Crossing and noncrossing fibers of the dentatorubrothalamic (DRT) tract terminate in the red nucleus and thalamus and have various connections throughout the cerebral cortex. We aimed to establish the microsurgical anatomy of the DN in relation to its efferent connections to complement the increased recognition of its surgical importance and also to provide an insight into the network-associated symp-toms related to lesions and microsurgery in and around the region. METHODS: The cerebellum, DN, and superior cerebellar peduncle (SCP) en route to red nucleus were examined through fiber dissections from the anterior, posterior, and lateral sides to define the connections of the DN and its relationships with adjacent neural structures. RESULTS: The DN was anatomically divided into 4 areas based on its relation to the SCP; the lateral major, lateral anterosuperior, posteromedial, and anteromedial compart-ments. Most of the fibers originating from the lateral compartments were involved in the decussation of the SCP. The ventral fibers originating from the lateral ante-rosuperior compartment were exclusively involved in the decussation. The fibers from the posteromedial compart-ment ascended ipsilaterally and decussated, whereas most anteromedial fibers ascended ipsilaterally and did not participate in the decussation. CONCLUSIONS: Clarifying the anatomofunctional orga-n ization of the DN in relation to the SCP could improve microneurosurgical results by reducing the complication rates during infratentorial surgery in and around the n ucleus. The proposed compartmentalization would be a major step forward in this effort.