Origin of a Non-Clarke’s Column Division of the Dorsal Spinocerebellar Tract and the Role of Caudal Proprioceptive Neurons in Motor Function

• DOI: 10.1016/j.celrep.2015.09.064
• Publication Date: 2015-11-03T08:02:08Z
• Authors: Rachel Yuengert; Kei Hori; Erin E. Kibodeaux; Jacob X. McClellan; Justin E. Morales; Teng-Wei P. Huang; Jeffrey L. Neul; Helen C. Lai
• Keywords: Neurons; Male; 0301 basic medicine; Afferent Pathways; Medulla Oblongata; Spinal Cord Dorsal Horn; QH301-705.5; Movement; Neurogenesis; Afferent; Inbred C57BL; Proprioception; Mice, Inbred C57BL; Mice; 03 medical and health sciences; Neural Stem Cells; Cerebellum; Basic Helix-Loop-Helix Transcription Factors; Animals; Cell Lineage; Female; Biochemistry and Cell Biology; Neurons, Afferent; Biology (General)

Proprioception, the sense of limb and body position, is essential for generating proper movement. Unconscious proprioceptive information travels through cerebellar-projecting neurons in the spinal cord and medulla. The progenitor domain defined by the basic-helix-loop-helix (bHLH) transcription factor, ATOH1, has been implicated in forming these cerebellar-projecting neurons; however, their precise contribution to proprioceptive tracts and motor behavior is unknown. Significantly, we demonstrate that Atoh1-lineage neurons in the spinal cord reside outside Clarke's column (CC), a main contributor of neurons relaying hindlimb proprioception, despite giving rise to the anatomical and functional correlate of CC in the medulla, the external cuneate nucleus (ECu), which mediates forelimb proprioception. Elimination of caudal Atoh1-lineages results in mice with relatively normal locomotion but unable to perform coordinated motor tasks. Altogether, we reveal that proprioceptive nuclei in the spinal cord and medulla develop from more than one progenitor source, suggesting an avenue to uncover distinct proprioceptive functions.