Loading...
Musculotopic organization of the motor neurons supplying the mouse hindlimb muscles: A quantitative study using Fluoro-Gold retrograde tracing
Tímea Bácskai Zoltan Rusznak George Paxinos Charles Watson
Tímea Bácskai
Zoltan Rusznak
George Paxinos
Charles Watson
Abstract
We have mapped the motor neurons (MNs) supplying the major hindlimb muscles of transgenic (C57/BL6J-ChAT-EGFP) and wild-type (C57/BL6J) mice. The fluorescent retrograde tracer Fluoro-Gold was injected into 19 hindlimb muscles. Consecutive transverse spinal cord sections were harvested, the MNs counted, and the MN columns reconstructed in 3D. Three longitudinal MN columns were identified. The dorsolateral column extends from L4 to L6 and consists of MNs innervating the crural muscles and the foot. The ventrolateral column extends from L1 to L6 and accommodates MNs supplying the iliopsoas, gluteal, and quadriceps femoris muscles. The middle part of the ventral horn hosts the central MN column, which extends between L2 and L6 and consists of MNs for the thigh adductor, hamstring, and quadratus femoris muscles. Within these longitudinal columns, the arrangement of the different MN groups reflects their somatotopic organization. MNs innervating muscles developing from the dorsal (e.g., quadriceps) and ventral muscle mass (e.g., hamstring) are situated in the lateral and medial part of the ventral gray, respectively. MN pools belonging to proximal muscles (e.g., quadratus femoris and iliopsoas) are situated ventral to those supplying more distal ones (e.g., plantar muscles). Finally, MNs innervating flexors (e.g., posterior crural muscles) are more medial than those belonging to extensors of the same joint (e.g., anterior crural muscles). These data extend and modify the MN maps in the recently published atlas of the mouse spinal cord and may help when assessing neuronal loss associated with MN diseases.
Keywords
hindlimb, spinal cord, motor neuron, retrograde tracing, musculotopic organization, 3D modeling
Date
2014
Type
Journal article
Journal
Brain Structure and Function
Book
Volume
219
Issue
1
Page Range
303-321
Article Number
ACU Department
School of Behavioural and Health Sciences
Faculty of Health Sciences
Faculty of Health Sciences
Relation URI
Source URL
Event URL
Open Access Status
License
File Access
Controlled