Format

Send to

Choose Destination
Neurosci Res. 2015 Sep;98:35-44. doi: 10.1016/j.neures.2015.05.001. Epub 2015 Jun 17.

Histological and electrophysiological analysis of the corticospinal pathway to forelimb motoneurons in common marmosets.

Author information

1
Department of Physiology, Keio University School of Medicine, Tokyo, Japan.
2
School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Kanagawa, Japan.
3
Department of Physiology, Keio University School of Medicine, Tokyo, Japan; Japan Society for the Promotion of Science, Tokyo, Japan.
4
Department of Developmental Physiology, National Institute for Physiological Sciences, Aichi, Japan.
5
Division of Regenerative Medicine, Jikei University School of Medicine, Tokyo, Japan.
6
Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.
7
Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Kanagawa, Japan; Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan. Electronic address: ushiba@brain.bio.keio.ac.jp.

Abstract

Using histological and electrophysiological methods, we identified the neuroanatomical properties of the common marmoset corticospinal tract (CST), which underlies hand/arm motor control. Biotinylated dextran amine (BDA) was injected into the primary motor cortex to anterogradely label CST axons in the cervical segments, revealing that most CST axons descend in the contralateral dorsolateral funiculus (DLF; 85.0%), and some in the ipsilateral DLF (10.7%). Terminal buttons were mainly found in the contralateral lamina VII of the gray matter, but projection to lamina IX, where forelimb motoneurons are located, was rare. Bilateral projections were more abundant than found in the rat CST, resembling the CST organization of other primates. Intracellular recordings were made from 57 forelimb motoneurons on the contralateral side to stimulation, which revealed no monosynaptic excitatory postsynaptic potentials (EPSPs), but di- or polysynaptic EPSPs and inhibitory synaptic potentials were commonly found. Local field potentials showed monosynaptic excitation mainly in laminae VII, where abundant BDA-labeled CST terminals were observed. These results suggest that direct corticomotoneuronal projection is absent in common marmosets but di- or oligosynaptic effects would be mediated by spinal interneurons.

KEYWORDS:

Common marmoset; Corticospinal tract; Manual dexterity; Motoneuron; Non-human primate; Segmental interneuron

PMID:
26093181
DOI:
10.1016/j.neures.2015.05.001
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center