Neuroscience 2005 Abstract
| Presentation Number: | 481.18 |
|---|---|
| Abstract Title: | Long-range axon pruning of transient visual--spinal projection in mouse. |
| Authors: |
Liu, X.*1
; Low, L. K.1
; Coble, J. P.1
; Jones, E. G.1
; Cheng, H.1
1Center for Neurosci., Univ. of California, Davis, Davis, CA |
| Primary Theme and Topics |
Development - Axonal and Dendritic Development -- Axon growth and guidance: Other |
| Secondary Theme and Topics | Neural Excitability, Synapses, and Glia: Cellular Mechanisms<br />- Synaptic Plasticity<br />-- Other |
| Session: |
481. Axon Growth and Guidance II Poster |
| Presentation Time: | Monday, November 14, 2005 2:00 PM-3:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # B50 |
| Keywords: | synapse, motor system, corticospinal, electron microscopy |
Visual cortex sends out long range, transient axonal projections to spinal cord in early postnatal development and selectively eliminates these axons by the second postnatal week in the rat. The cellular mechanism for elimination of the transient visual-spinal axons is unknown and no detailed study has been carried out in the mouse. The aim of this study is to define the time course of selective axon pruning of the visual-spinal projection and to reveal how these transient axons and their terminals are eliminated. We injected the tracer DiI or biotinylated dextran amine (BDA) into the mouse visual cortex at postnatal day 3 (P3) and examined the visual-spinal axon projection between P7 and P15. From P7 to P9, a substantial number of labeled fibers from the visual cortex passed the caudal pons, entered the pyramid and a small number of fibers decussated and descended in the cervical segment of the spinal cord. Some axon collaterals derived from the dorsal tract innervated the gray matter. After P15, no visual-spinal axons were observed in the spinal cord. To study how the transient axon projections are eliminated, we are examining BDA labeled visual-spinal axons and terminals at the electron microscopic level and report the subcellular changes of these profiles during axon pruning at different postnatal ages. The study shows the detailed time course of the transient visual-spinal projection and provides high resolution images of pruning axons and terminals in the mouse; the result is crucial in identifying the cellular mechanism underlying remodeling of long range projections in the central nervous system.
Supported by NIH grant HD045757
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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