Neuroscience 2005 Abstract
| Presentation Number: | 456.14 |
|---|---|
| Abstract Title: | Differential effects of dysmyelination and reduced axonal caliber on relaxation time (T2) by MRI in mice <i>in vivo.</i> |
| Authors: |
Chen, Y.*1,2
; Dyakin, V. V-.1,2
; Branch, C. A.2,3
; Veeranna, V.1
; Yuan, A.1
; Lewis, D. P-.1
; Guilfoyle, D.1
; Nixon, R.1,4,5
1Center for Dementia Research , Nathan S. Kline Inst., Orangeburg, NY 2Center for Advanced Brain Imaging, Nathan S. Kline Inst., Orangeburg, NY 3NY, 140 Old Orangeburg Road, Building 35, 10962, 4USA, 140 Old Orangeburg Road, Building 35, 10962, 5Dept., of Radiology and Neuroscience, 140 Old Orangeburg Road, Building 35, 10962, |
| Primary Theme and Topics |
Techniques in Neuroscience - Staining, Tracing, and Imaging Techniques |
| Secondary Theme and Topics | Disorders of the Nervous System<br />- Demyelinating Disorders<br />-- Human studies and animal models |
| Session: |
456. Imaging by MRI and PET II Poster |
| Presentation Time: | Monday, November 14, 2005 9:00 AM-10:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # VV86 |
| Keywords: | neurofilament, Shiverer |
Structural changes in both axon and myelin are observed in white matter injuries and have significant impact on the long-term disability of patients. In these disorders, clinical manifestations are not sufficient to determine the structural basis for neurological dysfunction and no convenient noninvasive biological markers to distinguish between myelin and axonal injury. Here we describe the use of in vivo quantitative MRI to quantify the transverse relaxation time (T2) in brains of shiverer mice lacking myelin and HM-DKO mice lacking neurofilaments. Shiverer mouse reduces myelin sheath formation in the CNS, and prevents glial-stimulated expansion of the calibers of axons without affecting neurofilament levels by electron microscope, Western blot, or immunocytochemistry. In HM-DKO, targeted disruption of heavy and medium subunits of neurofilaments drastically reduces light subunit and virtually eliminates neurofilaments from axons. The calibers of large myelinated axons are markedly reduced but the thickness and volume of myelin sheaths appear normal. T2 values in shiverer were markedly increased in all major white matter tracts (e.g. corpus callosum, 11%, p<0.001); by contrast, even though axonal calibers are more severely reduced in HM-DKO than in shiverer, HM-DKO exhibited minor T2 increases in some but not all white matter areas (e.g. corpus callosum, 4.7%, p=0.04). Our findings suggest that T2 is highly sensitive to changes in the state of myelination but relatively insensitive to changes in axon caliber or axonal neurofilament content. These findings may be relevant to the clinical detection and evaluation of MRI of white matter abnormalities in clinical settings.
Supported by National institute of Aging
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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