Electrical stimulation of cortex improves corticospinal tract tracing in rat spinal cord using manganese-enhanced MRI

Bilgen, Mehmet; Peng, Warner; Al-Hafez, Baraa; Dancause, Numa; He, Ye; Cheney, Paul D.

doi:10.1016/j.jneumeth.2006.02.001

Cited by 27 publications

(16 citation statements)

References 20 publications

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“…We followed established procedures described previously for the surgery, SCI, Mn delivery and MEI scans [8-10]. After SCI, the rat was left to recover for two weeks.…”

Section: Methodsmentioning

confidence: 99%

“…As an alternative method, we have shown that manganese-enhanced magnetic resonance imaging (MEI) can offer new possibilities in probing the SC in live animals [7,8]. MEI is an experimental technique that uses the paramagnetic manganese ion (Mn 2+ ) as a contrast agent.…”

Section: Introductionmentioning

confidence: 99%

“…Applying Mn directly into the SC just rostral to a hemisectioned SC, we have demonstrated that MEI can potentially play an important role in mapping viable neuronal tissue at and below the site of injury because functional tissue on the uninjured side takes up Mn and hence is delineated on the MEI [7]. Moreover, after intracortical administration of Mn into the motor areas of the brain and stimulating the cortex electrically, we have produced robust and detectable anterograde Mn labeling of the CST from cortex caudally to the thoracic SC levels [8]. The aim of the current study is determine whether MEI can detect CST connectivity in partially injured SC.…”

Section: Introductionmentioning

confidence: 99%

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Imaging corticospinal tract connectivity in injured rat spinal cord using manganese-enhanced MRI

Bilgen

2006

BMC Med Imaging

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BackgroundManganese-enhanced MRI (MEI) offers a novel neuroimaging modality to trace corticospinal tract (CST) in live animals. This paper expands this capability further and tests the utility of MEI to image axonal fiber connectivity in CST of injured spinal cord (SC).MethodsA rat was injured at the thoracic T4 level of the SC. The CST was labeled with manganese (Mn) injected intracortically at two weeks post injury. Next day, the injured SC was imaged using MEI and diffusion tensor imaging (DTI) modalities.ResultsIn vivo MEI data obtained from cervical SC confirmed that CST was successfully labeled with Mn. Ex vivo MEI data obtained from excised SC depicted Mn labeling of the CST in SC sections caudal to the lesion, which meant that Mn was transported through the injury, possibly mediated by viable CST fibers present at the injury site. Examining the ex vivo data from the injury epicenter closely revealed a thin strip of signal enhancement located ventrally between the dorsal horns. This enhancement was presumably associated with the Mn accumulation in these intact fibers projecting caudally as part of the CST. Additional measurements with DTI supported this view.ConclusionCombining these preliminary results collectively demonstrated the feasibility of imaging fiber connectivity in experimentally injured SC using MEI. This approach may play important role in future investigations aimed at understanding the neuroplasticity in experimental SCI research.

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“…We followed established procedures described previously for the surgery, SCI, Mn delivery and MEI scans [8-10]. After SCI, the rat was left to recover for two weeks.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Imaging corticospinal tract connectivity in injured rat spinal cord using manganese-enhanced MRI

Bilgen

2006

BMC Med Imaging

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“…Further, a number of studies suggest that the uptake and/or transport of manganese to specific terminal fields may be activity dependent (8,12,13). Similarly, the co-release of manganese with glutamate (14) suggests that trans-synaptic release into secondary terminal fields may also be activity dependent.…”

Section: Introductionmentioning

confidence: 99%

Quantitative manganese tract tracing: dose‐dependent and activity‐independent terminal labelling in the mouse visual system

Lowe¹,

Thompson

Sibson³

2008

NMR in Biomedicine

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At concentrations sufficient for visualisation using MRI, manganese (Mn) is believed to behave as a calcium analogue. This study examines different concentrations of Mn for enhanced MR tract tracing. The premise of activity-dependent axonal transport was also examined by partial or complete blockade of retinal ganglion cell activity. Quantitative T(1) maps and semi-quantitative normalised signal intensities in the superior colliculi facilitated assessment of applied intraocular concentrations and activity dependence, respectively. Varying the concentration of applied Mn revealed a non-monotonic profile, with optimal, unfavourable and undesirable effects noted: 25 mM proved optimal, showing a maximal decrease in T(1), whereas 400 mM was associated with no terminal-field enhancement. The estimated vitreal concentration for optimal transport of Mn (2 mM) is substantially lower than that used in previous studies of the mouse. Both the partial blockade of inputs to 50% of retinal ganglion cells by a mGluR6 glutamate agonist and the complete blockade of all retinal ganglion cell activity with tetrodotoxin failed to decrease the relative enhancement in the superior colliculus. The failure to prevent axonal transport of Mn by blocking activity (and therefore theoretically the intracellular influx) appeared to be paradoxical. The optimal vitreal concentration of Mn has previously been shown to facilitate massive intracellular uptake of Mn, competitively blocking calcium, and 1 mM Mn blocks neurotransmission pre-synaptically. These results suggest that, at concentrations required for optimal Mn-enhanced MRI tract tracing in the visual system of the mouse, the uptake and transport of Mn may be dominated by passive mechanisms, which may also block neurotransmission.

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“…MRI field strengths (in the clinic as well as the experimental setting) continue to increase, and, with them, potentially, the image resolution and image acquisition speed that can be achieved. Thus, with the possibility for progressively more precise imaging, the field of SCI MRI has attracted increasing interest (Bilgen et al, 2000(Bilgen et al, , 2001b(Bilgen et al, , 2006Burian and Hajek, 2004;Deo et al, 2006;Duncan et al, 1992;Elshafiey et al, 2002;Falconer et al, 1994;Fraidakis et al, 1998;Hackney et al, 1994a,b;Krzyzak et al, 2005;LeMay et al, 1996;Metz et al, 2000;Narayana et al, 2004;Weirich et al, 1990), including attempts to guide surgical tissue grafting strategies (Fraidakis et al, 2004) in the rat. Experimental in vivo SCI MRI has been increasingly tested; the hardware for very high field in vivo spinal cord MRI is available for small rodents, including mice (Behr et al, 2004;Bilgen et al, 2001aBilgen et al, , 2006Bonny et al, 2004;Elshafiey et al, 2002;Ford et al, 1994;Guizar-Sahagun et al, 1994;Narayana et al, 2004;Sykova and Jendelova, 2007;Weber et al, 2006), although the technique remains laborious and not without risk for the fragile SCI animals (Weber et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Rapid, postmortem 9.4T MRI of spinal cord injury: Correlation with histology and survival times

Scholtes

Phan-Ba

Theunissen

et al. 2008

Journal of Neuroscience Methods

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Electrical stimulation of cortex improves corticospinal tract tracing in rat spinal cord using manganese-enhanced MRI

Cited by 27 publications

References 20 publications

Imaging corticospinal tract connectivity in injured rat spinal cord using manganese-enhanced MRI

Imaging corticospinal tract connectivity in injured rat spinal cord using manganese-enhanced MRI

Quantitative manganese tract tracing: dose‐dependent and activity‐independent terminal labelling in the mouse visual system

Rapid, postmortem 9.4T MRI of spinal cord injury: Correlation with histology and survival times

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