<i>In vivo</i> neuronal tract tracing using manganese‐enhanced magnetic resonance imaging

Pautler, Robia G.; Silva, Afonso C.; Koretsky, Alan P.

doi:10.1002/mrm.1910400515

Cited by 429 publications

(480 citation statements)

References 29 publications

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“…In support of this, it has been shown that the transport of Mn 2ϩ is reduced after the administration of the microtubule disrupting agent colchicine (16,29). The speed of axonal transport of Mn 2ϩ is estimated to be approximately 2-6 mm/hour (9,30), in the range of the velocity of fast axonal transport according to Grafstein and Forman (31). In addition to active transport, passive diffusion of Mn 2ϩ may, in theory, contribute to the Mn 2ϩ -enhanced signal observed in the visual pathway.…”

Section: Discussionmentioning

confidence: 88%

“…However, such techniques are not applicable to longitudinal studies because they require the study animals to be killed prior to tissue sectioning (9). The ability to perform in vivo serial MRI of CNS axon projections would constitute a major advance in neuroscience, and may in the future provide a diagnostic tool for conditions such as multiple sclerosis (MS), Parkinson's disease, and brain and spinal cord trauma.…”

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confidence: 99%

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Manganese‐enhanced MRI of the optic visual pathway and optic nerve injury in adult rats

Thuen¹,

Singstad

Pedersen³

et al. 2005

Magnetic Resonance Imaging

106

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Purpose: To evaluate manganese (Mn 2ϩ )-enhanced MRI in a longitudinal study of normal and injured rat visual projections. Materials and Methods:MRI was performed 24 hours after unilateral intravitreal injection of MnCl 2 (150 nmol) into adult Fischer rats that were divided into four groups: 1) controls (N ϭ 5), 2) dose-response (N ϭ 10, 0.2-200 nmol), 3) time-response with repeated MRI during 24 -168 hours post injection (N ϭ 4), and 4) optic nerve crush (ONC) immediately preceding the MnCl 2 injection (N ϭ 7). Control and ONC animals were reinjected with MnCl 2 20 days after the first injection, and MRI was performed 24 hours later. Results:In the control group, the optic projection was visualized from the retina to the superior colliculus, with indications of transsynaptic transport to the cortex. There was a semilogarithmic relationship between the Mn 2ϩ dose and Mn 2ϩ enhancement from 4 to 200 nmol, and the enhancement decayed gradually to 0 by 168 hours. No Mn 2ϩ -enhanced signal was detected distal to the ON crush site. In the control group, similar enhancement was obtained after the first and second MnCl 2 injections, while in the ONC group the enhancement proximal to the crush site was reduced 20 days post lesion (20dpl). Conclusion:Mn 2ϩ -enhanced MRI is a viable method for temporospatial visualization of normal and injured ON in the adult rat. The observed reduction in the Mn 2ϩ signal proximal to the ONC is probably a result of retrograde damage to the retinal ganglion cells, and not of Mn 2ϩ toxicity.

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Section: Discussionmentioning

confidence: 88%

mentioning

confidence: 99%

Manganese‐enhanced MRI of the optic visual pathway and optic nerve injury in adult rats

Thuen¹,

Singstad

Pedersen³

et al. 2005

Magnetic Resonance Imaging

106

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“…In contrast to low resolution BOLD-fMRI, MEMRI lends itself to study activity patterns in the brains of small animals at high resolution. In addition to our previous auditory studies (Yu et al, 2005;Yu et al, 2007), MEMRI has also been applied to study odor induced activity in the olfactory bulb (Pautler et al, 1998;Chuang et al, 2006), to examine light adaptation in retinal neurons (Berkowitz et al, 2006), to map cocaine-induced neuronal activation (Lu et al, 2007), and to detect hypothalamic activity (Morita et al, 2003;Chaudhri et al, 2006;Kuo et al, 2006) and ischemia-induced excitotoxicity (Aoki et al, 2003). Furthermore, MEMRI has been validated by correlation with BOLD and CBF (cerebral blood flow) functional maps in the somatosensory cortex of rats (Duong et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Statistical mapping of sound-evoked activity in the mouse auditory midbrain using Mn-enhanced MRI

Zou

Babb

et al. 2008

NeuroImage

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Manganese-enhanced MRI (MEMRI) has been developed to image brain activity in small animals, including normal and genetically modified mice. Here, we report the use of a MEMRI-based statistical parametric mapping method to analyze sound-evoked activity in the mouse auditory midbrain, the inferior colliculus (IC). Acoustic stimuli with defined frequency and amplitude components were shown to activate and enhance neuronal ensembles in the IC. These IC activity patterns were analyzed quantitatively using voxel-based statistical comparisons between groups of mice with or without sound stimulation. Repetitive 40-kHz pure tone stimulation significantly enhanced ventral IC regions, which was confirmed in the statistical maps showing active regions whose volumes increased in direct proportion to the amplitude of the sound stimuli (65dB, 77dB, and 89dB peak sound pressure level). The peak values of the activity-dependent MEMRI signal enhancement also increased from 7 to 20% for the sound amplitudes employed. These results demonstrate that MEMRI statistical mapping can be used to analyze both the 3D spatial patterns and the magnitude of activity evoked by sound stimuli carrying different energy. This represents a significant advance in the development of MEMRI for quantitative and unbiased analysis of brain function in the deep brain nuclei of mice.

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“…MEMRI is used to trace neuronal connections in vivo in the olfactory and visual pathways of mice and rats (7)(8)(9)(10). However, the method also allows specific brain areas that are active [activation-induced manganese-enhanced (AIM) MRI] to be highlighted, as demonstrated by Lin and Koretsky (11) upon glutamate injection into the common carotid artery.…”

Section: Fmri Methodologymentioning

confidence: 99%

“…The main reason is the difficulty of maintaining the physiological variables within the narrow boundaries dictated by the haemodynamic response. Several common anaesthesia protocols have been used in MEMRI studies, such as ketamine in birds (13) and urethane (33), pentobarbital (7) or isoflurane in mice [e.g. (34)] and songbirds, as safe and ultralight anaesthesia for auditory perception studies (12).…”

Section: Choice Of Anaesthesia and Effect On Brain Activationmentioning

confidence: 99%

Current status of functional MRI on small animals: application to physiology, pathophysiology, and cognition

et al. 2007

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This review aims to make the reader aware of the potential of functional MRI (fMRI) in brain activation studies in small animal models. As small animals generally require anaesthesia for immobilization during MRI protocols, this is believed to be a serious limitation to the type of question that can be addressed with fMRI. We intend to introduce a fresh view with an in-depth overview of the surprising number of fMRI applications in a wide range of important research domains in neuroscience. These include the pathophysiology of brain functioning, the basic science of activity, and functional connectivity of different sensory circuits, including sensory brain mapping, the challenges when studying the hypothalamus as the major control centre in the central nervous system, and the limbic system as neural substrate for emotions and reward. Finally the contribution of small animal fMRI research to cognitive neuroscience is outlined. This review avoids focusing exclusively on traditional small laboratory animals such as rodents, but rather aims to broaden the scope by introducing alternative lissencephalic animal models such as songbirds and fish, as these are not yet well recognized as neuroimaging study subjects. These models are well established in many other neuroscience disciplines, and this review will show that their investigation with in vivo imaging tools will open new doors to cognitive neuroscience and the study of the autonomous nervous system in experimental animals.

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In vivo neuronal tract tracing using manganese‐enhanced magnetic resonance imaging

Cited by 429 publications

References 29 publications

Manganese‐enhanced MRI of the optic visual pathway and optic nerve injury in adult rats

Manganese‐enhanced MRI of the optic visual pathway and optic nerve injury in adult rats

Statistical mapping of sound-evoked activity in the mouse auditory midbrain using Mn-enhanced MRI

Current status of functional MRI on small animals: application to physiology, pathophysiology, and cognition

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