Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2025 Feb 19.
Published in final edited form as: Methods Mol Biol. 2018;1779:527–541. doi: 10.1007/978-1-4939-7816-8_33

In Vivo Evaluation of Neuronal Transport in Murine Models of Neurodegeneration using Manganese-Enhanced MRI

Anne Bertrand 1,2, Maria Baron 1, Dung M Hoang 1, Lindsay K Hill 1,3, Sebastian L Mendoza 1, Einar M Sigurdsson 4, Youssef Z Wadghiri 1,*
PMCID: PMC11837276  NIHMSID: NIHMS2050930  PMID: 29886555

Abstract

Manganese-Enhanced MRI (MRI) is a technique that allows for a non-invasive, in vivo estimation of neuronal transport. It relies on the physicochemical properties of manganese, which is both a calcium analogue being transported along neurons by active transport, and a paramagnetic compound that can be detected on conventional T1 weighted images. Here we report a multi session MEMRI protocol that helps establish time dependent curves relating to neuronal transport along the olfactory tract over several days. The characterization of these curves via unbiased fitting enables to infer objectively a set of three parameters (the rate of manganese transport from the maximum slope, the peak intensity and the time to peak intensity). These parameters, measured previously in wild type mice during normal aging, have served as a baseline to demonstrate their significant sensitivity to pathogenic processes associated with Tau pathology. Importantly, the evaluation of these three parameters and their use as indicators can be extended to monitor any normal and pathogenic processes where neuronal transport is altered, This approach can be applied to characterize and quantify the effect of any neurological disease conditions on neuronal transport in animal models, together with the efficacy of potential therapies.

Keywords: MRI, manganese-enhanced MRI, manganese, axonal transport, neuronal transport, in vivo, imaging, longitudinal

1. Introduction

Axonal transport is essential for neuronal function, as synapses can be located up to a meter away from the neuronal cell body. Fast axonal transport allows for the movement of organelles along microtubules, at a rate of approximately 50–400 mm/day [1]. This transport is driven by kinesins, which move organelles anterogradely from the cell body to the axon terminals; and dyneins, which carry organelles retrogradely [1]. Slow axonal transport conveys soluble and cytoskeletal proteins at a slower pace, approximately 0.2-1mm/day [2].

There is growing evidence that impairment in axonal transport is a key pathological mechanism in neurodegenerative disorders. Mutations of axonal transport-related proteins have been identified in patients with neurodegenerative diseases [3–7]. Microscopy studies have demonstrated impaired axonal transport, in animal models of various neurodegenerative disorders (e.g. Alzheimer’s disease, amyotrophic lateral sclerosis and Parkinson’s disease) [8]. Various mechanisms may impair this transport, such as defects in cytoskeletal organization, deficient motor protein attachment to microtubules, flawed motor–cargo binding, and/or mitochondrial dysfunction.

Live microscopic video-imaging of neurons can strikingly capture the axonal transport of cargoes; however, this method is in essence limited to small regions of interest in single axons [9,10]. Invasive methods, such as nerve ligation or injection of radiolabeled tracers [11,12], allow for a global quantification of axonal transport, but are limited to post-mortem tissues, and cannot provide longitudinal follow-up studies. In contrast, manganese-enhanced magnetic resonance imaging (commonly termed MEMRI) can provide a non-invasive, in vivo assessment of axonal transport at the macroscopic scale.

MEMRI is based on two important physicochemical properties of manganese (Mn2+). The first valuable attribute of manganese is that it is a calcium-analogue; hence it can be internalized by neurons via the calcium (Ca2+) channel [13–16]. Intracellular manganese can then be transported along the microtubule system [15–17], prior to its release into the synaptic cleft by pre-synaptic vesicles [17]. The synaptic manganese can then be taken up by the post-synaptic neuron [17–22]. The second attribute owes to its paramagnetic properties for which manganese was the first element suggested for boosting the MRI signal of a phantom in Lauterbur’s seminal paper in 1973 [23]. Manganese chloride was subsequently used as an effective tissue signal enhancer by the same group [24] and others [25] where its accumulation causes a local increase in longitudinal relaxation R1 in the tissue at its vicinity. The rise in R1 translates into an increase of MR signal intensity that can be detected on T1-weighted (T1-w) images [26,27]. Therefore, by repeated MR examinations over time, manganese displacement can be monitored throughout the neurons [19,28–43]. Because three-dimensional (3D) T1-w MRI acquisitions can survey the entire mouse brain in less than fifteen minutes [33,36,37–39], repeated MEMRI can easily provide cerebral maps of manganese progression throughout the olfactory tract that can be used to infer the rate of transport. For these reasons, MEMRI has been proposed as an ideal non-invasive in vivo tool for the study of axonal transport in animal models of neurodegeneration using either two-dimensional (2D) [19,29,30,34,35,40–43] or 3D serial MRI acquisition [31–33,36–39], even though it is expected to reflect both axonal and dendritic transport (herein referred to as “neuronal transport”).

Most of these studies rely on a single image acquisition proving to be very effective in monitoring the rate of Mn2+ under various experimental conditions. The single imaging acquisition protocol is technically simple to implement and consists of 2D T1-weighted MRI repeated serially within the same session in less than one hour. However, this imaging protocol is highly dependent on the physiological conditions of each subject examined with the following minimal parameters to control: 1) body temperature; 2) respiratory breathing rate, and; 3) associated anesthetic inhaled or administered. These parameters are particularly prone to large variations depending on the mouse strain, age and stage of the pathology examined which renders this protocol less robust.

Our group devised a multisession imaging protocol more resistant to these physiological changes [36,37] where the subject is scanned for fifteen minutes at different timed intervals. Even though the physiology of the subject scanned during the fifteen minute session may be compromised, the overall impact is considered negligible. This consideration takes into account that the scan session is at least 12-fold shorter in duration than the active period, where subjects are fully awake and functional between scans. These active periods span anywhere from 3 hours to multiple days. Our imaging strategy proved to be a very sensitive method to evaluate the deleterious effect of tau pathology on Mn2+ neuronal transport in transgenic mouse models of tauopathy [36]. Importantly, the obtained image datasets are based on 3D acquisition with isotropic resolution. It allows to retrospectively re-examine the effect on Mn2+ transport in any anatomical orientation of the brain and throughout the olfactory tract, in which the expression of the pathology can be variable and not known a priori.

This chapter describes the experimental steps and 3D imaging strategy that we have successfully implemented and in which we established time curves from different regions of interest (roi) along the olfactory tract based on the serial acquisition of data. These experimental time curve data are then fitted and the plots are characterized by three parameters that we have shown to be sensitive to neuronal transport alterations [33,36–39]. Although we have above all used this approach to examine and correlate the effects of tau [36] or Aβ pathology [37] on neuronal transport in mouse models, it can be extended to evaluate the response to newly developed therapeutic interventions such asimmunotherapies [38,39] or in any model of neurodegenerative disease and to examine any animal that fits in the scanner.

2. Materials

2.1. Manganese Preparation (5 M solution of MnCl2)

2.1.1. Equipment

  • analytical balance, vortex mixer

2.1.2. Supplies

  • Manganese (II) chloride tetrahydrate (molecular weight 197.91 g/mol)

  • 0.9% sodium chloride solution

  • 1.5 ml eppendorf tube

  • Aluminum foil

2.2. MR Microimaging System

2.2.1. Equipment

  • MR microimaging (μMRI) scanner: Preferably, mouse brain imaging experiments should be performed at a magnetic field strength of at least 7-T. The experiments described in this chapter were performed on a Bruker Biospec Avance 2 console interfaced to a 7-T 200-mm horizontal bore magnet (Magnex Scientific, UK) equipped with actively shielded gradient coils (BGA-9S: ID = 90 -mm, 750-mT/m gradient strength, 100-μs rise time). Scanners with very similar performances have also been made by other manufacturers such as Agilent Technologies (Varian, Santa Clara, CA, USA).

  • MRI probe: A radiofrequency (RF) coil fitting closely around the mouse’s head should be used for brain imaging. In these experiments, we used a small birdcage quadrature RF coil dedicated for mouse head imaging that was developed in-house. The coil resonates at a proton frequency of 300 MHz. Its inner diameter (ID=21.5 mm) was designed to fit closely around the mouse’s head. The length (L) along the magnet bore (L= 29 mm) was selected to compromise between high coil sensitivity and magnetic field homogeneity over the mouse brain. The coil is fitted with a waterbed to keep the mouse’s body temperature stable during scanning.

  • Mouse holder: The RF coil should be incorporated into a holder that stabilizes the mouse’s head during MRI and can be fitted with devices for gas anesthesia delivery and physiological monitoring. MR compatible mouse holders are becoming available from commercial vendors of small animal MRI systems as well as RF coils, but most reports to date have used custom-holding devices. We have developed our own holder, incorporating the mouse head coil, a nose cone for isoflurane anesthesia, and several physiological-monitoring devices. The main design goal of the mouse holder should be to hold the head in a stationary and reproducible position during the 15 minutes that the animal must be maintained inside the magnet. Predictably, the design closely resembles a stereotaxic injection device, but is fabricated from nonmetallic MRI compatible materials. The head holder should be equipped with a calibrated tooth bar allowing enough vertical and horizontal range (5–10 mm) to center any brain region of interest within the RF coil. Ear bars would be helpful to further stabilize the mouse head, but most RF coil designs are not open structures, and it is difficult to incorporate ear bars within the close-fitting head coil.

  • Gas anesthesia: Isoflurane vaporizer/anesthesia machine (VMS Matrix Medical, Orchard Park, NY).

  • Physiological monitoring system

  • Surgery hood

  • Surgery microscope

2.2.2. Supplies

  • Isoflurane (Aerane, Baxter, Deerfield, IL).

  • Induction chamber

  • Multichannel micropipette, with a minimum range of 1–10μL

  • 1-10 filtered pipette tips

  • Surgery hood

  • Surgery microscope

  • Heating pad

  • Paper towels

3. Methods (5 M solution of MnCl2)

3.1. Manganese Preparation

  • To prepare (5 M solution of MnCl2), weight 247.4 mg of MnCl2 4H2O (molecular weight=197.91) on an analytical scale. Transfer the weighted amount to a 1.5 ml eppendorf tube and mix with 250 μl of 0.9% NaCl by vortexing briefly until the MnCl2 4H2O has completely dissolved.

  • Keep solution away from light by covering the Eppendorf tube with aluminum foil and refrigerate until ready to use. Discard after use.

3.2. Manganese Administration

  • Allow the MnCl2 solution to come to room temperature.

  • Prepare the surgery hood by setting a heated stage such as a pad to a low setting and connecting an isoflurane line near the top portion of the heating pad.

  • Connect the induction chamber to the vaporizer and line the induction chamber with paper towels

  • Anesthetize the mouse with isoflurane: place the mouse in the induction chamber with 5% isoflurane in air for 3 min

  • Take the mouse outside the induction chamber and place it on the heating pad on its back with the face mask fitted to deliver continuously isoflurane. Wait until the breathing slows down and deepens

  • Aspirate 1.5 μL of 5 M MnCl2 using a 1-10 ul micropipette
    1. Hold the mouse by the scruff and tilt the head back. Place the mouse under the surgical microscope and focus on the mouse’s nostrils.

  • Gently introduce the pipette tip within a nostril of the mouse, and slowly administer the manganese solution, maintaining the tip of the pipette within the nostril.

  • Gently place the mouse on its back on the heating pad with the rostrum facing the isoflurane line and let it rest about one minute until the breathing rate slows down. This is done to delay the cough reflex and to ensure a correct and complete penetration of Mn2+ into the nasal epithelium (see Note 1).

  • Lower the isoflurane between 1% and 1.5% and allow the mouse to rest for an additional two minutes.

  • Transfer the mouse back to an individual mouse cage placed over a heating pad.

  • Allow the mouse to wake up without disturbance.

3.3. MRI Acquisition

3.3.1. Mouse setup

  • Anesthetize the mouse with isoflurane: 5% isoflurane in air for 3 min to induce anesthesia, followed by 1–1.5% isoflurane in air to maintain anesthesia. Care should be taken to properly secure the mouse in the holder before MRI.

  • After locking the upper incisors in the tooth bar, press gently with the index finger just above the nose to avoid unhooking the teeth while pulling the tail taut and immobilizing it with tape. (see Note 2).

  • Place the mouse’s head inside the MRI probe and turn on the water bath to heat the water bed attached to the probe. The use of a waterbed allows for maintaining the body temperature of the animal at 35-37°C (see Note 3).

  • Place the respiration monitor pillow in between the mouse’s belly and the holder. Check for the respiration signal in the physiological monitoring system.

  • Insert the whole setup with the mouse head inserted within the probe in the magnet and tune and match the radiofrequency coil accordingly.

3.3.2. Slice alignment

  • Three orientations of 1-mm thick multi-slices are acquired simultaneously as orthogonal pilot orientations to achieve accurate image alignment after a few iterations, ensuring reproducible positioning of the 3D-T1 sequence between imaging sessions. Pilot scans are typically low resolution MR images, acquired in 2-3 minutes at most, and provide anatomical landmarks adequate to position the 3D sequence so that the brain is acquired in a symmetrical orientation (Figure 1).

Figure 1.

Figure 1

Open in a new tab

Example of orthogonal pilot images (1-mm thick) acquired simultaneously within 2-3 minutes to induce multi-slice saturation slabs (seen as dark stripes) that serve as anatomical landmarks. This sequence is run at the beginning of the protocol as an iterative alignment process in order to refine the adequate positioning of the 3D sequence and enable the acquisition of the head in a symmetrical fashion. The image shown in A) relates to the horizontal orientation while B) and C) orientations correspond to coronal and sagittal slices respectively.

3.3.3. 3D T1-weighted sequence acquisition

  • Our customized protocol consists of nine, 15 minute long imaging sessions: Time zero session is acquired prior to manganese instillation; times 1h, 4h, 8h, 12h, 24h, 36h, 48h and 7 days correspond to the delay after the administration of manganese chloride, (5). The advantage of this protocol is that it provides a complete curve of manganese-related signal intensity changes, i.e. an increase followed by a decrease.

  • Each scan is a 3D T1-SPGR sequence with the following parameters: FOV = 19.2 × 19.2 × 9.6 mm, matrix size = 128 × 128 × 64, spatial resolution = (150μm)3, repetition time TR = 15-ms, echo time TE = 4-ms, averages = 6, acquisition time = 15 min. We recommend to calculate the flip angle (FA) to provide the greatest T1-enhancement contrast [44] (see Note 4).

  • During MR imaging, keep the mouse under anesthesia using isoflurane in air (1-2%).

  • Respiratory rate should be constantly monitored in order to adjust the level of anesthesia where breathing rate of the animal should remain between 40 and 60 breaths per minute.

  • After MR imaging, remove the mouse from the mouse holder and place it on a heating pad for a few minutes until it is awake; then transfer it back to its cage until the next scan.

2.5.4. Image Post Processing

  • 3D T1-weighted images are processed using the ImageJ software (NIH, Rockville, MD)

  • Perform a rigid registration between the 9 MRI datasets acquired serially from each mouse and corresponding at 9 different time points, using the open source image processing program ImageJ with the rigid registration plugin (Rigid_Registration.jar plugin, J Schindelin, M Longair) which can be found at the ImageJ public domain website. It is Java-based image processing program developed at the National Institutes of Health and designed for scientific multidimensional images.

  • Define regions of interest within the olfactory system for quantification of the change in signal intensity. We use three regions of interest (ROI): the glomerular layer, the mitral cell layer and the anterior part of the piriform cortex (Figure 2A and B). We also use the pons as a fourth ROI for normalization of signal intensities at each time point (Figure 3A and B) (see Note 5). ROI are placed using a mouse brain atlas.

  • Normalized signal intensities in each ROI can be plotted over time and reflect the bulk progression of manganese in the ROI.

  • The resulting plots can then be fitted to a Fokker-Planck equation using MATLAB scripts described in [36]. The fitted line plot obtained can then be characterized using the following quantitative parameters: value of the peak of intensity (Pv), time-to-peak of intensity (Pt), and maximal value of the ascending slope (Sv) (Figure 4).

Figure 2.

Figure 2

Open in a new tab

The two sagittal views of the mouse brain shown here are obtained from an interpolation by doubling the matrix size of the 3D datasets from 128×128×64 to 256x256x128. Both data are acquired from the same subject before (A) and 24 hours after (B) nasal instillation of 1.5 micro-liter of 5 M solution of manganese chloride. The 150-μm isotropic resolution enables the virtual re-sectioning in any orientation retrospectively without compromising the anatomical detail. With the guidance of a mouse atlas, the sagittal section chosen helps delineate a large portion of the olfactory tract including the olfactory epithelium (blue arrowheads), the outer layers of the olfactory bulb (red dotted arrows) and the piriform cortex (yellow arrows). The dorsal-to-ventral anatomical locations of the two horizontal views shown in (C) and (D) can be seen in color-matched sections depicted in the coronal orientation from the same dataset in (A). The red boxes insert shown in (C) correspond to anatomical regions of interest related: 1) glomerular cell layer and 2) mitral cell layer; and in (D) to the piriform cortex

Figure 3.

Figure 3

Open in a new tab

The 150-μm isotropic resolution of the serial 3D datasets acquired through multiple days facilitates the realignment of all the acquisitions and enable the examination of the region of interest in any orientation among the 9 time points collected over 7 days. The example shown here is taken from a subject prior to manganese instillation and 24 hours following the manganese propagation within the olfactory tract. Similar to the examples shown in Figure 2, the section shown are in the horizontal orientation (which correspond to the coronal orientation for the mouse body) but this time the data are visualized in their native matrix size (128x128x64) with no interpolation; hence the more pixelized images. In addition to the regions of interest in the olfactory bulb described previously and that include the glomerular cell layer (GCL) and the mitral cell layer (MCL) shown in (A), the anterior piriform cortex (APC) and the posterior piriform cortex (PPC) can be identified by the red squares as well as the pons used to normalize signal intensities at each time, as shown in (C).

Figure 4.

Figure 4

Open in a new tab

Time curve illustrating the fitting of the signal intensity values over a 7–day period which is characterized by the following parameters: peak value, maximal slope and time to peak. These measurements can be compared between animals, and correlated with other outcomes such as behavioral assays as well as histological and biochemical measures.

Conclusions

The use of serial MEMRI to investigate the olfactory tract has been shown to be a very effective tool to monitor noninvasively and longitudinally the impairment of neuronal transport during normal aging and in mouse models of Alzheimer’s disease.

The multisession 3D imaging protocol described in this chapter, although costly in scanning time, enables the examination of the whole olfactory tract thanks to the isotropic resolution of the serial imaging datasets. This allows researchers to investigate retrospectively the properties of neuronal transport in any orientation and at any level of the brain without knowing a priori which brain region may be affected.

Acknowledgements

This work was supported by the following grants: AG032611 and AG020197, and a Zenith grant from the Alzheimer Association to EMS; Alzheimer Association IIRG-08-91618 and American Health Assistance Foundation Alzheimer Disease Research Grant A2008-155 to YZW.

Notes

(1)

Just after MnCl2 instillation of the manganese solution, it is important to maintain the mouse under its back under deep anesthesia, to prevent the coughing reflex and ensure a complete absorption of the manganese solution. However, extra care should be taken not to use too high volume of the manganese solution as it can impair breathing and result in sudden death. In our experience, 1.5 μL is an acceptable volume for this procedure.

(2)

This simple approach has proved to be very effective for reducing motion artifacts and has provided high-quality MR brain images. A detailed description of this approach can be found in Wadghiri et al. , 2012 [45]

(3)

In our experience, it is very difficult to keep a constant body temperature of 37°C under deep anesthesia. At 37°C, most animals will not be fully asleep, which causes motion artifacts on MR images. A slight hypothermia is acceptable for this protocol, because axonal transport occurs mainly between the scanning sessions, when animals are awake. Such slight hypothermia ensure an efficient anesthesia which prevents the occurrence of motion artifacts.

(4)
The choice of flip angle is critical for determining both signal intensity as well as image contrast. On the current protocol, the flip angle (FA or also termed α in equations) must be calculated to maximize the T1-contrast based on an equation derived initially by Buxton et al., 1987 [46] and subsequently simplified by Neelavalli et al., 2007 [44]. The calculation was assessed in reference to the Ernst angle (αEA) which gives the maximum signal for a given tissue [47]. The quick rule of thumb expression for estimating the flip angle αTC for optimal T1-contrast is as follow [44]:
αTC≈√3×αEA→withTR≪T1
This is a very useful and straightforward expression as researchers are systematically required to estimate experimentally the Ernst angle when establishing a new imaging protocol at a given repetition time TR in order to perform the MRI scans under optimal signal conditions. The Ernst angle can be inferred based on the a priori knowledge of the relaxation properties of the region investigated from the following equation:
αEA=arccos(e−TR/T1)

where T1 is the longitudinal relaxation time of the tissue examined; in our case brain tissue in which the size of the voxels experience a partial volume effect mixing multiple types of tissues such as gray matter and white matter. T1 of the tissue is also dependent on the static magnetic field strength of the MRI instrument. Furthermore, this equation assumes ideal experimental conditions that are very often unmet such as accounting for hardware imperfections including the profile of the RF pulse or the field inhomogeneity of the RF coil. It must be noted that this equation is restricted to a class of frequently used gradient echo (GE) sequences where transverse coherences are purposely disrupted and commonly termed spoiled gradient echo. The choice of the repetition time TR on the other hand is dictated by a trade-off between the performance of the hardware equipping the scanner (gradient strength and duty cycle) and the spatial resolution chosen to acquire the dataset. In the current protocol, the 3D-GE T1-weighted imaging sequence we use to cover the whole mouse brain can range between 15-ms and 150-ms.

By taking into account all of the experimental limitations and the hardware performance of each scanner, it is therefore highly recommended to measure empirically the Ernst angle αEA for a given TR by seeking the maximum signal.

(5)

We do not use the contralateral side of the brain for normalization, as some degree of contralateral enhancement is usually observed, due to the frequent passage of Mn2+ in the contralateral nostril of the animal during the administration of the solution. Coughing reflex favors the contamination of the contralateral nostril, and can be prevented by efficient anesthesia after injection.

References

  • 1.Maday S, Twelvetrees Alison E, Moughamian Armen J, Holzbaur Erika LF (2014) Axonal Transport: Cargo-Specific Mechanisms of Motility and Regulation. Neuron 84 (2):292–309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.D.L. S, S.T. B (1999) Slow Axonal Transport. In: S GJ, A BW, A RW, F SK, U MD (eds) Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6 edn. Lippincott-Raven, Philadelphia, PA, USA. [Google Scholar]
  • 3.Chevalier-Larsen E, Holzbaur ELF (2006) Axonal transport and neurodegenerative disease. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease 1762 (11):1094–1108. [DOI] [PubMed] [Google Scholar]
  • 4.Duncan JE, Goldstein LSB (2006) The Genetics of Axonal Transport and Axonal Transport Disorders. PLOS Genetics 2 (9):e124. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Liu X-A, Rizzo V, Puthanveettil SV (2012) Pathologies Of Axonal Transport In Neurodegenerative Diseases. Translational neuroscience 3 (4):355–372. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Gibbs KL, Greensmith L, Schiavo G (2015) Regulation of Axonal Transport by Protein Kinases. Trends in Biochemical Sciences 40 (10):597–610. [DOI] [PubMed] [Google Scholar]
  • 7.De Vos KJ, Hafezparast M (2017) Neurobiology of axonal transport defects in motor neuron diseases: Opportunities for translational research? Neurobiology of Disease 105 (Supplement C):283–299. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Millecamps S, Julien J-P (2013) Axonal transport deficits and neurodegenerative diseases. Nat Rev Neurosci 14 (3):161–176. [DOI] [PubMed] [Google Scholar]
  • 9.Bearer EL, Zhang X, Jacobs RE (2007) Live Imaging of Neuronal Connections by Magnetic Resonance: Robust Transport in the Hippocampal-Septal Memory Circuit in a Mouse Model of Down Syndrome. NeuroImage 37 (1):230–242. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Gibbs KL, Kalmar B, Sleigh JN, Greensmith L, Schiavo G (2016) In vivo imaging of axonal transport in murine motor and sensory neurons. Journal of Neuroscience Methods 257:26–33. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Brown A (2003) Live-cell imaging of slow axonal transport in cultured neurons. Methods in cell biology 71:305–323. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Ittner LM, Fath T, Ke YD, Bi M, van Eersel J, Li KM, Gunning P, Götz J (2008) Parkinsonism and impaired axonal transport in a mouse model of frontotemporal dementia. Proceedings of the National Academy of Sciences of the United States of America 105 (41):15997–16002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Zhang B, Higuchi M, Yoshiyama Y, Ishihara T, Forman MS, Martinez D, Joyce S, Trojanowski JQ, Lee VMY (2004) Retarded Axonal Transport of R406W Mutant Tau in Transgenic Mice with a Neurodegenerative Tauopathy. The Journal of Neuroscience 24 (19):4657. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Narita K, Kawasaki F, Kita H (1990) Mn and Mg influxes through Ca channels of motor nerve terminals are prevented by verapamil in frogs. Brain Research 510 (2):289–295. [DOI] [PubMed] [Google Scholar]
  • 15.Drapeau P, Nachshen DA (1984) Manganese fluxes and manganese-dependent neurotransmitter release in presynaptic nerve endings isolated from rat brain. The Journal of Physiology 348:493–510. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Lu H, Xi Z-X, Gitajn L, Rea W, Yang Y, Stein EA (2007) Cocaine-induced brain activation detected by dynamic manganese-enhanced magnetic resonance imaging (MEMRI). Proceedings of the National Academy of Sciences of the United States of America 104 (7):2489–2494. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Sloot WN, Gramsbergen J-BP (1994) Axonal transport of manganese and its relevance to selective neurotoxicity in the rat basal ganglia. Brain Research 657 (1):124–132. [DOI] [PubMed] [Google Scholar]
  • 18.Takeda A, Kodama Y, Ishiwatari S, Okada S (1998) Manganese Transport in the Neural Circuit of Rat CNS. Brain Research Bulletin 45 (2):149–152. [DOI] [PubMed] [Google Scholar]
  • 19.Smith KDB, Kallhoff V, Zheng H, Pautler RG (2007) In Vivo Axonal Transport Rates Decrease In A Mouse Model Of Alzheimer’s Disease. NeuroImage 35 (4):1401–1408. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Saleem KS, Pauls JM, Augath M, Trinath T, Prause BA, Hashikawa T, Logothetis NK (2002) Magnetic Resonance Imaging of Neuronal Connections in the Macaque Monkey. Neuron 34 (5):685–700. [DOI] [PubMed] [Google Scholar]
  • 21.Tjälve H, Mejàre C, Borg-Neczak K (1995) Uptake and Transport of Manganese in Primary and Secondary Olfactory Neurones in Pike. Pharmacology & Toxicology 77 (1):23–31. [DOI] [PubMed] [Google Scholar]
  • 22.Tjälve H, Henriksson J, Tallkvist J, Larsson BS, Lindquist NG (1996) Uptake of Manganese and Cadmium from the Nasal Mucosa into the Central Nervous System via Olfactory Pathways in Rats *. Pharmacology & Toxicology 79 (6):347–356. [DOI] [PubMed] [Google Scholar]
  • 23.Lauterbur PC (1973) Image Formation by Induced Local Interactions: Examples Employing Nuclear Magnetic Resonance. Nature 242 (5394):190–191 [PubMed] [Google Scholar]
  • 24.Lauterbur PC, Dias MHM, Rudin AM (1978) Augmentation Of Tissue Water Proton Spin-Lattice Relaxation Rates By In Vivo Addition Of Paramagnetic Ions. In: Electrons to Tissues. Academic Press, pp 752–759. [Google Scholar]
  • 25.Kang Y, Gore J (1984) Studies of tissue NMR relaxation enhancement by manganese: dose and time dependences. Investigative Radiology 19 (5):399–407 [DOI] [PubMed] [Google Scholar]
  • 26.London RE, Toney G, Gabel SA, Funk A (1989) Magnetic resonance imaging studies of the brains of anesthetized rats treated with manganese chloride. Brain Research Bulletin 23 (3):229–235. [DOI] [PubMed] [Google Scholar]
  • 27.Lin Y-J, Koretsky AP (1997) Manganese ion enhances T1-weighted MRI during brain activation: An approach to direct imaging of brain function. Magnetic Resonance in Medicine 38 (3):378–388. [DOI] [PubMed] [Google Scholar]
  • 28.Pautler RG, Silva AC, Koretsky AP (1998) In vivo neuronal tract tracing using manganese-enhanced magnetic resonance imaging. Magnetic Resonance in Medicine 40 (5):740–748. [DOI] [PubMed] [Google Scholar]
  • 29.Smith KDB, Peethumnongsin E, Lin H, Zheng H, Pautler RG (2010) Increased Human Wildtype Tau Attenuates Axonal Transport Deficits Caused by Loss of APP in Mouse Models. Magnetic resonance insights 4:11–18. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Smith KDB, Paylor R, Pautler RG (2011) R-Flurbiprofen Improves Axonal Transport in the Tg2576 Mouse Model of Alzheimer’s Disease as Determined by MEMRI. Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine 65 (5):1423–1429. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Cross DJ, Flexman JA, Anzai Y, Morrow TJ, Maravilla KR, Minoshima S (2006) In vivo imaging of functional disruption, recovery and alteration in rat olfactory circuitry after lesion. NeuroImage 32 (3):1265–1272. [DOI] [PubMed] [Google Scholar]
  • 32.Cross DJ, Flexman JA, Anzai Y, Maravilla KR, Minoshima S (2008) Age-related decrease in axonal transport measured by MR imaging in vivo. NeuroImage 39 (3):915–926. [DOI] [PubMed] [Google Scholar]
  • 33.Bertrand A, Hoang DM, Khan U, Wadghiri YZ (2011) From Axonal Transport to Mitochondrial Trafficking: What Can We Learn from Manganese-Enhanced MRI Studies in Mouse Models of Alzheimer’s Disease? Current Medical Imaging Reviews 7 (2):16–27 [Google Scholar]
  • 34.Kim J, Choi I-Y, Michaelis ML, Lee P (2011) Quantitative in vivo measurement of early axonal transport deficits in a triple transgenic mouse model of Alzheimer’s disease using manganese-enhanced MRI. NeuroImage 56 (3):1286–1292. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Gallagher JJ, Zhang X, Ziomek GJ, Jacobs RE, Bearer EL (2012) Deficits in axonal transport in hippocampal-based circuitry and the visual pathway in APP knock-out animals witnessed by manganese enhanced MRI. NeuroImage 60 (3):1856–1866. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Bertrand A, Khan U, Hoang DM, Novikov DS, Krishnamurthy P, Rajamohamed Sait HB, Little BW, Sigurdsson EM, Wadghiri YZ (2013) Non-invasive, in vivo monitoring of neuronal transport impairment in a mouse model of tauopathy using MEMRI. NeuroImage 64 (Supplement C):693–702. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Bertrand A, Khan U, Hoang DM, Novikov D, Hill LK, Little BW, Sait HR, Shamsie M, Wadghiri YZ, Sigurdsson EM (2011) Aging diminishes neuronal transport in wild-type mice, but not in an accelerated mouse model of Aβ amyloidosis. Alzheimer’s & Dementia 7(4):S306. [Google Scholar]
  • 38.Little BW, Khan U, Bertrand A, Rajamohamedsait H, Hill LK, Hoang DM, Wadghiri YZ, Sigurdsson EM (2012). Tau immunotherapy improves axonal transport as detected in vivo by manganese-enhanced magnetic resonance imaging. Alzheimer’s & Dementia 8(4):P166. [Google Scholar]
  • 39.Baron MF, Rajamohamed Sait HB, RajaMohamed Sait WJ, Hoang DM, Sigurdsson EM, Wadghiri YZ, (2016). Antibody Therapy Against Tau Pathology Improves Neuronal Transport as Assessed In Vivo by Tract-Tracing Manganese-Enhanced MRI, Proceedings Sci. Meeting, Int’l Society for Magnetic Resonance in Medicine (Singapore) 24:6340. [Google Scholar]
  • 40.Wang F-H, Appelkvist P, Klason T, Gissberg O, Bogstedt A, Eliason K, Martinsson S, Briem S, Andersson A, Visser SAG, Ivarsson M, Lindberg M, Agerman K, Sandin J (2012) Decreased axonal transport rates in the Tg2576 APP transgenic mouse: improvement with the gamma-secretase inhibitor MRK-560 as detected by manganese-enhanced MRI. European Journal of Neuroscience 36 (9):3165–3172. [DOI] [PubMed] [Google Scholar]
  • 41.Daoust A, Bohic S, Saoudi Y, Debacker C, Gory-Fauré S, Andrieux A, Barbier EL, Deloulme J-C (2014) Neuronal transport defects of the MAP6 KO mouse – a model of schizophrenia – and alleviation by Epothilone D treatment, as observed using MEMRI. NeuroImage 96 (Supplement C) :133–142. [DOI] [PubMed] [Google Scholar]
  • 42.Majid T, Ali YO, Venkitaramani DV, Jang M-K, Lu H-C, Pautler RG (2014) In vivo axonal transport deficits in a mouse model of fronto-temporal dementia. NeuroImage: Clinical 4 (Supplement C):711–717. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Jouroukhin Y, Ostritsky R, Assaf Y, Pelled G, Giladi E, Gozes I (2013) NAP (davunetide) modifies disease progression in a mouse model of severe neurodegeneration: Protection against impairments in axonal transport. Neurobiology of Disease 56:79–94. [DOI] [PubMed] [Google Scholar]
  • 44.Neelavalli J, Haacke EM (2007) A simplified formula for T1 contrast optimization for short-TR steady-state incoherent (spoiled) gradient echo sequences. Magn Reson Imaging 25(10):1397–401 [DOI] [PubMed] [Google Scholar]
  • 45.Wadghiri YZ, Hoang DM, Wisniewski T, Sigurdsson EM (2012) In vivo Brain MR imaging of amyloid plaques in transgenic mice. Amyloid Proteins, Methods in Molecular Biology Series 2nd edition, vol.849:435–51. [Google Scholar]
  • 46.Buxton RB, Edelman RR, Rosen BR, Wismer GL, Brady TJ (1987) Contrast in rapid MR imaging: T1- and T2-weighted imaging. J Computed Assisted Tomography 11(1):7–16. [DOI] [PubMed] [Google Scholar]
  • 47.Ernst RR, Anderson WA (1966) Application of Fourier transform spectroscopy to magnetic resonance. Rev Sci Instrum 37:93–102. [Google Scholar]

RESOURCES