He time (latency) mice spent on a rod rotating at 10 rpm for 2 minutes [20] and recorded the average from three trials. The DigiGait system was used for footprint analysis, in which the forelimb and hindlimb step widths (defined as the distance between the right and left footprint) were measuredMRI Findings of Paranodal Junction FailureFigure 1. Histological analyses of the Title Loaded From File Title Loaded From File spinal cords of WT and CST-KO mice. (A) Representative images of HE-stained axial spinal cord sections. (B) Quantitative analysis of the spinal cord areas of the HE-stained axial sections revealed no significant difference between WT and CST-KO mice. (C) Representative images of LFB-stained axial spinal cord sections. (D) Quantitative analysis of the ventral spinal cord areas measured in the LFB-stained axial sections revealed no significant difference between WT and CST-KO mice. (E) Representative EC-stained images of axially sectioned spinal cords. (F) Quantitative analysis of the ventral spinal cord areas measured in the EC-stained axial sections revealed no significant difference between WT and CST-KO mice. Scale bars: 500 mm in (A), (C), and (E). (B, D, F) Values show the means 6 s.d. (n = 4), and significant differences were determined by the Mann-Whitney test. doi:10.1371/journal.pone.0052904.gfor as long as the mice could walk with consistent weightsupporting steps on a treadmill set at a speed of 8 cm/s.ElectrophysiologyElectrophysiological experiments were conducted with an electromyography (EMG)/evoked potential measuring system (Neuropack S1 MEB-9400 series, Nihon Kohden, Tokyo, Japan). WT and CST-KO mice were anesthetized with an i.p. injection ofketamine (40 mg/kg) and xylazine (4 mg/kg), as previously described [21]. An electrode was inserted into the spinal cord at the occipito-cervical area to induce a motor-evoked potential (MEP). The potential was recorded by two needle electrodes, one in each hindlimb; the active electrode was placed in the muscle belly of each limb, and the reference electrode was placed near the distal tendon of the muscle. The ground electrode was placed subcutaneously between the coil and the recording electrodes. ToMRI Findings of Paranodal Junction FailureFigure 2. Magnetic resonance images of the spinal cords of WT and CST-KO 24195657 mice. (A) T1 measurement. The T1 time in the major white matter tracts within the ventral regions was significantly lower in CST-KO mice than in WT mice (circled in panel C), both ex and in vivo. (B) T2 measurement. The T2 time was significantly higher in CST-KO mice than in WT mice, both ex and in vivo. (C) Representative axial images of ex vivo and in vivo T2WI in WT and CST-KO mice. (D) Representative sagittal images of in vivo T2WI in WT and CST-KO mice. Scale bars: 5 mm. (A, B) Values shown are means 6 s.d. (ex vivo: n = 6, in vivo: n = 6), with statistical significance determined by the unpaired t-test. *: p,0.05. doi:10.1371/journal.pone.0052904.ginduce MEPs, a 0.4-mA stimulus was applied at the electrode; the pulse duration in all experiments was 0.2 ms. The onset latency was measured as the time in milliseconds between the stimulus and the onset of the first wave. Ten responses were averaged and sorted for off-line analysis [22].Results Histological analyses of the WT and CST-KO spinal cordHistological analyses of the anatomical spinal cord structure in WT and CST-KO mice were performed using HE, LFB, and EC staining. In these analyses, the spinal cords of WT and CST-KO mice were identical in.He time (latency) mice spent on a rod rotating at 10 rpm for 2 minutes [20] and recorded the average from three trials. The DigiGait system was used for footprint analysis, in which the forelimb and hindlimb step widths (defined as the distance between the right and left footprint) were measuredMRI Findings of Paranodal Junction FailureFigure 1. Histological analyses of the spinal cords of WT and CST-KO mice. (A) Representative images of HE-stained axial spinal cord sections. (B) Quantitative analysis of the spinal cord areas of the HE-stained axial sections revealed no significant difference between WT and CST-KO mice. (C) Representative images of LFB-stained axial spinal cord sections. (D) Quantitative analysis of the ventral spinal cord areas measured in the LFB-stained axial sections revealed no significant difference between WT and CST-KO mice. (E) Representative EC-stained images of axially sectioned spinal cords. (F) Quantitative analysis of the ventral spinal cord areas measured in the EC-stained axial sections revealed no significant difference between WT and CST-KO mice. Scale bars: 500 mm in (A), (C), and (E). (B, D, F) Values show the means 6 s.d. (n = 4), and significant differences were determined by the Mann-Whitney test. doi:10.1371/journal.pone.0052904.gfor as long as the mice could walk with consistent weightsupporting steps on a treadmill set at a speed of 8 cm/s.ElectrophysiologyElectrophysiological experiments were conducted with an electromyography (EMG)/evoked potential measuring system (Neuropack S1 MEB-9400 series, Nihon Kohden, Tokyo, Japan). WT and CST-KO mice were anesthetized with an i.p. injection ofketamine (40 mg/kg) and xylazine (4 mg/kg), as previously described [21]. An electrode was inserted into the spinal cord at the occipito-cervical area to induce a motor-evoked potential (MEP). The potential was recorded by two needle electrodes, one in each hindlimb; the active electrode was placed in the muscle belly of each limb, and the reference electrode was placed near the distal tendon of the muscle. The ground electrode was placed subcutaneously between the coil and the recording electrodes. ToMRI Findings of Paranodal Junction FailureFigure 2. Magnetic resonance images of the spinal cords of WT and CST-KO 24195657 mice. (A) T1 measurement. The T1 time in the major white matter tracts within the ventral regions was significantly lower in CST-KO mice than in WT mice (circled in panel C), both ex and in vivo. (B) T2 measurement. The T2 time was significantly higher in CST-KO mice than in WT mice, both ex and in vivo. (C) Representative axial images of ex vivo and in vivo T2WI in WT and CST-KO mice. (D) Representative sagittal images of in vivo T2WI in WT and CST-KO mice. Scale bars: 5 mm. (A, B) Values shown are means 6 s.d. (ex vivo: n = 6, in vivo: n = 6), with statistical significance determined by the unpaired t-test. *: p,0.05. doi:10.1371/journal.pone.0052904.ginduce MEPs, a 0.4-mA stimulus was applied at the electrode; the pulse duration in all experiments was 0.2 ms. The onset latency was measured as the time in milliseconds between the stimulus and the onset of the first wave. Ten responses were averaged and sorted for off-line analysis [22].Results Histological analyses of the WT and CST-KO spinal cordHistological analyses of the anatomical spinal cord structure in WT and CST-KO mice were performed using HE, LFB, and EC staining. In these analyses, the spinal cords of WT and CST-KO mice were identical in.
