Article Figures & Data
Figures
- Figure 1.
Scheme of experimental design. Depicted images were captured from the CatWalk video recordings providing information about the body silhouette and paw positions. The timeline displays the number of rodents and run videos analyzed within a longitudinal, repeated experimental design spanning five age points for rats and three age points for mice.
- Figure 2.
Scheme of image-flow analysis. a–j, Images captured from the unlabeled CatWalk videos (a, b); background images (c, d); background subtraction results IFG (e, f); binary largest objects IR (g, h); silhouette length illustration (i, j): rat with a silhouette length of 23.9 cm and mouse with a silhouette length of 9 cm.
- Figure 3.
Block diagram of the silhouette extraction, tail removal, and silhouette parameters.
- Figure 4.
Scatter plots for the correlation between nonscaled and scaled gait parameters with silhouette length in wild-type rodents. The numbers of animals and the number of run videos are given in Figure 1. The animal data are the averaging results from their respective CatWalk run data. r values, r 2 values, p values, and the regression line were calculated from the animal data.
- Figure 5.
a, Diagram of body length (nose-tip to tail-base) measurement. b, Scatter plot for correlation between body length and silhouette length of the small cohort of rats.
- Figure 6.
a, b, Scatter plots for correlation between body weight with silhouette length of wild-type animals: rats (a) and mice (b).
- Figure 7.
a–j, Genotype-related differences in unscaled and scaled hind stride length, unscaled and scaled hind swing speed, as well as silhouette length along with age: α-synuclein rat (a–e), BACHD mice (f–j). Each data point represents the mean ± SEM. p Values from multiple-comparison tests with Bonferroni correction: *p < 0.05, **p < 0.01, ***p < 0.001.
- Figure 8.
Differences between wild-type and transgenic animal models observed by their unscaled and scaled gait parameters individually by multiple-comparison tests and reported in heat maps (Timotius et al., 2018a, 2019).
Tables
- Table 1.
Sample Pearson correlation coefficients (r) and p values of the silhouette length and CatWalk gait parameters
Rats Mice Gait Nonscaled Scaled Nonscaled Scaled parameters r p r p r p r p Stride lengths Front-paw stride length 0.72 <0.0001 0.03 0.75 0.35 0.03 −0.07 0.69 Hind-paw stride length 0.72 <0.0001 0.02 0.81 0.35 0.03 −0.05 0.76 Parameters relating to duration Front-paw stand time 0.02 0.81 −0.34 <0.001 <0.01 0.97 −0.18 0.28 Front-paw swing time −0.20 0.05 −0.58 <0.0001 −0.12 0.48 −0.38 0.02 Front-paw step cycle −0.04 0.72 −0.45 <0.0001 −0.05 0.79 −0.27 0.10 Hind-paw stand time −0.05 0.59 −0.36 <0.001 <0.01 0.97 −0.16 0.33 Hind-paw swing time 0.07 0.51 −0.57 <0.0001 −0.10 0.56 −0.42 <0.01 Hind-paw step cycle −0.04 0.70 −0.46 <0.0001 −0.03 0.85 −0.26 0.12 Speed parameters Body speed 0.31 <0.01 (i) −0.06
(ii) 0.13(i) 0.54
(ii) 0.200.18 0.29 (i)<0.01
(ii) 0.09(i) 0.98
(ii) 0.58Front-paw swing speed 0.49 <0.0001 (i) 0.09
(ii) 0.31(i) 0.40
(ii)<0.010.22 0.18 (i) 0.02
(ii) 0.12(i) 0.90
(ii) 0.46Hind-paw swing speed 0.51 <0.0001 (i) −0.08
(ii) 0.25(i) 0.43
(ii) 0.010.30 0.07 (i) 0.04
(ii) 0.18(i) 0.80
(ii) 0.29The scaled parameters which show higher p values compared with their nonscaled versions are in bold. (i), Scaling method:
; (ii), scaling method:
.
- Table 2.
The effect of age on the silhouette and gait parameters: repeated-measures ANOVA (p values)
Rats Mice Parameters Nonscaled Scaled* Nonscaled Scaled* Stride lengths Front-paw stride length <0.001 0.69 0.13 0.20 Hind-paw stride length <0.0001 0.64 0.12 0.18 Speed parameters Body speed 0.11 0.24 0.11 0.15 Front-paw swing speed 0.03 0.35 0.04 0.07 Hind-paw swing speed 0.04 0.24 0.04 0.06 Silhouette parameters Silhouette length <0.0001 <0.01 Silhouette area without tail <0.0001 <0.001 Silhouette area with tail <0.0001 <0.001 *Scaling method
.
- Table 3.
Correlation between silhouette length, silhouette area (with tail), body weight, and age: p values, r values, and r 2 values
Silhouette length Silhouette area Body weight Age Rats Mice Rats Mice Rats Mice Rats Mice Silhouette length p =0
r = 1
r2 = 1Silhouette area p < 0.0001
r = 0.93
r2 = 0.87p < 0.0001
r = 0.84
r2 = 0.70p = 0
r = 1
r2 = 1Body weight p < 0.0001
r = 0.90
r2 = 0.81p < 0.0001
r = 0.75
r2 = 0.57p < 0.0001
r = 0.98
r2 = 0.96p < 0.0001
r = 0.89
r2 = 0.79p = 0
r = 1
r2 = 1Age p < 0.0001
r = 0.74
r2 = 0.55p < 0.01
r = 0.49
r2 = 0.24p < 0.0001
r = 0.88
r2 = 0.77p < 0.01
r = 0.50
r2 = 0.25p < 0.0001
r = 0.90
r2 = 0.81p < 0.0001
r = 0.61
r2 = 0.37p = 0
r = 1
r2 = 1 - Table 4.
r and p values of the silhouette area (asil) and CatWalk gait parameters (scaling method:
)
Rats Mice Gait Nonscaled Scaled Nonscaled Scaled parameters r p r p r p r p Stride lengths Front-paw stride length 0.59 <0.0001 −0.80 <0.0001 0.31 0.06 −0.37 0.02 Hind-paw stride length 0.59 <0.0001 −0.81 <0.0001 0.31 0.06 −0.35 0.03 Parameters relating to duration Front-paw stand time 0.06 0.57 −0.66 <0.0001 0.19 0.25 −0.14 0.41 Front-paw swing time −0.14 0.17 −0.80 <0.0001 <0.001 0.99 −0.45 <0.01 Front-paw step cycle 0.01 0.88 −0.74 <0.0001 0.11 0.49 −0.29 0.08 Hind-paw stand time <0.01 0.94 −0.62 <0.0001 0.15 0.37 −0.13 0.43 Hind-paw swing time 0.02 0.81 −0.88 <0.0001 0.06 0.71 −0.49 <0.01 Hind-paw step cycle <0.01 0.99 −0.76 <0.0001 0.13 0.44 −0.27 0.10 Speed parameters Body speed 0.27 0.02 −0.55 <0.0001 0.03 0.85 −0.24 0.15 Front-paw swing speed 0.38 <0.0001 −0.54 <0.0001 0.13 0.45 −0.20 0.22 Hind-paw swing speed 0.44 <0.0001 −0.72 <0.0001 0.15 0.36 −0.26 0.11 The scaled parameters that show higher p values compared with their nonscaled versions are in bold.
Rats Mice Gait Nonscaled Scaled Nonscaled Scaled parameters r p r p r p r p Stride lengths Front-paw stride length 0.54 <0.0001 −0.95 <0.0001 0.36 0.03 −0.69 <0.0001 Hind-paw stride length 0.54 <0.0001 −0.95 <0.0001 0.37 0.02 −0.67 <0.0001 Parameters relating to duration Front-paw stand time 0.04 0.70 −0.87 <0.0001 0.06 0.73 −0.47 <0.01 Front-paw swing time −0.11 0.35 −0.92 <0.0001 −0.01 0.95 −0.67 <0.0001 Front-paw step cycle 0.01 0.92 −0.90 <0.0001 0.02 0.88 −0.58 <0.001 Hind-paw stand time 0.01 0.91 −0.84 <0.0001 0.04 0.81 −0.42 <0.01 Hind-paw swing time −0.01 0.90 −0.95 <0.0001 0.02 0.88 −0.74 <0.0001 Hind-paw step cycle <0.01 0.98 −0.91 <0.0001 0.03 0.86 −0.57 <0.001 Speed parameters Body speed 0.20 0.08 −0.81 <0.0001 0.10 0.54 −0.39 0.02 Front-paw swing speed 0.32 <0.01 −0.83 <0.0001 0.14 0.39 −0.43 <0.01 Hind-paw swing speed 0.41 <0.001 −0.90 <0.0001 0.21 0.21 −0.50 <0.01 Rats Mice Gait Nonscaled Scaled Nonscaled Scaled parameters r p r p r p r p Stride lengths Front-paw stride length 0.55 <0.0001 −0.89 <0.0001 0.33 0.046 −0.93 <0.0001 Hind-paw stride length 0.57 <0.0001 −0.89 <0.0001 0.33 0.044 −0.93 <0.0001 Parameters relating to duration Front-paw stand time −0.05 0.62 −0.88 <0.0001 −0.24 0.14 −0.84 <0.0001 Front-paw swing time −0.14 0.16 −0.88 <0.0001 −0.33 0.04 −0.91 <0.0001 Front-paw step cycle −0.07 0.50 −0.89 <0.0001 −0.31 0.06 −0.89 <0.0001 Hind-paw stand time −0.08 0.44 −0.88 <0.0001 −0.21 0.20 −0.81 <0.0001 Hind-paw swing time 0.08 0.41 −0.89 <0.0001 −0.35 0.03 −0.93 <0.0001 Hind-paw step cycle −0.08 0.45 −0.89 <0.0001 −0.29 0.07 −0.88 <0.0001 Speed parameters Body speed 0.28 <0.01 −0.85 <0.0001 0.32 0.047 −0.74 <0.0001 Front-paw swing speed 0.36 <0.001 −0.86 <0.0001 0.38 0.02 −0.81 <0.0001 Hind-paw swing speed 0.37 <0.001 −0.88 <0.0001 0.44 <0.01 −0.87 <0.0001 - Table 7.
The effect of age, the genotype–age interaction and the effect of genotype on the silhouette parameters and gait parameters: mixed ANOVA and multiple-comparison tests with Bonferroni correction (p values with lower bound adjustment)
Rats Mice Parameters Age Interaction Genotype Age Interaction Genotype Stride lengths Front-paw stride length (cm) <0.0001 0.46 0.01 0.005 0.25 0.03 Hind-paw stride length (cm) <0.0001 0.54 <0.01 0.004 0.24 0.03 Scaled front-paw stride length* 0.60 0.58 0.046 0.013 0.17 0.90 Scaled hind-paw stride length* 0.53 0.67 0.02 0.01 0.17 0.94 Speed parameters Body speed (cm/s) 0.01 0.55 0.26 0.004 0.25 0.03 Front-paw swing speed (cm/s) <0.001 0.43 0.35 0.004 0.43 <0.01 Hind-paw swing speed (cm/s) <0.001 0.59 <0.01 0.003 0.47 <0.001 Scaled body speed (1/s)* 0.16 0.51 0.47 0.007 0.25 0.18 Scaled front-paw swing speed (1/s)* 0.13 0.41 0.65 0.007 0.45 0.11 Scaled hind-paw swing speed (1/s)* 0.11 0.60 0.01 0.007 0.47 <0.01 Body parameters Silhouette length (mm) <0.0001 0.23 0.03 0.012 0.10 <0.0001 Silhouette area without tail (mm2) <0.0001 0.15 <0.001 <0.001 0.26 <0.0001 Silhouette area with tail (mm2) <0.0001 0.26 <0.01 <0.01 0.14 <0.0001 Weight (g) <0.0001 0.20 0.03 <0.0001 0.35 <0.0001 Weight silhouette length index (g/cm2) <0.0001 0.17 0.29 <0.001 0.55 <0.001 ↵* Scaled based on the silhouette length (scaling method:
).
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