Knowledge Base

Run Statistics

Procedure

1. Do one of the following:
   • Choose Analyze > View Run Statistics.
   • In the Experiment Explorer, right-click a trial/run and select View Run Statistics. This option is only available when the trial contains one or more (partially) classified runs.
2. If you want to see the Run Statistics of another trial or run, under Trial & Run Selection, select a trial and a run, or click the Previous/Next button to navigate to that trial and run.
3. Under Statistics, click on one of the tabs to view the corresponding parameter sheet and their statistics. All tabs and their parameters are described below.

Notes

• All sheets contain calibrated values, displayed in the Distance Unit selected in the Preferences.
• By right-clicking individual sheets you can either copy them to the clipboard or export them to Excel.
• You can export statistics of separate runs (Run Statistics), grouped per trial (Trial Statistics) and grouped per experimental group (Group Statistics).
• Paw prints displayed in gray are excluded from analysis based on the settings in the Data Segmentation profile currently active. To include all paw prints in the analysis, select the All Data Segmentation profile.

Summary

The Summary sheet shows a summary for the following parameter categories:

• Paw Statistics – The mean and standard deviation (SD) are given for each paw, for the girdle paws (RF-LF and RH-LH) and for the ratio of the girdle paws (RF/LF, LF/RF, RH/LH and LH/RH). See the Paw Statistics sheet for more details.
• Step Sequence – The total duration of all runs and the total number of categorized footfall patterns are given. For each footfall pattern category the percentage of the total number of categorized footfall patterns is given. Finally, the Regularity Index is shown, based on all categorized footfall patterns. See the Step Sequence sheet for more details.
• Base of Support – These are the mean values for the front paws and the hind paws. See the Base of Support sheet for more details.
• Print Positions – These are the mean values for the right paws and the left paws. See the Print Positions sheet for more details.
• Support – These are the relative duration of contact with the glass plate of all paw combinations. See the Support sheet for more details.
• Phase Dispersions – The Mean, AD (Angular Deviation), SD (Circular Standard Deviation) and R for all pairs are given, together with the number of Mismatches and occurrences of Anchor-No-Target (ANT), Anchor-Multiple-Targets (AMT) and Target-No-Anchor (TNA). Note that the results are circular statistics. See the Phase Dispersions sheet for details.
• Couplings – The same statistics are given as for Phase Dispersions. See the Couplings sheet for more details.

General

The General sheet displays the following variables:

• Name – The name of the run.
• Start Time – The date and time the run was acquired.
• Run Duration – The duration of the recorded run.
• Run Average Speed – The average speed of the recorded run. This is the speed of the animal's body in the recorded run.
• Run Maximum Variation – The maximum variation in walking speed in the recorded run.
• Frame Rate – The frame rate of the camera. This is always 100 frames per second (fps).
• Camera Gain – The value of the Camera Gain from the Detection Settings.
• Green Intensity Threshold – The value of the Green Intensity Threshold from the Detection Settings.
• X-Unit (mm/pixel) – The horizontal size of a single pixel.
• Y-Unit (mm/pixel) – The vertical size of a single pixel.
• Walkway Length – The length of the defined walkway.
• Walkway Width – The width of the defined walkway.

Paw Statistics

The Paw Statistics sheet displays parameters that are based on individual paw prints. Choose Analyze > View Run Statistics and under Statistics click Paw Statistics.

Which paws and parameters are displayed in this sheet depends on the selection in the currently active Parameter profile (displayed in blue and bold in the Experiment Explorer).

In the Paw Statistics sheet, when you click one of the paw rows:

• The Print View highlights the corresponding print.
• The Timing View shows the corresponding Stand.
• The Sub Prints View shows the individual prints of the Stand.

Paw

The Paw label based on the current classification.

Initial Contact At (s)

Initial Contact At (s) is the time in seconds since the start of the run at which a paw makes contact with the glass plate.

Stand (s) / Stance (s)

Stand (s) or Stance phase is the duration in seconds of contact of a paw with the glass plate. Kloos et al. (2005) (Exp. Neurol. 191: 251-265) showed that rats with a moderate spinal cord injury showed an increase in stand duration of the hind legs compared to pre-operative values.

Stand Index

Stand Index is a measure for the speed at which the paw loses contact with the glass plate. The formula for Stand Index is:

Stand Index = (a / X0) × frame rate

Where:

• a is derived from y = ax + b, which describes a straight line fitted through the values of Print Area between the time of maximum contact and the 90th percentile of the stance duration. The value a should be interpreted as "change in print area per video frame."
• X0 is the maximum contact area.
• frame rate is the camera frame rate (usually 100 frames per second). This correction allows comparison of results obtained with different frame rates.

Stand Index is therefore a function of the change in print area per second. It is always negative because it describes the decrease in print area over time. The more negative the value, the steeper the slope of the line that describes the reduction in print area, meaning that the subject lifts its paw more quickly.

Notes

• Stand Index should only be used for smoothly moving animals.
• The formula of Stand Index includes a/X0 to correct for differences in Print Area between paws, subjects, etc.