Table 2

Ladder-run foot scoring scale

Score	Metz scale2009	Explanation
0	Total miss	0 points were assigned when the limb completely missed a rung (i.e. it did not touch it), and a fall occurred. Afall was defined as a limb deeply falling in between rungs with body posture and balance being disturbed.
1	Deep slip	The limb was initially placed on a rung, then slipped off as the mouse began to bear weight, causing theanimal to fall.
2	Slight slip	The limb was placed on a rung, then slipped off as the mouse began to bear weight, but it did not resultin a fall or interrupt the step cycle. In this case, the animal was able to maintain balance and continuea coordinated gait.
3	Replacement	The limb was placed on a rung, but before it was bearing weight it was quickly lifted and placed onanother rung.
4	Correction	The limb was aimed for one rung but was then placed on another rung without touching the first one.Alternatively, a score of 4 was recorded if a limb was placed on a rung and was quickly repositionedwhile remaining on the same rung.
5	Partialplacement	The limb was placed on a rung with either wrist or digits of the forelimb or heel or toes of the hindlimb.
6	Correctplacement	The midplantar surface of a limb was placed on the rung with full weight support.

This 6 point scale was used to score the mouse hindlimb positioning when crossing over the ladder-run test, 0 being the complete miss of the hindpaw placement on the ladder rung, up to a maximum score of six with correct paw placement achieved. This scale was used throughout the experiments and was adapted from Metz and Whishaw (2009).