Open field activity
(Gently place each animal in the center of a field and make the following 10 observations for 3 minutes. If an animal fails to move during the 3-minute observation period, lightly prod it in the open field after observations are complete to check for loss of movement, recording observations.)

1) Number of rearings: Count with a counter the number of times the animal completely removes its forelimbs from the floor and the number of times it supports itself on a wall during the 3 minutes (counted).

2) Clonic involuntary movement: Choose the applicable item from the following list (scored).

1: None/normal
2: Repetitive mouth/jaw motion
3: Twitching of limbs, auricles, or head
4: Generalized tremors
5: Clonic seizure
6: Trembling

3) Tonic involuntary movement: Choose the applicable item from the following list (scored).

1: None/normal
2: Extending contraction (limb or limbs extends and becomes rigid)
3: Sudden jumping (all limbs come off floor)
4: Tonic extending convulsion
5: Tonic convulsions seen with respiratory distress, seizure, or death

4) Gait: Choose the item from the following list that best describes the animal's gait (classification).

N (normal): Head is horizontal, abdomen rises slightly above floor, and body moves up and down slightly during walking
D (drag): Animal drags body, abdomen touches floor, and body wobbles
H (hindlimbs exaggerated): Animal spreads or drags hindlimbs, unable to support weight of body
HU (hunched): Back is rounded or animal crouches
T (tiptoes): Animal walks on tiptoes
A (ataxia): Loss of motor coordination, excess swaying , animal lurches and sways when walking

5) Movements: Choose the item from the following list that best describes the animal's movement, disregarding gait. Also consider decreases in movement over time (scored).

1: Highly decreased
2: Slightly decreased
3: Normal
4: Slightly increased
5: Highly increased

6) Arousal: Choose the item from the following list that best describes the animal's activity. Also consider decrease in activity over time (scored).

1: Highly decreased (paralyzed; coma)
2: Moderately decreased (mildly numb; only moves head)
3: Slightly decreased (sometimes does not move but engages in exploratory activity)
4: Normal (keeps guard up and engages in exploratory activity)
5: Slightly increased (mildly excited or tense; sudden lurches forward and stillness)
6: Highly increased (highly alert; runs or moves body suddenly)

7) Occurrence of stereotype: Check for turning around, stereotypical preening, squeaking, shaking head, and other repetitive and stereotypical behavior (findings).
Enter a minus sign (-) in the findings column if no such behavior is observed.

8) Abnormal behavior: Check for abnormal behavior (e.g., squirming, running backwards, labored movement, squealing), disregarding stereotypical activity  (findings).
Enter a minus sign (-) in the findings column if no such behavior is observed.

9) Number of defecations: Count the number of feces defecated on the open field during the 3 minute observation period. Replace the paper liner after observations if it is dirty (counted).

10) Number of urinations: Count the number of urine stains on the open field left during the 3 minute observation period. A stain left by a rat moving while urinating shall be considered 1 stain. Replace the paper liner after observations if it is dirty (counted).