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Page 2

Example of a behavioral test battery to determine developmental milestones

Developmental milestoneDescription of test
Somatic growth
 Body weightPups are weighed daily
 Eyelid openingScored 0–3 (not open–fully open)
 Ear openingScored 0–3 (not open–fully open)
 Incisor eruptionScored 0–3 (not open–fully open)
Sensorimotor reflexes*
 Righting reflex
  Forelimb placingWhen the dorsum of the foot is contacted against the edge of an object, the foot is raised and placed on the surface.
  Fore and hind limb graspingWhen the underside of the forefoot is stroked with a toothpick, the foot reflexes to grab the object.
  Screen climbingWhen the pup is placed on a flat screen and allowed to grip and the screen is then turned to a 90° angle, the mouse climbs upward.
 Vibrissa placingWhen a cotton swab is stroked across the mouse's vibrissa (whiskers) it places its paw on the cotton swab.
 Cliff aversionWhen the pup is placed at the edge of a cliff or tabletop with forepaws and face over the edge, it turns and crawls away from the edge.
 Auditory startle responseWhen a loud clap of the hands occurs less than 10 cm away, the pup shows a whole body startle response.
 Tactile stimulationWhen von Frey hairs of 0.05 (weak) or 0.35 g (strong) are applied to the perioral area on each side of the head, the head should turn in that direction.
 Ultrasonic vocalizationThe pup is placed in a sound-attenuating chamber. Vocalizations are captured with a microphone, filtered, amplified, and recorded. The number of ultrasonic calls is analysed.
Homing testA litter of pups is placed in an incubator for 30 min. They are individually placed into a plastic viewing arena with wood shavings and nesting material in one corner demarcated with tape. Time for the pup to reach the goal area is recorded in seconds.