Assessment of Cognitive and Sensorimotor Defi cits - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 237

Variables measured . Latency to immobility (defi ned as a
lack of escape-related movements) and percent time immo-
bile during a 6-min duration.

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● Data interpretation . This test is based on the principle that
rats subjected to the short-term stress of an inescapable
cylinder of water will alternate between periods of strug-
gling to escape and immobility. A quicker latency to immo-
bility and higher percentage of time spent immobile
suggest “behavioral despair,” or depression-like behavior.
2. Tail suspension

Procedure . If using a video camera to assist with offl ine
scoring, start the recording. Mice are suspended by the tail
with adhesive tape attached ~1 cm from the tip. The other
end of the tape is wrapped around the hook in the ceiling
of the box and the stopwatch is started.

●

Variables measured . Latency to immobility and percent
time immobile (defi ned as a complete lack of movement
on the part of the mouse) during a 6-min duration.

●

Data interpretation . This test is based on the principle that
mice subjected to the short-term stress of tail suspension
will alternate between periods of struggle and immobility.
Quicker latency to immobility and higher percentage of
time spent immobile suggest “behavioral despair,” or
depression-like behavior.

●

3.6. Day 6 (See Note 6):
Water Maze—Cued

1. Procedure . The pool is fi lled the day before to allow the water
to adjust to room temperature (~20-22°C). The holding cage
and heating lamp are set up away from the pool of water. The
depth of the water is adjusted so that the surface of the escape
platform is visible 1-2 cm above the surface of the water. The
platform is placed in the middle of one of four predetermined
quadrants of the pool, and the video recording is started. For
each trial, an animal is released, nose against the wall, into the
pool opposite the location of the platform for that trial. All tri-
als last a maximum of 60 s, at which point the animal is manu-
ally guided to the platform, where it is allowed to remain for
15 s. During this period, the sieve is used to remove feces from
the pool. The animals are given ten trials in fi ve blocks of two
consecutive trials with a ~10 min inter-block interval. After
each block of two trials, the animal is removed from the pool
and placed into the holding cage under the heat lamp, where it
dries off before being put back into its home cage. The location
of the platform changes for each block of trials.
2. Variables measured . Total swim distance, latency to fi nd the
platform, and swim speed. Use of a computerized tracking sys-
tem allows for more sophisticated measures, such as proximity
to target and left/right turn bias.