Biology Reference
In-Depth Information
6.8.2. Active Avoidance
The active avoidance test has been used in rats, mice, pigs, dogs,
and cats to evaluate learning/memory to avoid noxious stimulus.
In rodents, it can be conducted in either a two-compartment
apparatus, where the animal is required to cross to the adjoining
chamber to escape shock, or in a single chamber with a single verti-
cal pole that the mouse can jump onto when shock is administered.
The animal learns to avoid shock based on the presentation of a
light or other cue. In a unidirectional variant of the test, the animal
is always shocked in the same compartment. In the bidirectional
variant, the animal learns to monitor for cues in both compartments
to predict shock.
Escape/avoidance latencies and percentage of failures are the
measures (mice (
92, 97, 126
); rats (
52, 127, 128
); pigs (
120
);
dogs (
129
); and cats (
130, 131
)).
Fasted animals are rewarded with various treats if they choose the
same or a different cue, one of the two, or more depending on the
test, that they had a chance to examine before the test. Depending
on the test, various delays may be introduced before or between
cues. Typical tests include delayed matching-to-sample test
(DMTS), DNMS, delayed matching-to-position test (DMTP),
and delayed nonmatching to-position test (DNMP). Rats, mice,
dogs, cats, pigs, and monkeys can be subjects for these tests.
Rodents are typically tested in a variety of operant chambers or
in Y-maze (
108, 132, 133
). Wisconsin General Test Apparatus or
WGTA, National Center for Toxicological Research (NCTR)
Operant Test Battery (OTB) and various types of touch-screen
computer-based systems, e.g., Cambridge Neuropsychological
Test Automated Battery (CANTAB), are used for monkeys.
The percentage of errors and latency to make a choice (or to
err) are measured. Matching/nonmatching tasks are used to
assess working memory, short-term memory, visual-spatial learn-
ing/memory, object recognition, and problem solving (mice
(
108, 126, 134
); rats (
52, 135-137
); pigs (
109
); cats (
138
); dogs
(
139-141
); and monkeys (
142-147
)).
6.8.3. Matching/
Nonmatching Tasks
Displacement
Here, the animal observes placement of a nonfood object (e.g., a
toy) in one of the two bins and is then ordered to retrieve the
object. Various delays, placement of a bin with an object on a rotat-
ing beam followed by 90° rotation of the beam, and placement of
a screen between the animal and the rotating beam or darkness
may be introduced between demonstration of the object and the
command to retrieve it.
The test has been conducted in dogs and cats to assess working
memory and cognition. The percentage of errors serves as a mea-
sure for this test (
148, 149
).
6.8.4. Other Memory Tests
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