2.2 Group sizes
The current experiment followed the rules for replacement, refinement,
and reduction. Efforts were made to minimise suffering and reduce the
number of animals used in the present study. The sample sizes were
determined based on previous experience and reports of PCP-induced
cognitive deficits in conditioned response tests
(J. David Jentsch & Taylor, 2001). In
total, 64 rats were randomly divided into four groups. The drug
treatment regimen and the experimental protocol are shown in Figure 1.
We used 32 rats for the Morris water maze test (n=8 per group) and 32
rats for the fear conditioning test (n=8 per group). Two rats were
excluded because they died on the first and fourth days of PCP
treatment, respectively.