Jhr. Maes et al., Effects of acute D-amphetamine and ketamine on the performance of rats in a serial negative patterning procedure, BEHAV PHARM, 12(1), 2001, pp. 53-60
This study assessed the effects of acute amphetamine and ketamine on the pe
rformance of rats in a serial negative patterning procedure. A 5 s auditory
target stimulus and a 5 s visual feature cue were each followed by food, b
ut the target stimulus was not followed by food if preceded by the feature,
There was a 5 s empty gap between feature termination and target onset in
the latter, non-reinforced trials. Thus, the feature functioned as a cue si
gnalling the non-reinforcement of the target. The interval between the feat
ure and the target was varied in the non-reinforced trials following pretre
atment with subcutaneous saline, D-amphetamine (0.5 mg/kg) or ketamine (5 m
g/kg), The main behaviour measured was visits to the place of food delivery
during target presentation, Under saline, the response frequency during th
e target was lowest when the interval between the feature and the target ex
actly matched the interval used during training. Either shortening or lengt
hening the interval enhanced responding, Neither D-amphetamine nor ketamine
disturbed this temporal pattern, although D-amphetamine and ketamine non-s
pecifically increased and decreased response frequencies, respectively, in
all the trial types. The results are discussed in the framework of the amph
etamine and ketamine models of schizophrenia. (C) 2001 Lippincott Williams
& Wilkins.