ABSTRACT
The retention of a weak conditioned saccharin aversion was tested using independent groups over a 14-day period. The delay between CS (saccharin 0.1 %) and US (LiCl 0.15 M) was 6 hours. Significant variations in the retention function were observed, in particular an improvement of memory - i.e. an incubation effect - over the 14-day period. This result suggests that retention of conditioned taste aversion may share common features with the retention of more classical aversive conditioning.
ABSTRACT
Rats were first trained to press a bar for water reinforcement. The day after reaching criterion, the animals received a subcutaneous injection of cycloheximide (CXM-2.5 mg/kg) or saline, 15 minutes before a single punishment (P) session where bar pressing was followed by a strong inescapable footshock (CXM-P and saline-P groups). No punishment was given to control groups (CXM-NP and saline-NP groups). Retention for this learning experience was tested 24 hr, one week or two weeks later. Performances of the control groups were similar at the three retention intervals although some CXM-induced aversion appeared at 24 hr. The saline-P groups always demonstrated good retention of prior aversive experience. By contrast, a long-lasting CXM-induced amnesia was apparent among the CXM-P groups. This deficit is not easily explained by nonspecific effects of the drug such as altered motor activity or motivational changes. Moreover, CXM-induced amnesia seems to be the result of impaired memory formation rather than impaired memory retrieval.
