Fig. 5. Food deprivation for 5 days inhibits conditioned taste aversion (CTA) memory formation. (A) The response to the conditioned stimulus (CS) in the pre- and post-test sessions following the one-trial conditioning procedure in snails deprived of food for 5 days. Memory was not formed as indicated by there being no significant difference between the pre-test and post-test response to the CS. (B) As in A, except that these snails received 10 paired backward-conditioning (CS–US) presentations. Again, long-term memory (LTM) was not observed even with this more intense conditioning. In both A and B 40 snails were used. No significant differences in the feeding response were found in either case (Student's t-test). All data are the means ± s.e.m. (N=40 each). These results show that 5 days of food deprivation alters the internal state of the snail in such a manner that memory for CTA cannot be formed.