The effects of LiCl preexposure on amphetamine-induced taste aversions: An assessment of blocking

Enhancement of conditioned preference for a place paired with amphetamine produced by blocking the association between place and amphetamine-induced sickness

“…An important difference in procedure that may underly the discrepancy between the present results and those of Ford and Riley (1984) or of Parker (1986) is that blocking of conditioned place aversion, as measured by enhancement of CPP, was studied in the present experiments rather than blocking of conditioned taste aversion. Conditioned place aversions are usually considered to represent a weaker learning process than conditioned taste aversions and hence may be more susceptible to disruption (Parker 1986).…”

“…However, blocking is not always obtained when the US drug is changed from lithium in Phase 1 to amphetamine in Phase 2. Ford and Riley (1984) found evidence for cross-tolerance to the aversive effect of amphetamine after place-lithium pairings but not for blocking. That is, attenuation of the conditioned taste aversion (CTA) occurred in Phase 2 whether or not the amphetamine was signalled by the place CS.…”

“…The presence of a coffee CS previously associated with lithium in Phase 1 did not interfere with the conditioning of an aversion to saccharin with amphetamine in Phase 2. Since cross-tolerance between lithium and amphetamine (Ford and Riley 1984) implies that the CTA-inducing effects of the drugs are similar, failure to obtain such crossdrug blocking is surprising.…”

The Role of Injection Cues in the Associative Control of the US Pre-Exposure Effect in Flavour Aversion Learning

“…Although the US pre-exposure effect on aversion learning has often been thought to be associative in nature, several studies have shown that the US pre-exposure effect occurs when LiCl is signalled (Cannon et al, 1975;Riley, Jacobs, & LoLordo, 1976) and when preexposure and conditioning occur in different contexts, either using LiCl as US or using another injected substance like morphine or amphetamine (Cannon et al, 1975;Dacany & Riley, 1982;Domjan & Siegel, 1983;Ford & Riley, 1984;Rudy et al, 1977;Stewart & Eikelboom, 1978). These results seem inexplicable according to the contextual-blocking hypothesis and have been thought to provide evidence in favour of an interpretation in terms of the development of non-associative tolerance.…”

Unconditioned Stimulus Pre-exposure Interferes with Conditioned Taste Aversion in Rats

“…It has been shown that pre-exposure to CS alone or to US alone can interfere with the formation of CTA [for CS pre-exposure effect see 7, 22, 25, 44; for US pre-exposure effect see 2,3,4,6,8,12,14,16,18,21,22,31,41,42,43]. The pre-exposure to CS alone results in reduced associability between CS and US and the effect is known as latent inhibition.…”