Amphetamine decreases the expression and acquisition of appetitive conditioning but increases the acquisition of anticipatory responding over a trace interval

Abstract

The effects of amphetamine on selective learning were tested in a trace conditioning procedure, in which the informativeness of the conditioned stimulus (CS) (noise) was manipulated through the introduction of a time interval before the delivery of the unconditioned stimulus (UCS) (food). The results showed that d-amphetamine (0.5 and 1.5 mg/kg) impaired both the expression (Experiment 1b) and acquisition (Experiment 2) of appetitive conditioning. This was true for both trace and contiguously conditioned groups. The effects of the 0.5 mg/kg dose of d-amphetamine were not attributable to general motor (measured pre-CS) or motivational (measured post-UCS) effects of the drug. Moreover, the same pattern of effects (impaired appetitive conditioning, irrespective of the trace interval between CS and UCS) was confirmed in drug-free extinction tests. By contrast to the general depression in the acquisition and expression of associative learning observed under amphetamine, the 0.5 mg/kg dose promoted the acquisition of anticipatory responses made later in the trace interval (in Experiment 2 but, again, not the expression of previous conditioning in Experiment 1b). This suggests a dissociable effect of low-dose d-amphetamine on learning about the temporal relationship between CS and UCS.

Infusions of scopolamine in dorsal hippocampus reduce anticipatory responding in an appetitive trace conditioning procedure

“…After 5 days' acquisition at 10 trials/day, there were no significant effects of bins (Cassaday, Finger, & Horsley, 2008). However, effects of bins (moderated by systemic drug treatments) were seen when conditioning was conducted over 10 days' acquisition at 10 trials/day (Cassaday et al, 2008;Kantini, Norman, & Cassaday, 2004). Subsequent microinfusion studies have used a more intensive conditioning schedule identical to that adopted in the present study (conducted over 4 days, each of 30 trials, in order to limit the number of microinfusion sessions ;Pezze et al, , 2017.…”

From attention to memory along the dorsal-ventral axis of the medial prefrontal cortex: some methodological considerations

“…However, particularly in the case of trace conditioning, an additional consideration arises in that lesion effects have typically been investigated in aversively motivated procedures (eye blink or CER). Lesions and drug treatments affecting the DA system have been found to have different effects in aversive (Norman and Cassaday, 2003; Horsley and Cassaday, 2007) and appetitive trace conditioning procedures (Kantini et al, 2004; Cassaday et al, 2005). This difference may relate to the different motivational systems engaged by aversive and appetitive conditioning procedures or inevitable differences in the salience of the aversive and appetitive UCSs used in such studies.…”