Amphetamine increases aversive conditioning to diffuse contextual stimuli and to a discrete trace stimulus when conditioned at higher footshock intensity

Norman, Christine; Cassaday, Helen J.

doi:10.1177/0269881103017001701

Cited by 36 publications

(54 citation statements)

References 40 publications

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“…It appears that amphetamine has a preference to enhance associative conditioning to a less salient stimulus over to a more salient stimulus. This particular finding is similar to that of Norman and Cassaday (2003), who showed that amphetamine selectively enhanced associative processing of less salient stimuli (trace CS, contextual cues, etc.) in a Pavlovian fear conditioning paradigm.…”

Section: Methodssupporting

confidence: 86%

“…Amphetamine has thus been extensively used in the preclinical studies of neurobiological mechanisms and behavioral characteristics of schizophrenia (Castner et al 2005;Robinson and Becker 1986). Recent approaches to modeling psychosis have been focusing on the information processing deficits that are thought to underlie the development of psychotic symptoms (Norman and Cassaday 2003;O'Tuathaigh et al 2003;Swerdlow et al 2000;Weiner 2003). Current research has emphasized the deficits in the attention domain (Buchanan et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Amphetamine selectively enhances avoidance responding to a less salient stimulus in rats

Munro

2008

J Neural Transm

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Although many studies have clearly demonstrated that amphetamine-induced attention deficits are useful in capturing some aspects of cognitive deficits of schizophrenia, it is still not clear how these deficits give rise to positive symptoms, such as delusional thoughts and hallucinations.While in an acute psychotic state, schizophrenic patients seem to have a heightened ability to process information coming from trivial stimuli in their internal or external environment and show stronger cognitive and motivational responses toward them, of which normal people would not notice (Gray 1998;Hemsley 1993;Jones et al. 1991;Kapur 2003). This enhanced ability to respond to less salient environmental stimuli has been argued cogently as one important mechanism underlying psychosis (Beninger 2006;Kapur 2003). In the present study, we attempted to directly model this psychological process (e.g., enhanced associative conditioning to a less salient stimulus) and investigated how repeated amphetamine treatment would impact this process in rats. We used a modified two-way (shuttle) avoidance-conditioning task involving two types of conditioned stimuli (CS1 and CS2) that varied in their salience and ability to predict the occurrence of the unconditioned stsimulus (US, foot-shock). We found that amphetamine (1.5 mg/kg, i.p.) selectively enhanced avoidance responding to the less salient CS2. Interestingly, amphetamine did not enhance avoidance responding to the more salient CS1. This effect of amphetamine may explain the psychological mechanisms underlying amphetamine psychosis and psychosis in schizophrenia.Abstract This preclinical study examined the psychological processes affected by amphetamine that contribute to human psychosis. Using a novel avoidance conditioning paradigm involving two conditioned stimuli (CS) with varied salience, we found that acute amphetamine (1.5 mg/ kg, i.p.) selectively enhanced avoidance responding to a less salient stimulus, but not to a salient one. These findings suggest that elevated dopaminergic activity selectively enhances the attributions of motivational salience to a less salient stimulus, a process that may bear relevance to the development of human delusional thoughts.

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Section: Methodssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Amphetamine selectively enhances avoidance responding to a less salient stimulus in rats

Munro

2008

J Neural Transm

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“…Finally, we sought to evaluate whether two dopamine agonists (D-amphetamine and methamphetamine), at moderate doses, might serve as potential cognitive enhancers (e.g., Grilly 2000; Grilly and Gowans 1988;Grilly et al 1989;Norman and Cassaday 2003;Sagvolden and Xu 2008). These two compounds also allowed us to evaluate the secondary hypothesis that interval timing is mediated by a dopamine-driven internal clock.…”

Section: Introductionmentioning

confidence: 99%

Pharmacological manipulations of interval timing using the peak procedure in male C3H mice

et al. 2008

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“…This finding of reduced conditioning contrasts with the heightened conditioning that can be seen to a trace CS in an analogous aversive procedure (Norman and Cassaday, 2003). Appetitive and aversive stimuli interact differently with the dopamine system (Di Chiara et al, 1999) and it was difficult to assess the implication of the aversive conditioning results for trace conditioning in an appetitive procedure.…”

Section: Conditioning To the Trace And Contiguous Csmentioning

confidence: 96%

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

2004

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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.

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Amphetamine increases aversive conditioning to diffuse contextual stimuli and to a discrete trace stimulus when conditioned at higher footshock intensity

Cited by 36 publications

References 40 publications

Amphetamine selectively enhances avoidance responding to a less salient stimulus in rats

Amphetamine selectively enhances avoidance responding to a less salient stimulus in rats

Pharmacological manipulations of interval timing using the peak procedure in male C3H mice

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

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