Sign-tracking (autoshaping) in rats: A comparison of cocaine and food as unconditioned stimuli

Abstract

A series of experiments was performed to determine whether sign-tracking would occur in rats with intravenous (i.v.) cocaine as the unconditioned stimulus. In Experiment 1, a retractable lever paired with food produced strong sign-tracking, but a lever paired with one of three doses of i.v. cocaine did not elicit any approach or contact behavior. Experiment 2 demonstrated that doses of cocaine that did not elicit sign-tracking would function as a positive reinforcer for a lever contact operant. In Experiment 3, an artificial consummatory response was added to make the cocaine reinforcement episode more behaviorally comparable to that occasioned by food. Although the rats readily performed this response when it was required to receive cocaine infusions, they still did not contact a lever that signaled the availability of these infusions. It appears that cocaine is different from other positive reinforcers (e.g., food, water, warmth, or intracranial stimulation) in that it will not produce sign-tracking in rats.

Individual differences in the attribution of incentive salience to reward-related cues: Implications for addiction

“…With repeated pairings of the lever and cocaine rats began to approach the lever more reliably and more rapidly, whereas rats that received pseudorandom (i.e., unpaired) CS-US presentations did not. These findings are in contrast to those reported by Kearns and Weiss (2004), and we speculate that these disparate results are due to methodological differences (for details see Uslaner et al, 2006). Kearns and Weiss (2004) used relatively short inter-trial intervals, with CS-US presentations occurring on average every 90 sec.…”

“…These findings are in contrast to those reported by Kearns and Weiss (2004), and we speculate that these disparate results are due to methodological differences (for details see Uslaner et al, 2006). Kearns and Weiss (2004) used relatively short inter-trial intervals, with CS-US presentations occurring on average every 90 sec. In contrast to food reward, neurobiological and interoceptive effects of cocaine persist for longer than 90 sec.…”

“…This idea was initially supported by a report that rats do not approach discrete cues paired with i.v. cocaine delivery (Kearns and Weiss, 2004). If it is true that "drugs and natural reinforcers differ fundamentally in this regard" a number of theories of addiction would require serious revision.…”

Behavioral characteristics and neurobiological substrates shared by Pavlovian sign-tracking and drug abuse

“…For example, Carroll and her associates have reported that pairings of the insertion of a lever CS with intravenous administration of drug reward US induced the automatic "shaping" of lever-pressing for drug self-administration in rats. Procedures of this sort have been employed to induce reliable leverpressing for the self-administration of the cocaine US (Carroll and Lac, 1993, 1998Specker et al, 1994;Gahtan et al, 1996;Lynch and Carroll, 1999;Lynch et al, 2001;Campbell and Carroll, 2001;Campbell et al, 2002;Carroll et al, 2002;Roth et al, 2002; see also Panlilio et al, 1996;Weiss et al, 2003 c.f., Di Ciano andKearns and Weiss, 2004), orthe self-administration of the amphetamine US (Carroll and Lac, 1997) or the self-administration of the heroin US (Lynch and Carroll, 1999;Carroll et al, 2002;Roth et al, 2002). In all of these studies, rats developed increasingly frequent lever-pressing as a function of experience with repeated pairings of lever CS with rewarding drug US.…”

Antagonism at NMDA receptors, but not β-adrenergic receptors, disrupts the reconsolidation of pavlovian conditioned approach and instrumental transfer for ethanol-associated conditioned stimuli

“…Attempts to study conditioned approach and PIT with drugs of abuse have had limited success, perhaps due to the absence of a consummatory sequence of behaviour to a specific location that brings an animal into direct contact with the goal, which may be necessary for these conditioned responses to be established (Flagel et al 2010;Kearns and Weiss 2004). Consequently, investigations of the reconsolidation of drug-associated memories have focused primarily upon the conditioned reinforcing properties of stimuli associated with drugs of abuse (Lee et al 2005(Lee et al , 2006aMilton et al 2008a, b).…”