Extinction of responding maintained by timeout from avoidance.
(1/1603)
The resistance to extinction of lever pressing maintained by timeout from avoidance was examined. Rats were trained under a concurrent schedule in which responses on one lever postponed shock on a free-operant avoidance (Sidman) schedule (response-shock interval = 30 s) and responses on another lever produced 2 min of signaled timeout from avoidance on a variable-ratio 15 schedule. Following extended training (106 to 363 2-hr sessions), two experiments were conducted. In Experiment 1 two different methods of extinction were compared. In one session, all shocks were omitted, and there was some weakening of avoidance but little change in timeout responding. In another session, responding on the timeout lever was ineffective, and under these conditions timeout responding showed rapid extinction. The within-session patterns produced by extinction manipulations were different than the effects of drugs such as morphine, which also reduces timeout responding. In Experiment 2 shock was omitted for many consecutive sessions. Response rates on the avoidance lever declined relatively rapidly, with noticeable reductions within 5 to 10 sessions. Extinction of the timeout lever response was much slower than extinction of avoidance in all 4 rats, and 2 rats continued responding at baseline levels for more than 20 extinction sessions. These results show that lever pressing maintained by negative reinforcement can be highly resistant to extinction. The persistence of responding on the timeout lever after avoidance extinction is not readily explained by current theories. (+info)
Reinstatement of alcohol-seeking behavior by drug-associated discriminative stimuli after prolonged extinction in the rat.
(2/1603)
Clinical observations suggest that stimuli associated with the availability or consumption of ethanol can evoke subjective feelings of craving and trigger episodes of relapse in abstinent alcoholics. To study the motivational significance of alcohol-related environmental cues experimentally, the effects of discriminative stimuli previously predictive of alcohol availability on the reinstatement of ethanol-seeking behavior were examined. Wistar rats were trained to lever-press for 10% (w/v) ethanol or water in the presence of distinct auditory cues. The rats were then subjected to an extinction phase where lever presses had no scheduled consequences. After extinction, the animals were exposed to the respective auditory cues without the availability of ethanol or water. Neither the ethanol (SA+) nor water-associated (SA-) auditory cue increased responding over extinction levels. In contrast, subsequent presentation of an olfactory cue associated with ethanol (SO+), but not a water-associated (SO-) cue significantly reinstated lever pressing behavior in the absence of the primary reinforcer. Moreover, responding elicited by the concurrent presentation of the SO+ and SA+ was selectively attenuated by the opiate antagonist naltrexone (0.25 mg/kg; s.c.). The results suggest that ethanol-associated cues can reinstate extinguished ethanol-seeking behavior in rats, but that the efficacy of these stimuli may be modality-specific. In addition, the present procedures may be useful for studying neurobiological mechanisms of alcohol-seeking behavior and relapse. (+info)
Side effects of extinction: prevalence of bursting and aggression during the treatment of self-injurious behavior.
(3/1603)
Findings from basic and applied research suggest that treatment with operant extinction may produce adverse side effects; two of these commonly noted are an increase in the frequency of the target response (extinction burst) and an increase in aggression (extinction-induced aggression). Although extinction is often used to treat problem behavior in clinical settings, few applied studies have examined the prevalence of these side effects or their possible attenuation with other operant procedures. An analysis of 41 data sets for individuals who received treatment for self-injurious behavior indicated that extinction bursts or increases in aggression occurred in nearly one half of the cases. The prevalence of bursting and aggression was substantially lower when extinction was implemented as part of a treatment package rather than as the sole intervention. (+info)
Clarifying an ambiguous functional analysis with matched and mismatched extinction procedures.
(4/1603)
Results of functional analysis were ambiguous in suggesting that self-injurious behavior (SIB) was maintained by escape, sensory reinforcement, or both. To help clarify these results, we compared escape extinction, sensory extinction, and the combined treatments. Sensory extinction proved to be a necessary and sufficient treatment, whereas escape extinction failed to decrease SIB. These analyses helped to clarify the function of SIB and to identify an effective and efficient treatment. (+info)
Dopamine fluctuations in the nucleus accumbens during maintenance, extinction, and reinstatement of intravenous D-amphetamine self-administration.
(5/1603)
Moment-to-moment fluctuations of nucleus accumbens dopamine (DA) were determined in rats self-administering or passively receiving "yoked" intravenous infusions of D-amphetamine. The initial lever presses of each session caused elevations in DA concentration, usually to an initial peak that was not maintained throughout the rest of the session. As the initial ("loading") injections were metabolized, DA levels dropped toward baseline but were sustained at elevated plateaus by subsequent lever pressing that was spaced throughout the remainder of the 3 hr sessions. During this period, DA levels fluctuated phasically, time-locked to the cycle of periodic lever pressing. Consistent with the known pharmacological actions and dynamics of amphetamine, peak DA elevations were seen approximately 10-15 min after each injection, and the mean DA level was at a low point in the phasic cycle at the time of each new lever press. During extinction periods when saline was substituted for amphetamine, DA levels dropped steadily toward baseline levels despite a dramatic increase in (now-unrewarded) lever pressing. Noncontingent injections during extinction reinstated lever-pressing behavior and increased nucleus accumbens DA concentrations. These data are consistent with the hypothesis that under the conditions of this experiment-during periods of amphetamine intoxication in well-trained animals-the timing of amphetamine self-administration comes primarily under the control of extracellular DA concentrations. The probability of lever pressing during the maintenance phase is highest when DA concentrations fall near a characteristic trigger point, a trigger point that is significantly elevated above baseline, and falls as DA concentrations fall below or increase above that trigger point. (+info)
Effects of reinforcement magnitude on spontaneous recovery.
(6/1603)
Extinction of operant behavior has been associated with a number of undesirable effects. One such effect is the temporary reappearance of behavior after responding appears to be completely extinguished, known as spontaneous recovery. In this report, the occurrence of spontaneous recovery and its attenuation with large amounts of reinforcement were examined during the treatment of disruption. (+info)
Caffeine, acting on adenosine A(1) receptors, prevents the extinction of cocaine-seeking behavior in mice.
(7/1603)
Drug-naive DBA/2 mice were trained to self-administer cocaine (40 microgram/kg/infusion) i.v. by nose poking. The number of nose-poke responses was higher in mice receiving response-contingent injections of cocaine (active group) than in yoked controls or in animals receiving response-contingent saline injections. Twenty-four hours after the training session (cocaine or saline self-administration), mice were injected i.p. with saline, cocaine, caffeine, 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX), 8-cyclopentyl theophylline (8-CPT), 5-amino-7-(2-phenylethyl)2-(2-furyl)-pyrazolo-[4,3-e]-1,2, 4-triazolo[1,5-c]pyrimidine (SCH 58261), or 9-chloro-2(2-furyl)[1,2, 4]triazolo[1,5-c]quinazolin-5-amine (CGS 15943) and placed again in exactly the same operant boxes as during the training session but without response-contingent i.v. infusions. Saline injection elicited similar responding in animals from the active group and from the yoked control group. A low dose of cocaine (5 mg/kg) or caffeine (3 mg/kg), but not higher doses, produced greater responding in the active group than in the yoked control group during a single extinction trial. The adenosine A(1)-receptor antagonists DPCPX and 8-CPT and the nonselective antagonist CGS 15943 partially reproduced the effect of a low dose of caffeine on the cocaine-associated behavior in a dose-dependent manner and did not alter the nose-poke activity of yoked control mice in the extinction experiment. In contrast, the adenosine A(2A) antagonist SCH 58261, in doses above 1 mg/kg, reduced nose-poke activity equally in active and yoked control animals. This confirms that a drug from a different pharmacological class (adenosine-receptor antagonist) can induce behavior changes similar to the effects of the original self-administered drug (indirect dopamine-receptor agonist). The data also suggest that the effects of caffeine on cocaine-seeking behavior might be related to interaction with adenosine A(1) receptors, but not A(2A) receptors. (+info)
Impaired eye-blink conditioning in waggler, a mutant mouse with cerebellar BDNF deficiency.
(8/1603)
In addition to their trophic functions, neurotrophins are also implicated in synaptic modulation and learning and memory. Although gene knockout techniques have been used widely in studying the roles of neurotrophins at molecular and cellular levels, behavioral studies using neurotrophin knockouts are limited by the early-onset lethality and various sensory deficits associated with the gene knockout mice. In the present study, we found that in a spontaneous mutant mouse, waggler, the expression of brain-derived neurotrophic factor (BDNF) was selectively absent in the cerebellar granule cells. The cytoarchitecture of the waggler cerebellum appeared to be normal at the light microscope level. The mutant mice exhibited no sensory deficits to auditory stimuli or heat-induced pain. However, they were massively impaired in classic eye-blink conditioning. These results suggest that BDNF may have a role in normal cerebellar neuronal function, which, in turn, is essential for classic eye-blink conditioning. (+info)