Chana K. Akins

Imitation in Japanese quail: The role of reinforcement of demonstrator responding

Imitative learning has been difficult to demonstrate in animals, partly because techniques have not adequately ruled out alternative accounts based on motivational and perceptual mechanisms (Zentall, 1996). Recently, it has been proposed that differences in the effects of observation of two very different responsetopographies would rule out such artifactual, alternative accounts (Akins & Zentall, 1996). In the present research, we confirmed that strong evidence for imitation can be found in Japanese quail, and that such imitation requires the imitator’s observation ofreinforced responding by the demonstrator. Thus, under the present conditions, it appears that an observer will imitate a demonstrated responseonly if it also observes the appetitive consequences of that response.

Topography of sexually conditioned behavior in male Japanese quail (Coturnix japonica) depends on the CS-US interval

The interval between exposure to a conditioned stimulus (CS) to male quail and access to a female (the unconditioned stimulus [US]) was varied from 0.5 to 20 min using a Pavlovian delayed conditioning procedure. Increasing the CS-US interval altered the spatial distribution of sexual conditioned behavior. With a short CS-US interval (1 min), conditioning resulted in the Ss remaining close to the CS and increasing their locomotor behavior near the CS. With a long CS-US interval (20 min), the Ss approached the CS to some degree, but their locomotor behavior was increased in areas further removed from the CS. Results are interpreted within the context of a behavior systems approach to the study of learning and indicate that the typical finding of an inverse relation between conditioned responding and the CS-US interval may be an artifact of the use of a limited range of behavioral measures.

Ionotropic Glutamate Receptors in the Ventral Tegmental Area Regulate Cocaine-Seeking Behavior in Rats

Drug addiction is characterized by compulsive drug-seeking and drug-taking behavior and by a high rate of relapse even after long periods of abstinence. Although the mesocorticolimbic dopamine (DA) pathway is thought to play a critical role in drug craving and relapse, recent evidence also implicates glutamate, an amino acid known to activate DA neurons in the ventral tegmental area (VTA) via ionotropic receptors. To assess whether increased glutamate transmission in the VTA is involved in cocaine-primed drug-seeking behavior, we tested rats in a between-session reinstatement model. They were trained to press a lever for cocaine infusions (0.25 mg/infusion) accompanied by compound stimuli (light and tone) under a modified fixed-ratio 5 reinforcement schedule. Cocaine-primed reinstatement was conducted after lever pressing was extinguished in the absence of the conditioned stimuli. Blockade of ionotropic glutamate receptors in the VTA by local application of kynurenate (0.0, 1.0, 3.2, and 5.6 μg/side) dose-dependently decreased cocaine-primed reinstatement, whereas sucrose-primed reinstatement of sucrose-seeking behavior was unaffected. In addition, the minimum effective dose for decreasing cocaine-primed reinstatement was ineffective in the substantia nigra. Together, these data indicate that glutamatergic activation of the VTA is critical for cocaine-primed reinstatement. Because such activation can increase impulse flow in DA neurons and thus DA release in mesocorticolimbic targets, this glutamate–DA interaction in the VTA may underlie cocaine-primed relapse to cocaine-seeking behavior.

Increased responding to female stimuli as a result of sexual experience: Tests of mechanisms of learning

Sexual experience increases the response of males to stimuli provided by female conspecifics in a variety of species. The mechanisms of learning involved in this type of phenomenon were explored in two experiments with Japanese quail. The results indicated that instrumental conditioning with copulatory opportunity is not necessary for the acquisition of responding to female cues, and responding is not facilitated by learning about the location of the female. However, the response of males to female stimuli (as well as to arbitrary stimuli associated with access to a female) was enhanced by the presence of sexually conditioned contextual cues. Substantial levels of responding also occurred to female stimuli in a context where the subjects never encountered a female quail before. This latter outcome is consistent with the possibility that stimuli from a female become directly associated with sexual reinforcement during the course of sexual experience. Similar forms of learning may be involved in the effects of sexual experience on the response of mammalian species to female odours.

Imitative learning in Japanese quail (Coturnix japonica ) using the bidirectional control procedure

In the bidirectional control procedure, observers are exposed to a conspecific demonstrator responding to a manipulandum in one of two directions (e.g., left vs. right). This procedure controls for socially mediated effects (the mere presence of a conspecific) and stimulus enhancement (attention drawn to a manipulandum by its movement), and it has the added advantage of being symmetrical (the two different responses are similar in topography). Imitative learning is demonstrated when the observers make the response in the direction that they observed it being made. Recently, however, it has been suggested that when such evidence is found with a predominantly olfactory animal, such as the rat, it may result artifactually from odor cues left on one side of the manipulandum by the demonstrator. In the present experiment, we found that Japanese quail, for which odor cues are not likely to play a role, also showed significant correspondence between the direction in which the demonstrator and the observer push a screen to gain access to reward. Furthermore, control quail that observed the screen move, when the movement of the screen was not produced by the demonstrator, did not show similar correspondence between the direction of screen movement observed and that performed by the observer. Thus, with the appropriate control, the bidirectional procedure appears to be useful for studying imitation in avian species.

Cocaine induces conditioned place preference and increases locomotor activity in male Japanese quail

The conditioned place preference (CPP) procedure is a popular method used for testing the rewarding properties of human drugs of abuse. Most CPP studies utilize mammalian models. However, avian species have better visual systems than rodent species, and because the cues that become associated with human drug-taking behavior are often visual, Aves might serve as an alternative animal model for investigating drugs of abuse. In three experiments, we examined the locomotor stimulant and rewarding effects of cocaine in adult male Japanese quail. In Experiment 1, cocaine increased locomotor activity relative to saline. In addition, behavioral sensitization was evident across repeated injections. In Experiment 2, CPP was established after six pairings of cocaine. Finally, the dopamine D(2) receptor subtype antagonist eticlopride did not attenuate acquisition of cocaine CPP in Experiment 3. Rather, subjects receiving pretreatment of eticlopride demonstrated a place preference for the cocaine-paired context. In contrast, pretreatment of eticlopride reduced cocaine-induced locomotor activity. The findings suggest that drug-reward processes may be highly conserved across species and that birds may serve as a viable model for investigating drug-reward processes especially with regard to the ability of cocaine to become associated with visual cues.

Dose-dependent cocaine place conditioning and D1 dopamine antagonist effects in male Japanese quail

The dopamine D1 receptor subtype has been implicated in drug reward processes in mammals. Two experiments investigated whether dose-dependent differences in cocaine conditioned place preference (CPP) would be obtained in an avian species and whether these cocaine effects were mediated by the dopamine D1 antagonist R(+/-)-SCH23390. In Experiment 1, male birds were given intraperitoneal injections of 1, 3, 10, or 30 mg/kg of cocaine hydrochloride, paired with a chamber that contained distinct visual cues. On alternate days, they received saline paired with a chamber containing different visual cues. A CPP test was given after four pairings of cocaine with the distinct chamber. In Experiment 2, 0.0025, 0.025, or 0.25 mg/kg of SCH 23390 or saline was administered 15 min prior to cocaine (3 mg/kg) and placement into the least preferred chamber. CPP was observed at 1, 3, and 10 mg/kg doses of cocaine but not at 30 mg/kg or saline. All doses of SCH 23390 attenuated cocaine-induced CPP. The findings suggest that cocaine administration results in a dose-dependent CPP, and that similar with mammals, it may be mediated by D1 receptors in an avian species. Thus, the avian species may be a beneficial comparative model for drug studies, especially those involving visual cue mechanisms of drug reward.

The discriminative stimulus effects of cocaine in a pavlovian sexual approach paradigm in male Japanese quail.

Two groups of male Japanese quail (Coturnix japonica) were trained [corrected] to discriminate cocaine from saline in a conditioned approach procedure maintained by sexual reinforcement. For 1 group, cocaine (10 mg/kg ip) was administered prior to a conditioned stimulus (CS) that predicted copulation; saline followed by a CS predicted no copulation. A second group underwent the opposite training regimen. Results revealed apparent between-group differences in the rates of acquisition of the discrimination; however, during extinction trials, both groups responded more under the drug condition that predicted the female than to the condition that predicted no female. The results suggested that a drug discrimination may be maintained by sexual reinforcement. The findings are discussed with regard to interactions of cocaine and sexual reward, as well as to Pavlovian conditional stimulus control.

Chronic cocaine pretreatment facilitates Pavlovian sexual conditioning in male Japanese quail.

Repeated drug exposure that results in behavioral sensitization has been shown to enhance sex-seeking behaviors in rats as well as facilitate Pavlovian excitatory and inhibitory conditioning. In the present experiment, male Japanese quail were given repeated presentations of cocaine (10 mg/kg, i.p.) that resulted in increased locomotor activity relative to saline. After a 10-day withdrawal period, subjects received sexual conditioning trials that consisted of presentation of an object conditioned stimulus (CS) followed by sexual reinforcement. Results showed that birds that previously received chronic cocaine demonstrated more conditioned approach behavior to the CS object, a shorter latency to copulate with a female, and made more cloacal contacts (copulatory behavior) during sexual reinforcement than saline-treated birds. The findings suggest that chronic cocaine later facilitates Pavlovian conditioning in a sexual behavior paradigm. This may be the result of cocaine facilitating learning via the dopaminergic system. The findings are discussed in the context of the incentive sensitization theory and possible neuronal mechanisms.

Dopamine D2-like receptor binding in the brain of male Japanese quail (Coturnix japonica)

Abstract Japanese quail ( Coturnix japonica ) have been used extensively to study appetitive behaviors. However, little is known about the appetitive-relevant neurochemical systems in this species. The present investigation examined the distribution of D 2 -like dopamine receptors in the quail brain. [ 3 H]Spiperone was incubated in brain tissue homogenates and non-specific binding was defined using (−)-sulpiride. Scatchard analysis of whole brain without cerebellum and forebrain alone indicated approximate K d s of 0.08 and 0.04 nM, respectively. In addition, the preferential D 3 agonist (±)-2-dipropylamino-7-hydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide (7-OH-DPAT) did not displace [ 3 H]spiperone binding in quail forebrain. Finally, regional analysis showed that the highest densities of D 2 -like receptors were located in the forebrain. Overall, these results indicate that there is some conservation of dopaminergic mechanisms between aves and mammals. Thus, Japanese quail may be useful for examining the neuropharmacological mechanisms of dopaminergic stimulant drugs that work via D 2 -like receptor activation.