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.

Dopamine D(2)-like receptor binding in the brain of male Japanese quail (Coturnix japonica).

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.

Conditioned place preference in 12-day-old Japanese quail.

Four experiments assessed the ability of 12-day-old Japanese quail to learn a conditioned place preference (CPP). In Experiment 1, immature quail learned to prefer a place paired with normal food over a place paired with tainted food. Experiment 2 indicated that this kind of learning can be achieved with as few as 2 days of training. It was discovered in Experiment 3 that place preferences can be established with exposure to only one hedonic event. Quail learned to prefer a chamber paired with either normal food or tainted food over a chamber that did not contain a hedonic stimulus. Experiment 4 successfully replicated the 2-day normal-food-induced place preference in the previous experiment, while also showing that mere context exposure is not sufficient to produce CPP.

The topography of sexually conditioned behaviour: effects of a trace interval.

In a trace conditioning procedure, subjects were presented with a 30-sec conditioned stimulus (CS) followed by a 30-sec trace interval. Delayed conditioning consisted of a 60-sec CS presentation followed by an unconditioned stimulus (US). Although conditioning developed with both procedures, the topography of the conditioned response differed. Sexual conditioned approach was evident in all of the subjects during the presentation of the CS. Trace-conditioned subjects moved away from the area where the CS had been presented during the trace interval but remained closer to the CS location than did an unpaired control. This reduction in the spatial specificity of the conditioned response was interpreted from a behaviour systems perspective. The trace interval presumably increased the perceived separation between the CS and the US and therefore elicited conditioned behaviour less specifically directed towards the CS.

Imitative learning in male Japanese quail (Coturnix japonica) using the two-action method.

The study of imitative learning in animals has suffered from the presence of a number of confounding motivational and attentional factors (e.g., social facilitation and stimulus enhancement). The two-action method avoids these problems by exposing observers to demonstrators performing a response (e.g., operating a treadle) using 1 of 2 distinctive topographies (e.g., by pecking or by stepping). Japanese quail (Coturnix japonica) observers exposed to conspecific demonstrators showed a high correlation between the topography of the response they observed and the response they performed. These data provide strong evidence for the existence of true imitative learning in an active, precocious bird under conditions that control for alternative accounts.

Stimulus control of copulatory behavior in sexually naive male Japanese quail (Coturnix japonica): effects of test context and stimulus movement.

Sexually experienced male quail (Coturnix japonica) are more likely to engage in copulatory behavior than sexually naive ones. These experiments suggest that sexual experience in a particular place may facilitate later copulatory responding because of increased familiarity with the contextual cues of the environment. Male quail in Experiment 1 did not copulate reliably with taxidermic models of females in a novel context, even though some of the subjects were allowed to copulate with female quail in their home cages. In contrast, sexually naive males in Experiments 2 and 3 copulated vigorously with taxidermic models of females in a familiar context. In Experiment 4, sexually naive males tested in an unfamiliar context were more likely to copulate with a moving than with a static model. The stimulus control of copulatory behavior in sexually naive male quail was similar to that in sexually experienced ones but only in familiar contexts.

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.

Stimulus control of copulatory behavior in male Japanese quail.

The copulatory behavior of sexually experienced male Japanese quail was tested using taxidermic models with varying proportions of natural and artificial features. Completely artificial models exerted little control over copulatory behavior, and whole natural body models reliably elicited copulatory behavior. In single model presentation tests, a model containing a natural head and neck with an artificial body was as effective in eliciting copulatory behavior as a whole body model, but a model containing a natural body with an artificial head and neck was largely ineffective. In choice tests, however, males clearly preferred a whole model over a natural head and neck model, and a natural body model over a completely artificial model. These data indicate male Japanese quail do attend to features of body plumage. Furthermore, test procedures can influence conclusions about effective controlling stimuli.