Showing papers by "Trevor W. Robbins published in 1976"

Relationship between reward-enhancing and stereotypical effects of psychomotor stimulant drugs.

Abstract: BLEULER has described stereotyped behaviour as “one of the most striking external manifestations of schizophrenia”1. Schizophrenic stereotyped behaviour has been found in the spheres of movement, action, posture, speech, writing, thought aid desire1. Abuse of the psychomotor stimulant drugs, such as the amphetamines, methylphenidate, cocaine and pipradrol, can cause a psychosis which is clinically indistinguishable from paranoid schizophrenia2, and which contains stereotyped components2,3. In animals, acute doses of the stimulants can induce stereotyped behaviour which is apparently under minimal situational control, and which can disrupt normal activity4. In contrast, low doses of the stimulants can apparently improve learning and performance in a variety of situations, in both animals5 and man6. This paper demonstrates a relationship between these two apparently diverse actions.

Locomotor activity and exploration: The use of traditional manipulators to dissociate these two behaviors in the rat

Abstract: An apparatus designed by Berlyne was used to dissociate locomotor activity and inspective exploratory responses with the aid of traditional manipulators. In this apparatus, novel and complex stimulation increased exploration but did not affect locomotor activity (LA). d-amphetamine (1.5 mg/kg) increased LA but decreased exploration. These findings provide a double dissociation of the behavioral components. In addition. low intrasubject correlations for the two behaviors were demonstrated. Results are discussed with reference to the need for simultaneous separate measures to obtain valid indices of exploratory behavior and LA. When placed in a novel environment, rats move around. At first sight, this behavior seems no more than simple ambulation. However, if the novelty or the degree of complexity of stimulation in the environment is manipulated, the amount and nature of the motor behavior varies (Berlyne, 1950; Schneider & Gross, 1965; Woods & Davidson, 1964). Such results indicate that general activity in any par­ ticular situation is compounded of what one might describe as "pure locomotor" behavior (Lore, 1968) together with an exploratory element, which may be manipulated by traditional elicitors, such as novelty and complexity of environmental stimulation. It has often been suggested that in studies of spontaneous locomotor behavior, these two contrib­ uting components have neither been recognized nor independently measured (Berlyne, 1960; Bindra & Spinner, 1958; Lester, 1968). This has been felt to be particularly true of experiments using apparatus such as the Y -maze, where a measure of locomotion is often assumed to be exploratory in nature with no prior rationale for such an assumption (e.g., Montgomery, 1955; Steinberg, Rushton, & Tinson, 1961). Simultaneous observation of both behavioral components has been attempted in the past by Corman and Shafer (1968), Foshee, Vierck, Meier, and Federspiel (1965), and Kumar (1969). However, in none of these studies was there an attempt to manipulate each of the two behavioral components separately, by means of independent variables within the same experimental design, nor was a low intra­ subject correlation between the two behavioral components demonstrated. Robbins and Iversen (1973), using a modified

The effects of d-amphetamine on temporal discrimination in the rat

Abstract: The effects of d-amphetamine on temporal discrimination in the rat were studied. Rats were trained on a two-manipulandum task involving the discrimination between two tones differing only in duration. d-Amphetamine (0.1–1.6 mg/kg) disrupted performance on this task, although not in an obvious dose-related manner. Lever biases were enhanced by the drug, but inconsistently among rats. Enhanced lever bias did not necessarily correlate with deterioration of performance. The drug lengthened both response latency and the performance of terminal components of the operant chain. However the characteristic pattern of response latencies produced by the two tones was not altered significantly by the drug. The results are discussed in terms of whether the drug disrupts discrimination performance by a direct effect on processes of temporal discrimination or indirectly, by its other effects on behavior.