Spontaneously hypertensive, Wistar Kyoto and Sprague-Dawley rats differ in their use of place and response strategies in the water radial arm maze

This study further characterises the use of mnemonic systems in the spontaneously hypertensive rat (SHR), which is frequently used as a rodent model of attention deficit hyperactivity disorder. The objective of this study was to assess the preference of male SHR, Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats for a place or response strategy when trained on an ambiguous T-maze task, and also to examine whether all strains acquired information about both strategies during ambiguous training, regardless of their preferred strategy. In the first experiment, SHR and WKY showed a preference for a response strategy on the ambiguous T-maze task; in contrast, SD displayed a preference for a place strategy. In the second experiment, all strains demonstrated that they learned information about both the response and place strategies during ambiguous training. However, on a conditioned place preference test SHR did not display as strong a preference for the place arm as WKY and SD. This finding supports previous research in a conditioned cue preference test, in which SHR did not display a preference for the cue associated with the platform. These observations that the strains differ with respect to behavioural strategy in a learning task suggest that they differ in the underlying neural circuitry that serves goal-directed behaviour, and are consistent with SHR having deficits associated with the nucleus accumbens.     

Group process: A developmental view

Group process is a phenomenon which is still only partly understood. This paper investigates different factors which might contribute to group process and possible group developmental sequences. Theoretical ideas are illustrated in the context of a two-day therapeutic group experience.     

Observing responses and informative stimuli

Pigeons were trained on a trial procedure. A trial began with the illumination of a pecking key by a white light. After a fixed interval, a key peck could turn the key to one of two equi-probable colors and produce a delayed trial outcome—an equi-probable occurrence of either reinforcement or nonreinforcement. After a trial, the key turned dark and the trial ended. The response could be made into an observing response by correlating the key colors with the outcomes. Response rates in the fixed interval then increased to a level greater than when the colors and outcomes were uncorrelated. In another phase, the response produced only the colors. The trial outcomes occurred some seconds after the fixed interval without a response being required. Correlating the colors with the outcomes again increased response rates. In a second experiment, a further condition was added in which reinforcement was the outcome on every trial. Response rates were lower than when there were equi-probable reinforcement and nonreinforcement outcomes with correlated colors, and about the same as when there were equi-probable outcomes with uncorrelated colors. The results suggest that stimuli providing information about the probability of reinforcement are themselves reinforcing.     

Psychometric, diurnal, and electrophysiological correlates of activation.

Several studies were performed using Thayer's Activation-Deactivation Adjective Check List (AD-ACL). Factor analysis of college students' scores identified a single activation factor representing a continuum ranging from sleep through wakefulness. Next, changes over the diurnal cycle in activation factor scores were demonstrated. One-week test-retest reliability was also investigated. Finally, activation scores were related to pulse rate, respiration rate, and skin resistance level under passive and active conditions. Correlations between factor scores and electrophysiological measures were higher than were intercorrelations of electrophysiological measures, indicating that scores on this revised activation factor represent a valid measure of phenomenological bodily activation level.     

Evaluation of a home-based language training programme with severely mentally handicapped children

A home-based Language Training Programme was carried out with pre-school and school-age severely mentally handicapped children, over a 16–18-month period. Compared to control groups, the experimental groups did not show significantly greater progress on normreferenced measures of language development, although all groups showed significant improvement over time. The implications of these findings are discussed in the light of a number of methodological problems with the study.     

Intrinsic religious motivation and attitudes toward death among the elderly

Forty-five males and females ages 65 and older completed the Intrinsic Religious Motivation Scale, a measure of faith development (based on Fowler, 1981), and two multidimensional measures of death anxiety (the Collett-Lester Fear of Death Scale-Revised and the Multidimensional Fear of Death Scale). Individuals with intrin-sic religious motivation reported significantly lower levels of various types of death anxiety than did individuals with extrinsic religious motivation. No significant rela-tionships were found between stage of faith and attitudes toward death and dying.