Scopolamine effects on memory retention in mice: a model of dementia?

Scopolamine-treated normal young human subjects exhibit memory dysfunctions analogous to those observed in demented patients. The dysfunctions are reversible by physostigmine but not by d-amphetamine which suggests that the memory impairment is specifically related to reduced cholinergic transmission caused by scopolamine. Scopolamine-induced amnesia has been proposed as a model for dementia where reduced cholinergic function is the suspected cause. We report seven experiments in young adult mice which examine scopolamine's effects on memory retention and whether its amnestic effects are specifically blocked by cholinergic agonists or cholinomimetics. Young adult mice were trained to avoid footshock in a T maze and their retention tested 1 week after training. Pretraining subcutaneous injection of scopolamine improved retention scores of "undertrained" mice at a dose of 0.01 mg/kg but impaired at a dose of 0.1 mg/kg. Post-training injection showed no effect at 0.01 mg/kg, enhanced retention scores at 0.1 mg/kg, and impaired at 1.0 mg/kg. The impairment by 1.0 mg/kg was blocked by injection 45 min post-training of each of two cholinergic drugs but was also counteracted by six drugs which act upon five other neural systems (catecholamine, serotonin, glycine, GABA, and hormonal). When scopolamine was injected 40 min pretraining, and each of eight drugs was injected immediately after training, the amnestic effect of scopolamine was only partially counteracted. This suggests that scopolamine impaired acquisition, in addition to some impairment of memory processing. This was confirmed by a direct study of acquisition rates of the avoidance response; 0.1 mg/kg of scopolamine impaired acquisition. The overall results indicate that pretraining administration of scopolamine impairs learning and to some degree memory processing. Counteracting scopolamine-induced amnesia, by either pretraining or post-training drug administration, is not specific to the cholinergic system.     

Self‐ratings of sense of direction and route reversal performance

One of the most pervasive beliefs about human way finding is that some people have a natural ability that distinguishes them from others. In this research, we asked children and adults to rate their own sense of direction, a promising index of orientation skills despite its simplicity and reliance on self‐assessment. Ratings were obtained before and after reversal of a newly learned outdoor route. Self‐ratings by children and adults before route reversal only weakly predicted two of a variety of measures of route and bearing knowledge. However, adults' ratings after the route reversal reflected performance on almost all of these same measures. In addition, route reversal performance was easily improved by instructing children and adults during route acquisition to look back in anticipation of the return. The pattern of results suggests that way finders' beliefs about their sense of direction are based on a recollection of the outcomes of the attentive and mnemonic strategies they use. Copyright © 2002 John Wiley & Sons, Ltd.     

Job crafting for lean engagement: The interplay of day and job-level characteristics

The quality of working life under the production system known as lean manufacturing (LM) is a heavily debated topic. Little is known about the engagement level of employees under this system. Our study is concerned with how employees in this context craft their jobs to enhance their own engagement, and we specifically consider how daily skill utilization triggers this process. Using a cross-level perspective, we further consider whether job-level characteristics relevant to the lean context, namely task interdependence and boundary control, restrict or facilitate the effects of daily skill utilization. A daily diary study was conducted over 4 working days with 64 employees in a large company utilizing LM. The results of multilevel structural equation modelling demonstrated that on a given day, skill utilization was associated with seeking resources, and this relationship was stronger when employees had high boundary control and low task interdependence in their general job roles. Results further demonstrated that employees experienced higher work engagement on days when they sought resources and challenges. Our findings illustrate the motivational potential of job crafting under LM and how crafting activities can be facilitated by the design of jobs and allocation of daily tasks.     

From Intentions to Behavior: Implementation Intention,Commitment, and Conscientiousness1

Implementation intentions are said to transfer control over goal‐directed behavior to situational cues, thereby automating initiation of the behavior ( Gollwitzer, 1999 ). Alternatively, implementation intentions may be effective because they create commitment to the intended behavior. In an empirical study, implementation intentions regarding a simple task (rating TV newscasts) varied in their specificity. In addition, explicit commitment to the task was manipulated, and chronic conscientiousness was assessed. Consistent with the commitment hypothesis, general and specific implementation intentions were equally effective in raising level of task performance, and they were no more effective than asking for an explicit commitment to carry out the task. Also, individuals high in conscientiousness were more likely than individuals low on this trait to enact their intentions.     

Reducing stereotypic behavior through discrimination training,differential reinforcement of other behavior,and self‐monitoring

The effect of a treatment package designed to reduce stereotypic body rocking was examined in a child diagnosed with autism. After baseline, the participant was taught to discriminate between inappropriate (e.g. sitting in a chair and rocking) and appropriate (e.g. sitting in a chair without rocking) behavior. During intervention, both a therapist and the participant himself monitored the occurrence of rocking behavior. A non‐resetting 5 min differential reinforcement of other behavior (DRO) schedule was also introduced. A multiple baseline across behaviors (sitting and standing) design was used to evaluate the effects of the intervention package. The results indicated that the intervention was effective in eliminating body rocking. In addition, the DRO schedule was successfully increased to 20 min for sitting and 17 min for standing and the treatment was successfully introduced at the child's school. Copyright © 2001 John Wiley & Sons, Ltd.     

The utility of the PAI and the MMPI-2 for discriminating PTSD, depression, and social phobia in trauma-exposed college students

This study investigated the Minnesota Multiphasic Personality Inventory-Revised (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) and the Personality Assessment Inventory (PAI; Morey, 1991) with regard to each instrument's utility for discriminating post-traumatic stress disorder (PTSD) from depression and social phobia in a sample of college students with mixed civilian trauma exposure. Participants were 90 trauma-exposed undergraduates (16 male, 74 female) classified into one of four groups: PTSD, depressive disorders, social phobia, and well-adjusted. For both the PAI and the MMPI-2, profile analysis revealed that the groups differed in the elevation and shape of their profiles. The PAI Traumatic Stress subscale demonstrated good discriminant validity.