Effects of combined muscarinic and nicotinic blockade on choice accuracy in the radial-arm maze

Acetylcholine (ACh) systems have been found to be crucial for the maintenance of accurate cognitive performance. A great variety of studies have shown that the muscarinic ACh receptor blocker scopolamine impairs choice accuracy in the radial-arm maze. Recently, it has been found that the nicotinic ACh receptor blocker mecamylamine also impairs radial-arm maze choice accuracy. In the present study, we investigated the effects of combined administration of these two ACh blockers. Scopolamine (0.15 mg/kg) and mecamylamine (10 mg/kg) each moderately impaired choice accuracy. Combined treatment with scopolamine and mecamylamine significantly decreased choice accuracy relative to either drug alone. This combination treatment lowered choice accuracy to chance levels. These data show that nicotinic and muscarinic blockade have at least additive effects in producing an anterograde memory deficit. Concurrent blockade of these two components of ACh systems may provide a better animal model of cognitive impairments due to the loss of cholinergic neurons, such as Alzheimer's disease.     

RegRand: Statistical software for the multiple-baseline design

RegRand (Version 1.0) is Macintosh-based software that enables a researcher to conduct a nonparametric statistical analysis of the data from Koehler and Levin’s (1998) recently described regulated randomization single-case multiple-baseline design. Regulated randomization design and analysis principles are reviewed in relation to an educational research application and a step-by-step illustration of them in relation to the RegRand program is presented.     

Information Processing at Successive Stages of Decision Making: Need for Cognition and Inclusion-Exclusion Effects

Levin and Jasper's (1995) phased narrowing technique for tracking changes in information usage across successive stages of the decision-making process was combined with Huneke's (1996) “pull-down menu” extension of Payne, Bettman, and Johnson's (1988) software package for generating measures of information processing. Because this technique provided considerable data for each individual subject at each stage, we were able to focus on individual differences in information processing across stages, most notably differences related to need for cognition (NC; Cacioppo & Petty, 1982). In a computerized information search and decision task, 60 college students were first asked to narrow their options for purchasing a notebook computer to form a consideration set and were then asked to make a final choice from this set. At the consideration set formation stage, half the subjects were instructed to adopt a mindset to include options while the other half were asked to exclude options. Especially in the inclusion condition where subjects showed greater narrowing of options, high NC subjects processed information in a more focused manner with greater depth and breadth than did low NC subjects, and the quality of their selections tended to be higher. There was no evidence of widespread shifts in strategy as individuals moved from set formation to final choice but, as a group, high NC subjects were more successful at adaptive decision making.     

Simultaneous factor analysis of several Gramian matrices

Given several Gramian matrices, a least-square fit to all the matrices by one factor matrix, with a predetermined number of factors, is shown to be the principal axes solution of the average of the matrices.     

Effects of the nicotinic receptor blocker mecamylamine on radial-arm maze performance in rats

Lesions of cholinergic neurons have been found by many investigators to impair choice accuracy in the radial arm maze. Because muscarinic receptor blockers, such as scopolamine, have also repeatedly been found to impair choice accuracy in the radial-arm maze, it has generally been thought that the critical effect of cholinergic lesions is the deafferentation of muscarinic receptors. The possible involvement of nicotinic receptors in the cholinergic bases of cognitive performance in the radial-arm maze has not been as well investigated. The present study examined the effects of the blockade of nicotinic receptors on performance of female Sprague-Dawley rats in the radial-arm maze. Acute administration of the the nicotinic receptor blocker, mecamylamine (10 mg/kg) was found to significantly impair radial-arm maze choice accuracy. This dose also caused a significant increase in response latency in the maze. The effect on choice behavior but not locomotor speed seemed to be due to the central effects of mecamylamine, because administration of the peripheral nicotine receptor blocker, hexamethonium (20 mg/kg), did not impair choice accuracy, even though it did increase response latency to a similar degree as the 10-mg/kg dose of mecamylamine. Lower doses of mecamylamine (2.5 and 5 mg/kg) did not impair choice accuracy. These results indicate that central nicotinic as well as muscarinic cholinergic receptors are involved with cognitive functioning.     

Roles for the Black pastor in preventive medicine

In recent years, a new role for Black pastors has emerged. As agents of health-related social and behavioral change, Black ministers have taken active roles in preventive medicine at the tertiary, secondary, and primary levels of prevention, succeeding despite resistance by some physicians. The literature detailing these new health-related pastoral roles is reviewed, with special reference to the place of the Black Church in health care and to the place of the Black pastor in the Black experience. It is concluded that Black ministers are ideal people to take part in planning, promoting, and delivering preventive health care in the Black community.The author wishes to acknowledge Dr. John W. Hatch of the University of North Carolina School of Public Health, who supervised the preparation of an annotated bibliography upon which this paper is based.     

Infantile omnipotence and grandiosity

A distinction is made between infantile omnipotence and grandiosity. The retention of the former is considered necessary for health and the latter is considered pathological. The former is described as feeling comfortable though it can also be perceived both subjectively and objectively as irrational. The latter is viewed as ultimately distressing, though it can be subjectively experienced as necessary. Grandiosity is seen as a defense against repressed omnipotence. The repression of omnipotence appears to be caused by parents who are threatened by its power. Ways of making the distinction between omnipotence and grandiosity are discussed. Means of treatment and clinical examples are given.