Cholinergic-dopaminergic interactions in cognitive performance

Both acetylcholinergic (ACh) and dopaminergic (DA) systems have been found to be crucial for the maintenance of accurate cognitive performance. In a series of studies examining those aspects of cognitive function revealed by the radial-arm maze, we have found that these two neurotransmitter systems interact in a complex fashion. Choice accuracy deficits in the radial-arm maze can be induced by blockade of either muscarinic- or nicotinic-ACh receptors. The choice accuracy deficit induced by blockade of muscarinic receptors with scopolamine can be reversed by the DA receptor blocker, haloperidol. The specific DA D1 blocker SCH 23390 also has this effect, whereas the specific D2 blocker raclopride does not, implying that it is D1 blockade that is critical for reversing the scopolamine effect. On the other hand, the choice accuracy deficit induced by nicotinic blockade with mecamylamine is potentiated by haloperidol. This effect is also seen with the D2 antagonist raclopride, but not with the D1 antagonist SCH 23390, implying that it is the D2 receptor which is important for the potentiation of the mecamylamine effect. The relevance of the D2 receptor for nicotinic actions on cognitive function is emphasized by the finding that the selective D2 agonist LY 171555 reverses the choice accuracy deficit caused by mecamylamine. Nicotinic and muscarinic blockade are synergistic in the deficit they produce. Antagonist doses subthreshold when given alone produce a pronounced impairment when given together. This latter deficit can be reversed by the D2 agonist LY 171555. These studies have outlined the complex nature of ACh-DA interactions with regard to cognitive function. Possible neural circuits for these interactions are discussed. The effectiveness of these selective DA treatments in reversing cognitive deficits due to ACh underactivation suggests a novel approach to treating cognitive dysfunction in syndromes such as Alzheimer's disease.     

Maurice Merleau-Ponty and Rudolf Laban -- An Interactive Appropriation of Parallels and Resonances

In this paper, we propose an examination of the shared connections between the French philosopher, Maurice Merleau-Ponty and the Austro-Hungarian movement theorist, Rudolf Laban.In many ways Merleau-Ponty's philosophy demonstrates a synthesis of the best in existen-tialism and phenomenology. In like manner, Rudolf Laban was a synthesizer of experiences and theories of movement.we propose to examine the parallels and resonances of their theory within the forum of a hypothetical, collegial conversation. This dialogue will be prefaced by an historical contextualization of their work and an explanation of the appropriate reading sensibility with which to enter our interpretation of their text. In this way, we hope to reveal (a) possible parallels and resonances between their theories concerning the body in perception and movement, and (b) possible connections between phenomenology and movement education.     

A Nonmonotonic Modal Formalization of the Logic of Acceptance and Rejection

The problems we deal with concern reasoning about incomplete knowledge. Knowledge is understood as ability of an ideal rational agent to make decisions about pieces of information. The formalisms we are particularly interested in are Moore's autoepistemic logic (AEL) and its variant, the logic of acceptance and rejection (AEL2). It is well-known that AEL may be seen as the nonmonotonic KD45 modal logic. The aim is to give an appropriate modal formalization for AEL2.     

Conscience and conscientious actions in the context of MCOs

Managed care organizations can produce conflicts of obligation and conflicts of interest that may lead to problems of conscience for health care professionals. This paper provides a basis for understanding the notions of conscience and conscientious objection and offers a framework for clinicians to stake out positions grounded in personal conscience as a way for them to respond to unacceptable pressures from managers to limit services.     

The Question of God in an Age of Science: Constructions of Reality and Ultimate Reality in Theology and Science

Both science and theology have lately faced a crisis of authority. Their shared realization of the extent to which knowledge is underdetermined by the data and socially constructed provides a kind of common ground for reconsideration of their respective methods of inquiry as well as of the status of the claims they have warrant to make. Both fields are now consciously and critically employing a models approach. This article proposes criteria for assessing models and applies the criteria to one model from each field. The model of understanding evolution as a struggle for existence is considered from the field of science, and the traditional model for understanding the God-world relation as that of a king's relation to his kingdom is considered from the field of theology. Each of these models is evaluated with respect to its credibility, religious viability, and moral adequacy. In each case an alternative analogy is proposed and argued for.     

Youth at Risk: Another Point of View

In this rejoinder to Tidwell and Corona Garrett (1994), the authors discuss three important aspects of the term at risk that help to clarify its meaning.     

Anxious attachment and psychological distress in cardiac rehabilitation patients

This study investigated the relevance of anxious attachment to the differentiation of psychologically distressed and non-psychologically distressed cardiac patients. Attachment is a biologically based behavioral system in which proximity to a special other is sought or maintained to achieve a sense of safety and security. Anxious attachment, as the name denotes, fails to achieve the function of attachment in the sense of individuals having little or no confidence in the availability of their attachment figures. Empirically, three scales (feared loss of the attachment figure, proximity seeking and separation protest) capture the features of anxious attachment as elaborated by Bowlby. These scales were administered to 178 cardiac rehabilitation patients drawn from the cardiac rehabilitation program of the Calgary General Hospital. The results indicate that feared loss and proximity seeking differentiated psychologically distressed from non-psychologically distressed patients. The implications of this finding for the understanding of psychologically distressed cardiac patients are discussed.     

Content validity: A neglected strategy for developing managerial selection tests?

There is a lack of quick, valid, and cost effective methods for selection of low-and mid-level managerial personnel. Using content-valid methods to develop managerial selection instruments may reap substantial benefits for applicants as well as for the organizations using such tools. To this end, based upon extensive job analysis, a content-valid managerial selection test was developed. Criterion-based validity collected on the new instrument suggested that an instrument developed using content-valid procedures can also show acceptable levels of criterion validity.     

Effects of surface texture on weight perception when lifting objects with a precision grip

In this paper, we show that, when lifting an object using a precision grip with the distal pads of the thumb and index finger at its sides, the perceived weight depends on the object’s surface texture. The smoother the surface texture, the greater the perceived weight. We suggest that a smoother object is judged to be heavier because the grip force, normal to the surface, required to prevent it from slipping is greater. The possibility of there being an influence of surface texture per se is excluded by a second experiment that employed a variant of the precision grip in which the thumb supports the weight of the object from underneath. With the grip oriented in this way, there is no need to match grip force to surface texture and, under these conditions, there is no effect of surface texture on weight perception. In the first two experiments, the test and comparison weights were lifted successively by the same hand. In a third experiment, the effect of surface texture was replicated for sequential lifts made with separate hands. Thus, the effect is not restricted to comparisons made with the same hand.     

Gender,psychological well-being and somatic cardiovascular risk factors

The purpose of this study is to determine associations between cardiovascular risk factors and subjective experience of psychological general well-being with special reference to gender-related differences. One hundred fifty white-collar workers in a car manufacturing plant in Sweden participated in a health care screening program. Subjective experience of psychological well-being was significantly correlated with cardiovascular risk factors among both men and women. There were, however, marked differences between the genders. For men, the following specific psychological variables were significantly correlated with cardiovascular risk factors: estimation of general health, anxiety, self-control and vitality. For women, more complex significant relationships between the two sets of variables were found. Moreover, the direction of the correlations differed between the genders. For example, men with cardiovascular risk factors, such as increased blood pressure, blood lipids and body mass index, reported significantly morepositive estimation of their general health. For women the relation was the opposite with a significantly positive correlation (p-0.004) between experience of good health and a low risk factor profile indicating the concordance between physiological and psychological parameters. Possible reasons for these sex differences are discussed.