Major psychosis and chromosome 22: genetics meets epigenetics

Elucidation of genetic factors in schizophrenia and bipolar disorder remains a challenging task to psychiatric researchers. As a rule, data from genetic linkage and association studies are quite controversial. In this article, we further explore the possibility that in addition to DNA sequences variation, a putative epigenetic dysregulation of brain genes plays an important role in the etiopathogenesis of major psychosis. We provide an epigenetic interpretation of unclear genetic findings specifically pertaining to chromosome 22 in schizophrenia and bipolar disorder. It is suggested that epigenetic strategies, when applied in conjunction with traditional genetic ones, may significantly expedite the uncovering of the molecular causes of major psychosis.     

Genetic approaches to understanding brain development: holoprosencephaly as a model

Holoprosencephaly (HPE) is the most common major developmental defect of the forebrain in humans. Clinical expression is variable, ranging from a small brain with a single cerebral ventricle and cyclopia to clinically unaffected carriers in familial HPE. Significant etiologic heterogeneity exists in HPE and includes both genetic and environmental causes. Defects in the cell signaling pathway involving the Sonic Hedgehog (SHH) gene, as well as defects in the cholesterol biosynthesis have been shown to cause HPE in humans. More recently, HPE genes from additional signaling pathways have been identified. These discoveries and current genetic approaches serve as a paradigm for studying normal and abnormal brain morphogenesis. MRDD Research Reviews 6:15-21, 2000.     

Stochastic approaches to understanding dissociations in inflectional morphology

Computer modelling research has undermined the view that double dissociations in behaviour are sufficient to infer separability in the cognitive mechanisms underlying those behaviours. However, all these models employ multi-modal representational schemes, where functional specialisation of processing emerges from the training process. Targeted lesioning of different regions of functional specialisation leads to varied but predictable deficits in model performance. We argue that multi-modal representational schemes are not a necessary condition for the observation of double dissociations in an information processing system that shares resources across multiple tasks. Using a uni-modal representational system, we demonstrate that double dissociations may also result from stochastic processes. Lesioning experiments on a single-route, uni-modal connectionist model of regular and irregular noun and verb morphology confirm and extend earlier work demonstrating that selective impairment across tasks can result from damage to a distributed information processing system. A systematic investigation of the degree to which performance deteriorates across different inflectional classes reveals that simple and double dissociations can occur in this single-route, uni-modal model. An important prediction of the model is that double dissociations between regular and irregular inflection, resulting from stochastic processes should be extremely rare. However, they are particularly likely to occur when the researcher uses test batteries consisting of a small number of items. Given that cognitive neuropsychologists rarely provide details about the distribution of performance in a disordered population, it is concluded that a stochastic interpretation of double dissociations may have wider applicability than is normally supposed.     

New approaches to understanding unconscious processes: Implicit and explicit memory systems

Abstract

Freud viewed the unconscious as being roughly equivalent to dynamically repressed wishes, needs, and motivations. Findings from developmental psychology, cognitive psychology, psychoanalysis, and neuroscience over the past 40 years have dramatically changed our views of unconscious processes and the human mind. It is now clear that Freud's dynamic unconscious is only a minor segment of information that is processed at subsymbolic, implicit, and automatic levels. Only a fraction of this information is further processed at explicit conscious levels. Moreover, the vast majority of the information that remains nonconscious is adaptive and has major consequences for development. We examine some clinical implications of these views.     

Goal theory vs. control theory: Contrasting approaches to understanding work motivation

Control theory has been propounded as an original and useful paradigm for integrating a number of theories of human (especially work) motivation. This paper challenges that claim. First, it is shown that the original, mechanical control theory model is not applicable to human beings. Second, it is shown that the two approaches used by control theorists to remedy its limitations did not succeed. One approach involved incorporating propositions drawn from other theories with the result that there was nothing distinctive left that was unique to control theory. The other approach involved broadening the scope of control theory by adding deduced propositions; however, these propositions were inconsistent with what was already known about the phenomena in question based on empirical research. The control theory approach to theory building is contrasted with that of goal setting theory (Locke & Latham, 1990). Goal-setting theory is a grounded theory (Glaser & Strauss, 1967) which evolved from research findings over a 25-year period. Goal theory developed in five directions simultaneously: validation of the core premises; demonstrations of generality; identification of moderators; conceptual refinement and elaboration; and integration with other theories. It is hypothesized that the grounded theory approach is a more fruitful one than the approaches used by control theory.The author wishes to thank Judy Olian for her helpful comments on this paper and Dong-OK Chah for making the figures.     

Complementary variable- and person-centred approaches to the dimensionality of work engagement: a longitudinal investigation

This study illustrates complementary variable- and person-centred approaches to the investigation of the underlying dimensionality of the work engagement construct. A sample of 730 participants completed a questionnaire twice across a four-month period. The results showed that employees’ ratings of their work engagement simultaneously reflected a global overarching work engagement construct, which co-existed with three specific dimensions (vigour, dedication, and absorption). Relying on factor scores from this initial measurement model, the present study examined latent profiles of employees defined based on their global (work engagement) and specific (vigour, dedication, and absorption) levels of work engagement. The results revealed five distinct work engagement profiles, which proved to be fully identical, and highly stable, across the two time points. These profiles characterized disengaged-vigorous, normative, totally disengaged, vigorously absorbed, and engaged yet distanced employees. These profiles were also showed to be meaningfully related to employees’ levels of stress, intentions to leave the organization, health, and job satisfaction.     

Different approaches to understanding patients in general practice in Denmark: a qualitative study

General practitioners (GPs) treat more than 90% of common mental disorders. Their approaches to psychological interventions have been little studied and their process of understanding patients remains unexplored. This qualitative interview and observation study aimed to explore Danish GPs’ approaches to emotional problems and mental disorders in ‘talking therapy’ and in routine consultations. Different typical approaches were identified and could be described using the concept of mentalisation. Some participants used a basic reflective approach but no well-described method. Others were satisfied with the biomedical professional identity and did not engage in patients' emotional problems. The individual participant's approach in talking therapy was mirrored in routine consultations. Training a mentalising or reflective stance might promote more uniform therapeutic approaches to patients' emotional problems.     

Mental retardation genes in drosophila: New approaches to understanding and treating developmental brain disorders

Drosophila melanogaster is emerging as a valuable genetic model system for the study of mental retardation (MR). MR genes are remarkably similar between humans and fruit flies. Cognitive behavioral assays can detect reductions in learning and memory in flies with mutations in MR genes. Neuroanatomical methods, including some at single-neuron resolution, are helping to reveal the cellular bases of faulty brain development caused by MR gene mutations. Drosophila fragile X mental retardation 1 (dfmr1) is the fly counterpart of the human gene whose malfunction causes fragile X syndrome. Research on the fly gene is leading the field in molecular mechanisms of the gene product's biological function and in pharmacological rescue of brain and behavioral phenotypes. Future work holds the promise of using genetic pathway analysis and primary neuronal culture methods in Drosophila as tools for drug discovery for a wide range of MR and related disorders.     

Nice to know you: Positive emotions, self-other overlap, and complex understanding in the formation of a new relationship

Based on Fredrickson's ((1998). What good are positive emotions? Review of General Psychology, 2, 300-319.; (2001). The role of positive emotions in positive psychology: The broaden-and-build theory of positive emotions. American Psychologist, 56, 218-226) broaden-and-build theory and Aron and Aron's ((1986). Love as expansion of the self: Understanding attraction and satisfaction. New York: Hemisphere) self-expansion theory, it was hypothesized that positive emotions broaden people's feelings of self-other overlap in the beginning of a new relationship. In a prospective study of first-year college students, we found that, after 1 week in college, positive emotions predicted increased self-other overlap with new roommates, which in turn predicted a more complex understanding of the roommate. In addition, participants who experienced a high ratio of positive to negative emotions throughout the first month of college reported a greater increase in self-other overlap and complex understanding than participants with a low positivity ratio. Implications for the role of positive emotions in the formation of new relationships are discussed.     

Frameworks for understanding emotions and their development: functionalist and dynamic systems approaches

In recent years, both functionalist and dynamic systems approaches have assumed increasing prominence in the study of emotion and its development, but the similarities and differences between these perspectives remain largely unexplored and open to more systematic examination. In this article, the authors argue that both approaches share a systems view of emotion and regard emotion in relational, process terms. However, each approach adopts a distinct level of analysis and distinct types of explanation for emotion and its development. Whereas the functionalist approach appeals to formal and final causes to explain patterning in emotion at the level of organism-environment relations, the dynamic systems approach appeals to efficient and material causes to explain emotion at the specific content level of behavior in context. Whether these approaches complement or conflict with one another depends on the extent to which the dynamic systems approach admits abstraction into its explanatory framework. A. Fogel's social process theory and M. D. Lewis' approach to emotion self-organization are discussed in this regard.     

Affective organizational commitment and citizenship behavior: Linear and non-linear moderating effects of organizational tenure

Utilizing a meta-analytical approach for testing moderating effects, the current study investigated organizational tenure as a moderator in the relation between affective organizational commitment and organizational citizenship behavior (OCB). We observed that, across 40 studies (N = 11,416 respondents), the effect size for the relation between affective organizational commitment and non-self measures of OCB was .23. However, we also found that organizational tenure moderated the relation in a non-linear way. Before 10 years of tenure, the strength of the commitment–OCB relation increased as organizational tenure increased; after that point, the strength of the commitment–OCB relation decreased as organizational tenure increased. In short, the moderating effect of tenure follows a curvilinear pattern.     

Stress risk factors and stress-related pathology: neuroplasticity, epigenetics and endophenotypes

This paper highlights a symposium on stress risk factors and stress susceptibility, presented at the Neurobiology of Stress workshop in Boulder, CO, in June 2010. This symposium addressed factors linking stress plasticity and reactivity to stress pathology in animal models and in humans. Dr. J. Radley discussed studies demonstrating prefrontal cortical neuroplasticity and prefrontal control of hypothalamo-pituitary-adrenocortical axis function in rats, highlighting the emerging evidence of the critical role that this region plays in normal and pathological stress integration. Dr. M. Kabbaj summarized his studies of possible epigenetic mechanisms underlying behavioral differences in rat populations bred for differential stress reactivity. Dr. L. Jacobson described studies using a mouse model to explore the diverse actions of antidepressants in brain, suggesting mechanisms whereby antidepressants may be differentially effective in treating specific depression endophenotypes. Dr. R. Yehuda discussed the role of glucocorticoids in post-traumatic stress disorder (PTSD), indicating that low cortisol level may be a trait that predisposes the individual to development of the disorder. Furthermore, she presented evidence indicating that traumatic events can have transgenerational impact on cortisol reactivity and development of PTSD symptoms. Together, the symposium highlighted emerging themes regarding the role of brain reorganization, individual differences, and epigenetics in determining stress plasticity and pathology.     

Intelligence: genetics, genes, and genomics

More is known about the genetics of intelligence than about any other trait, behavioral or biological, which is selectively reviewed in this article. Two of the most interesting genetic findings are that heritability of intelligence increases throughout the life span and that the same genes affect diverse cognitive abilities. The most exciting direction for genetic research on intelligence is to harness the power of the Human Genome Project to identify some of the specific genes responsible for the heritability of intelligence. The next research direction will be functional genomics--for example, understanding the brain pathways between genes and intelligence. Deoxyribonucleic acid (DNA) will integrate life sciences research on intelligence; bottom-up molecular biological research will meet top-down psychological research in the brain.     

A scoping review of non-linear analysis approaches measuring variability in gait due to lower body injury or dysfunction

ObjectivesThe aim of this review is to evaluate and summarize existing literature using non-linear analysis methodology to consider variability of human movement due to lower limb injury or dysfunction.DesignScoping review.MethodsAn electronic keyword search was performed on three databases to identify appropriate research. This research was then examined for details of measures and methodology, use of control groups and general study characteristics to identify related themes.ResultsFifteen papers were reviewed and synthesized. A range of conditions were studied, mainly affecting knee and ankle joints, and each using different non-linear methods and different equipment (motion capture, accelerometry, and muscle activation) to evaluate the mathematically chaotic nature of the movement and assess the variability in gait. Sample sizes and effect sizes are commonly small in these studies.ConclusionsNon-linear analysis is a potentially useful tool in both diagnosis and evaluation of injury, and this should inform future clinical processes when dealing with injury and movement variability. Despite numerous studies evaluating neurological conditions and ageing, focus on injury is limited, with notable gaps in terms of considering other joints and joint actions, so this should be a promising area of research to develop our understanding of injury and rehabilitation and how this affects gait variability.     

Language,belief and plurality: a contribution to understanding religious diversity

My purpose in this paper is to defend the legitimacy of different religious systems by showing that they arise naturally as a consequence of the fact that we are linguistic beings. I will show that we do not need to presume that such belief systems all have something in common, and that even if they did we would most probably be unaware of it. I shall argue, however, that this lack of a common core does not mean that understanding between different belief systems is impossible, and that, in fact, a dialogue between them is possible without one system being reduced to another. I will defend these ideas through the use of some principles expounded in Wittgenstein’s On Certainty, especially the world-picture concept.