The neurological dynamics of the imagination

This article examines the imagination by way of various studies in cognitive science. It opens by examining the neural correlates of bodily metaphors. It assumes a basic knowledge of metaphor studies, or the primary finding that has emerged from this field: that large swathes of human conceptualization are structured by bodily relations. I examine the neural correlates of metaphor, concentrating on the relation between the sensory motor cortices and linguistic conceptualization. This discussion, however, leaves many questions unanswered. If it is the case that the sensory motor cortices are appropriated in language acquisition, how does this process occur at the neural level? What neural preconditions exist such that this appropriation is possible? It is with these questions in mind that I will turn my attention to studies of neural plasticity, degeneracy and the mirror neuron activation. Whereas some scholarship in philosophy and cognitive neuroscience has aimed to identify the neurological correlates of consciousness, examining plasticity, degeneracy and activation shifts the discussion away from a study of correlates toward an exploration of the neurological dynamics of thought. This shift seems appropriate if we are to examine the processes of the “imagination.”     

Associations between serum cortisol, cardiovascular function and neurological outcome following acute global hypoxia in the newborn piglet

Perinatal asphyxia is a significant contributor to neonatal brain injury. However, there is significant variability in neurological outcome in neonates after global hypoxia-ischemia. The aims of this study were to identify which physiological response/s during global hypoxia-ischemia influence the severity of brain injury and to assess their relative importance. Hypoxia/hypercapnia was induced in 20 anaesthetized piglets by reducing the inspired oxygen fraction to 10% and the ventilation rate from 30 to 10 breaths per minute for 45 min. Neurological outcome was assessed using functional markers including cerebral function amplitude (via electroencephalography) and cerebral impedance, and the structural marker microtubule associated protein-2 by immunohistochemistry at 6 h post hypoxia. Significant variability in neurological outcome was observed following the constant hypoxia/hypercapnia insult. There was a high degree of variability in cardiovascular function (mean arterial blood pressure and heart rate) and serum cortisol concentrations in response to hypoxia. More effective maintenance of cardiovascular function and higher serum cortisol concentrations were associated with a better outcome. These two variables were strongly associated with neurological outcome, and together explained 68% of the variation in the severity of neurological outcome. The variability in the cardiovascular and cortisol responses to hypoxia may be a more important determinant of neurological outcome then previously recognized.     

The clinical aspects of newborn screening: importance of newborn screening follow-up

The aim of newborn screening is to identify presymptomatic healthy infants that will develop significant metabolic or endocrine derangements if left undiagnosed and untreated. The goal of ultimately reducing or eliminating irreversible sequelae is reached by maximizing test sensitivity of the primary newborn screening that measures specific analytes by a number of methodologies. Differentiation of true from false negatives is accomplished by the test specificity. This review discusses disorders for which, in general, there are available therapies and that are detected by routine and expanded newborn screening. Recommendations are presented for evaluation by a primary care physician, with confirmation by a metabolic or endocrinology specialist. Disorders are organized in tabular format by class of pathway or analyte, with attention to typical clinical presentations, confirmatory biochemical and molecular tests, and therapies. There are numerous challenges in clinical follow-up, including diagnosis and appropriate understanding of the consequences of the disorders. The data required to meet these challenges can be acquired only by large scale longitudinal comprehensive studies of outcome in children identified by newborn screening. Only with such data can newborn screening fully serve families.     

The assessment of neurological systems with functional imaging

In recent years a number of multivariate approaches have been introduced to map neural systems in health and disease. In this review, we focus on spatial covariance methods applied to functional imaging data to identify patterns of regional activity associated with behavior. In the rest state, this form of network analysis can be used to detect abnormal topographies reflecting regional changes in distributed neural systems. In activation experiments, this approach can be used to quantify network-performance relationships in normal and disease cohorts. Functional changes in the relevant neural systems are likely to underlie the behavioral abnormalities observed in a variety of disease and treatment conditions.     

The diagnosis of neurological disorders in older adults

Are neurological disorders overdiagnosed in older adults? Previous reports suggest that age bias may lead to diagnostic inaccuracies for older adult clients. In the present study, the average test scores for community-dwelling 38-year-old and 74-year-old individuals were presented as the results for a 38-year-old client and a 74-year-old client, respectively. Neuropsychologists did not make diagnoses of neurological disorder or dementiafor either of the clients. The results from this study indicate that age bias is not as serious a problem among neuropsychologists as many psychologists once believed.     

Modeling the neurological control of human movements

Although computer models have been extensively used in recent years to understand the way physical systems operate and interact, the enormous power of mathematical modeling and computer simulations has been difficult to implement for the benefit of neuroscientists studying the human motor control system. Nevertheless, homeomorphic models are now being used to explain and predict the neural and biomechanical aspects of different human movements. This paper argues for the importance of regarding model simulations as a supplementary approach to traditional methods of experimental investigation by drawing examples from both the experimental and the modeling literature. The discussion focuses on studies of the triphasic control signal for fast, goal-directed movements and on aspects of sampled data control for slow, tracking movements. The aim of this viewpoint article is to promote a more widespread use of modeling and simulation in the field of motor control.