MR imaging of fetal central nervous system abnormalities

Ultrasound is the screening modality of choice for fetal imaging. However, when additional information regarding fetal anatomy or pathology is needed, fast MR imaging is increasingly being used as a correlative imaging modality. Performances of high quality sonographic and MR examinations as well as interpretation by individuals familiar with prenatal diagnosis are important factors for optimal parental counseling. MR imaging frequently adds additional information regarding fetal central nervous system anomalies beyond that available with ultrasound. This information commonly changes patient counseling, and at times patient management.     

Women's knowledge of prenatal ultrasound and informed choice

This study evaluated women's understanding of prenatal ultrasound in terms of meeting the requirements for informed choice. A cross-sectional survey was conducted to evaluate (1) how information is provided, (2) women's perceived value of the information received and, (3) their understanding of ultrasound in relation to the principles of informed choice. Women (n = 113) completed a questionnaire prior to their 18-week ultrasound. Fifty-five percent stated they received no information from their care provider. Only 31.9% considered health care providers as a very helpful source of information. Yet, 69.0% stated their care provider gave them information that facilitated their understanding. Gaps were identified in women's understanding of ultrasound. Specifically, 46.0% did not view ultrasound as a screen for anomalies; some were uncertain about the safety (18.6%), diagnostic capabilities (26.5%), and limitations of testing (37.2%). These results suggest that women's understanding of ultrasound does not meet the requirements of informed choice.     

Schizophrenia risk and paternal age: a potential role for de novo mutations in schizophrenia vulnerability genes

How schizophrenia (SZ) is maintained at roughly 1% of the population despite diminished reproduction is one puzzle currently facing researchers. De novo mutations were first proposed over half a century ago as a source for new SZ genes. Current evidence linking advancing paternal age to SZ risk makes revisiting this hypothesis important. Advancing paternal age is the major source of new mutations in the human population. This article will examine potential mechanisms whereby parental age may impact new mutations, as well as review recent data supporting such a hypothesis.     

Environmental factors associated with a spectrum of neurodevelopmental deficits

A number of environmental agents have been shown to demonstrate neurotoxic effects either in human or laboratory animal studies. Critical windows of vulnerability to the effects of these agents occur both pre- and postnatally. The nervous system is relatively unique in that different parts are responsible for different functional domains, and these develop at different times (e.g., motor control, sensory, intelligence and attention). In addition, the many cell types in the brain have different windows of vulnerability with varying sensitivities to environmental agents. This review focuses on two environmental agents, lead and methylmercury, to illustrate the neurobehavioral and cognitive effects that can result from early life exposures. Special attention is paid to distinguishing between the effects detected following episodes of poisoning and those detected following lower dose exposures. Perinatal and childhood exposure to high doses of lead results in encephalopathy and convulsions. Lower-dose lead exposures have been associated with impairment in intellectual function and attention. At high levels of prenatal exposure, methylmercury produces mental retardation, cerebral palsy and visual and auditory deficits in children of exposed mothers. At lower levels of methylmercury exposure, the effects in children have been more subtle. Other environmental neurotoxicants that have been shown to produce developmental neurotoxicity include polychlorinated biphenyls (PCBs), dioxins, pesticides, ionizing radiation, environmental tobacco smoke, and maternal use of alcohol, tobacco, marijuana and cocaine. Exposure to environmental agents with neurotoxic effects can result in a spectrum of adverse outcomes from severe mental retardation and disability to more subtle changes in function depending on the timing and dose of the chemical agent.     

From power to action

Three experiments investigated the hypothesis that power increases an action orientation in the power holder, even in contexts where power is not directly experienced. In Experiment 1, participants who possessed structural power in a group task were more likely to take a card in a simulated game of blackjack than those who lacked power. In Experiment 2, participants primed with high power were more likely to act against an annoying stimulus (a fan) in the environment, suggesting that the experience of power leads to the performance of goal-directed behavior. In Experiment 3, priming high power led to action in a social dilemma regardless of whether that action had prosocial or antisocial consequences. The effects of priming power are discussed in relation to the broader literature on conceptual and mind-set priming.     

From covariation to causation: a test of the assumption of causal power

How humans infer causation from covariation has been the subject of a vigorous debate, most recently between the computational causal power account (P. W. Cheng, 1997) and associative learning theorists (e.g., K. Lober & D. R. Shanks, 2000). Whereas most researchers in the subject area agree that causal power as computed by the power PC theory offers a normative account of the inductive process. Lober and Shanks, among others, have questioned the empirical validity of the theory. This article offers a full report and additional analyses of the original study featured in Lober and Shanks's critique (M. J. Buehner & P. W. Cheng, 1997) and reports tests of Lober and Shanks's and other explanations of the pattern of causal judgments. Deviations from normativity, including the outcome-density bias, were found to be misperceptions of the input or other artifacts of the experimental procedures rather than inherent to the process of causal induction.     

Consequences of Child Exposure to War and Terrorism

Acts of war and terrorism are increasingly prevalent in contemporary society. Throughout history, weaponry has become more efficient, accurate, and powerful, resulting in more devastation and loss of human life. Children are often overlooked as victims of such violence. Around the world, children are exposed to violence in multiple forms, frequently developing traumatic stress reactions. Such reactions are best understood within the context of social-emotional and cognitive development, as children respond differently to the stress of violence depending on their developmental level. Furthermore, the violence of war and terrorism often results in a multitiered cascade of negative life events including loss of loved ones, displacement, lack of educational structure, and drastic changes in daily routine and community values. These numerous losses, challenges, and stresses affect children's brains, minds, and bodies in an orchestrated whole-organism response. This paper describes these effects, synthesizing the current state of research on childhood traumatic stress reactions from the fields of neuroscience, clinical psychology, and pediatric diagnostic epidemiology.     

Motor sequence learning and reading ability: is poor reading associated with sequencing deficits?

Although it is widely assumed that children with learning disabilities have "sequencing problems," these have not been well specified. A non-verbal serial reaction time (SRT) paradigm was used to evaluate motor sequence learning in 422 children between ages 7 and 11 in relation to reading, cognitive ability level, and attention problems. The children demonstrated the response profile typically associated with motor sequence learning, but the component of the profile indicative of implicit sequence learning was not reliably associated with any of the predictors. Cognitive ability predicted overall response time; cognitive ability, reading, and attention problems each predicted overall accuracy. Explicit learning was predicted by cognitive ability, but not by reading or attention problems. Thus, we found no evidence that poor reading is preferentially associated with a domain general deficit in sequential learning.     

Cognitive correlates of medial temporal lobe development across adolescence: a magnetic resonance imaging study

Adolescent development involves progressive changes in brain structure and cognitive function, but relatively few studies have documented the cognitive correlates of differences in structural brain volumes in this age group. We examined the relations among age, cognitive processing, and mesial temporal lobe volume in 37 children and adolescents. Participants completed a brief cognitive assessment battery and underwent volumetric structural magnetic resonance imaging. For the sample as a whole, amygdala volume correlated positively with age, and larger volumes of both the left and right amygdala were significantly associated with better performance on several cognitive tasks assessing academic skills and acquired knowledge in long-term memory. In contrast, hippocampal volumes did not correlate with adolescents' age and were less frequently correlated with cognitive performance. Amygdala volumes were most predictive of cognitive abilities in boys, whereas for girls, the volume of the hippocampus contributed more frequently to the prediction of cognitive abilities. These data suggest that measurable differences in mesial temporal volumes during adolescence are reliably associated with long-term cognitive abilities, particularly academic skills and the acquisition of intellectual knowledge, and that these relationships may differ as a function of the sex of the child.