Eliciting Self-Explanations Improves Understanding

Learning involves the integration of new information into existing knowledge. Generating explanations to oneself (self-explaining) facilitates that integration process. Previously, self-explanation has been shown to improve the acquisition of problem-solving skills when studying worked-out examples. This study extends that finding, showing that self-explanation can also be facilitative when it is explicitly promoted, in the context of learning declarative knowledge from an expository text. Without any extensive training, 14 eighth-grade students were merely asked to self-explain after reading each line of a passage on the human circulatory system. Ten students in the control group read the same text twice, but were not prompted to self-explain. All of the students were tested for their circulatory system knowledge before and after reading the text. The prompted group had a greater gain from the pretest to the posttest. Moreover, prompted students who generated a large number of self-explanations (the high explainers) learned with greater understanding than low explainers. Understanding was assessed by answering very complex questions and inducing the function of a component when it was only implicitly stated. Understanding was further captured by a mental model analysis of the self-explanation protocols. High explainers all achieved the correct mental model of the circulatory system, whereas many of the unprompted students as well as the low explainers did not. Three processing characteristics of self-explaining are considered as reasons for the gains in deeper understanding.     

Movement abnormalities predict conversion to Axis I psychosis among prodromal adolescents

Evidence suggests that movement abnormalities are a precursor of psychosis. The link between movement abnormalities and psychotic disorders is presumed to reflect common neural mechanisms that influence both motor functions and vulnerability to psychosis. The authors coded movement abnormalities from videotapes of 40 adolescents at risk for psychosis (designated prodromal on the Structured Interview for Prodromal Symptoms; T. J. Miller et al., 2002). Following initial assessment, participants were evaluated for diagnostic status at 4 times annually. Ten participants converted to an Axis I psychosis (e.g., schizophrenia) over the 4-year period. Comparisons of converted and nonconverted participants at baseline indicated that the groups did not differ on demographic characteristics or levels of prodromal symptomatology, but those who converted exhibited significantly more movement abnormalities. Movement abnormalities and prodromal symptoms were strongly associated and logistic regression analyses indicated that abnormalities in the face and upper body regions were most predictive of conversion. Findings suggest that individuals with elevated movement abnormalities may represent a subgroup of prodromal adolescents who are at the highest risk for conversion. The implications for neural mechanisms and for identifying candidates for preventive intervention are discussed.     

Task dynamics and resource dynamics in the assembly of a coordinated rhythmic activity.

Task dynamics corresponding to rhythmic movements emerge from interactions among dynamical resources composed of the musculature, the link segments, and the nervous and circulatory systems. This article investigated whether perturbations of interlimb coordination might be effect over circulatory and nervous elements. Stiffness of wrist-pendulums oscillated at a common tempo and at 180 degrees relative phase was perturbed through the use of tonic activity about an ankle. Left and right stiffnesses, the common period, and the phase relation all changed. Stiffnesses increased with ankle torque in proportion to the wrist's inertial load. Despite different changes in stiffness at the two wrists, isochrony was preserved. The stability was shown to be consistent with the proportionality of changes in stiffness to the inertial loads. The phase departed from antiphase in proportion to the asymmetry of inertial loads. The size of departures decreased with increasing ankle torque. An account was developed in terms of muscular, circulatory, and nervous functions.     

Reproductive dysfunction in women with epilepsy: antiepileptic drug effects on sex-steroid hormones

Women with epilepsy are at risk for reproductive health dysfunction. Sex-steroid hormone abnormalities have been reported in women with epilepsy, but it has been difficult to determine whether these abnormalities are due to epilepsy-related hypothalamic-pituitary axis dysfunction, or to pharmacokinetic actions of antiepileptic drugs (AEDs). Sex-steroid hormones were evaluated in 84 reproductive-aged women with epilepsy receiving an AED in monotherapy, and in 20 nonepileptic controls. Estrone, free testosterone, and androstenedione were significantly lower in subjects receiving enzyme-inducing AEDs than in nonepileptic controls. Free testosterone was significantly elevated in subjects receiving valproate compared to nonepileptic controls. Subjects with epilepsy receiving gabapentin or lamotrigine were no different from the nonepileptic controls in any of the endocrine variables. Subjects with epilepsy who are receiving AEDs that alter cytochrome P450 enzymes are at risk for significant abnormalities in sex-steroid hormones. In contrast, subjects receiving AEDs that do not alter cytochrome P450 enzymes show no differences in sex-steroid hormones compared with nonepileptic controls. With new AEDs available that do not alter cytochrome P450 enzymes, physician selection of therapy should consider not only seizure control, but also potential effects on reproductive physiology.     

Learning and memory of factual content from narrative and expository text

Background. Research on the presentation of information in narrative versus expository text genres is inconclusive with respect to the question of which is more beneficial for student learning. Aims. We examine the effect of presenting factual content in either narrative or expository genres on student learning. We also consider relevant prior knowledge and working memory capacity (WMC) as potential mediating variables. Sample. Ninety university undergraduate students. Methods. Subjects studied circulatory system content embedded in either narrative or expository texts. Prior circulatory system knowledge, knowledge improvement (learning) and free recall were assessed. Results. Learning and recall did not differ as a function of text genre overall, but did interact with prior knowledge. Learning from the narrative and one expository text was optimal at intermediate levels of prior knowledge, with higher knowledge readers benefiting more from the expository text compared with the narrative text. Prior knowledge was positively related to recall for the expository texts, but unrelated for the narrative text. Subjects' WMC did not predict learning or recall. Conclusions. Results suggest that narrative and expository processing differ with respect to integration of text content with prior knowledge.     

Brain abnormalities observed in childhood-onset schizophrenia: a review of the structural magnetic resonance imaging literature

Childhood-onset schizophrenia (COS) is a rare, severe form of schizophrenia in which there are structural brain abnormalities that may be related to the psychotic symptomatology and neurocognitive deficits found in these patients. While there are numerous structural imaging studies of the adult-onset variant of schizophrenia (with many conflicting findings), relatively few brain imaging studies of COS have been conducted. This paper summarizes the extant literature of magnetic resonance imaging (MRI) studies of structural brain abnormalities in COS, and compares findings to similar studies of adult-onset patients. Volumetric MRI studies of COS patients have consistently shown evidence for increased ventricular volume, reduced cerebral gray matter, and increased caudate volume, consistent with findings from adult-onset studies. Other volumetric brain abnormalities are observed in COS patients, such as reduced total brain volume, but not consistently across all studies. Voxel-based morphometric analyses have revealed abnormalities in the shape and spatial location of structures in COS such as the corpus callosum, caudate, and thalamus that could not be observed in the more traditional volumetric assessments. Similar findings also are observed in adult-onset patients. Progressive degenerative changes, such as ventricular enlargement, appear to occur in COS only until young adulthood where there is an apparent asymptote with no further degenerative changes. This is consistent with the lack of progressive changes noted in most longitudinal studies of adult-onset schizophrenia.     

Addressing Consent Issues in Donation After Circulatory Determination of Death

Given the widening gap between the number of individuals on transplant waiting lists and the availability of donated organs, as well as the recent plateau in donations based on neurological criteria (i.e., brain death), there has been a growing interest in expanding donation after circulatory determination of death. While the prevalence of this form of organ donation continues to increase, many thorny ethical issues remain, often creating moral distress in both clinicians and families. In this article, we address one of these issues, namely, the challenges surrounding patient and surrogate informed consent for donation after circulatory determination of death. First we discuss several general concerns regarding consent related to this form of organ donation, and then we address additional issues that are unique to three different patient categories: adult patients with medical decision-making capacity or potential capacity, adult patients who lack capacity, and pediatric patients.     

Donation after circulatory death: burying the dead donor rule

Despite continuing controversies regarding the vital status of both brain-dead donors and individuals who undergo donation after circulatory death (DCD), respecting the dead donor rule (DDR) remains the standard moral framework for organ procurement. The DDR increases organ supply without jeopardizing trust in transplantation systems, reassuring society that donors will not experience harm during organ procurement. While the assumption that individuals cannot be harmed once they are dead is reasonable in the case of brain-dead protocols, we argue that the DDR is not an acceptable strategy to protect donors from harm in DCD protocols. We propose a threefold alternative to justify organ procurement practices: (1) ensuring that donors are sufficiently protected from harm; (2) ensuring that they are respected through informed consent; and (3) ensuring that society is fully informed of the inherently debatable nature of any criterion to declare death.     

The relationship between language-processing and visual-processing deficits in developmental dyslexia.

Some research on developmental dyslexia focuses on linguistic abnormalities such as poor reading of nonwords or poor reading of exception words. Other research focuses on visual abnormalities such as poor performance on psychophysical tasks believed to assess the functioning of the magnocellular and parvocellular layers of the lateral geniculate nucleus (LGN). Little is known about what the relationships are between these two types of abnormalities. We measured nonword reading, exception word reading, and performance with Ternus apparent movement displays (the perception of which is believed to depend upon the magnocellular and parvocellular pathways) in dyslexic children and children without reading difficulties. Our results indicate that performance on the Ternus task is related to nonword reading ability but not to exception word reading ability. We offer two alternative interpretations of these findings. According to the first of these, nonword reading requires a serial left-to-right allocation of covert attention across the letter string being read and the neural systems involved in this attentional process also play a part in responses to the Ternus display. According to the second, poor nonword reading and abnormal Ternus performance are not directly related: perinatal/neurodevelopmental insult has affected the LGN (influencing Ternus performance) and the adjacent medial geniculate nucleus (MGN; affecting phonological ability) and the MGN abnormalities may be more functionally related to poor nonword reading.     

When are you dead enough to be a donor? Can any feasible protocol for the determination of death on circulatory criteria respect the dead donor rule?

The basic question concerning the compatibility of donation after circulatory death (DCD) protocols with the dead donor rule is whether such protocols can guarantee that the loss of relevant biological functions is truly irreversible. Which functions are the relevant ones? I argue that the answer to this question can be derived neither from a proper understanding of the meaning of the term “death” nor from a proper understanding of the nature of death as a biological phenomenon. The concept of death can be made fully determinate only by stipulation. I propose to focus on the irreversible loss of the capacity for consciousness and the capacity for spontaneous breathing. Having accepted that proposal, the meaning of “irreversibility” need not be twisted in order to claim that DCD protocols can guarantee that the loss of these functions is irreversible. And this guarantee does not mean that reversing that loss is either conceptually impossible or known to be impossible with absolute certainty.

     

Maximal care considerations when treating patients with end-stage heart failure: ethical and procedural quandaries in management of the very sick

Deciding who should receive maximal technological treatment options and who should not represents an ethical, moral, psychological and medico-legal challenge for health care providers. Especially in patients with chronic heart failure, the ethical and medico-legal issues associated with providing maximal possible care or withholding the same are coming to the forefront. Procedures, such as cardiac transplantation, have strict criteria for adequate candidacy. These criteria for subsequent listing are based on clinical outcome data but also reflect the reality of organ shortage. Lack of compliance and non-adherence to lifestyle changes represent relative contraindications to heart transplant candidacy. Mechanical circulatory support therapy using ventricular assist devices is becoming a more prominent therapeutic option for patients with end-stage heart failure who are not candidates for transplantation, which also requires strict criteria to enable beneficial outcome for the patient. Physicians need to critically reflect that in many cases, the patient’s best interest might not always mean pursuing maximal technological options available. This article reflects on the multitude of critical issues that health care providers have to face while caring for patients with end-stage heart failure.     

PTSD,comorbid depression,and the cortisol waking response in victims of intimate partner violence: preliminary evidence

Posttraumatic Stress Disorder (PTSD) and Major Depressive Disorder (MDD) are two highly comorbid and debilitating disorders experienced by more than half of intimate partner violence victims (IPV). Hypothalamic–pituitary–adrenal (HPA) abnormalities are common in both disorders, though the direction of abnormalities often differs. The present study examined the relationship between comorbid PTSD and MDD, and the (salivary) cortisol waking response in 104 recently abused IPV victims. Waking cortisol levels, area under the waking curve with respect to ground (AUCg), and AUC with respect to increase (AUCi) were examined to determine the relation of HPA dynamics to comorbidity for basal versus more dynamic measures. Prior to accounting for comorbidity, women with PTSD or MDD showed significantly greater AUCi than women without the respective disorder. Accounting for comorbidity, PTSD only did not differ from other groups, while MDD only and PTSD + MDD showed greater AUCi than women with neither disorder. Results were nonsignificant for waking cortisol levels or AUCg. Results suggest that MDD drives elevated waking cortisol response, but not basal cortisol activity in recently abused IPV victims. Results demonstrate the importance of examining comorbid diagnoses and HPA activity from a dynamic perspective. Therapeutic implications are discussed.     

Effects of object complexity and type on the gaze behavior of children with pervasive developmental disorder

The looking behavior of children with pervasive developmental disorder (PDD) and age- and IQ-matched normal control children was studied using infrared oculography. Stimuli varying in complexity and topic were presented to test whether children with PDD have specific abnormalities in looking behavior to complex stimuli and/or to faces. All children showed more and longer fixations on the complex objects than on the simple objects, especially the complex nonsense figure, but group differences were not found. The results show no evidence for specific abnormalities in looking behavior to either faces or to complex stimuli in high functioning children with PDD.     

Evidence for specificity of ERP abnormalities during response inhibition in ADHD children: A comparison with reading disorder children without ADHD

Executive function and working memory deficits are not only present in ADHD, but also in reading disorder (RD). Here, high-density ERPs were recorded during the Stop Signal Task in 53 children and adolescents: An ADHD-combined type group, a group with RD, and a healthy control group. The ADHD-C group displayed unique abnormalities of the frontal N200. Both healthy controls and RD groups showed a success-related right frontal N200 modulation, which was absent in the ADHD group. Second, for Success Inhibition trials, the ADHD-C had smaller right frontal N200 waves relative to healthy controls, while the RD group did not. In contrast, NoGo-P3 abnormalities were present both in the ADHD-C and RD groups. Impaired early response inhibition mechanisms, indexed by the frontal N200, appear to be limited to ADHD-C. In contrast, deficits in later cognitive control and error monitoring mechanisms, indexed by the NoGo-P3, appear to be present in both conditions.     

Structural brain abnormalities in psychopaths-a review

The biological basis of psychopathy has not yet been fully elucidated. Few studies deal with structural neuroimaging in psychopaths. The aim of this article is to review these studies in order to contribute to our understanding of the biological basis of psychopathy. Data in the literature report a reduction in prefrontal gray matter volume, gray matter loss in the right superior temporal gyrus, amygdala volume loss, a decrease in posterior hippocampal volume, an exaggerated structural hippocampal asymmetry, and an increase in callosal white matter volume in psychopathic individuals. These findings suggest that psychopathy is associated with brain abnormalities in a prefrontal-temporo-limbic circuit-i.e. regions that are involved, among others, in emotional and learning processes. Additionally, data indicate that psychopathic individuals cannot be seen as a homogeneous group. The associations between structural changes and psychopathic characteristics do not enable causal conclusions to be drawn, but point rather to the important role of biological brain abnormalities in psychopathy. To gain a comprehensive understanding of this, psychopathy must be viewed as a multifactorial process involving neurobiological, genetic, epidemiological and sociobiographical factors.     

The Temporal and Dynamic Nature of Self-Regulatory Processes During Independent and Externally Assisted Hypermedia Learning

This study examined the temporal and dynamic nature of students’ self-regulatory processes while learning about the circulatory system with hypermedia. A total of 74 undergraduate students were randomly assigned to 1 of 2 conditions: independent learning or externally assisted learning. Participants in the independent learning condition used a hypermedia environment to learn about the circulatory system on their own, while participants in the externally assisted condition used the same hypermedia environment, but were given prompts and feedback from a human tutor during the session to facilitate their self-regulatory behavior. Previously published pretest–posttest shifts toward more mature understanding of the circulatory system indicate that the externally assisted condition leads to greater learning. The present article uses think-aloud data during learning to explore process issues in light of models of self-regulated learning and conditions of engagement that may affect those processes. Results indicate that access to a human tutor influences the deployment of regulatory processes, intervals of use, and temporal dependencies. For example, there is significantly more planning during the final time interval of the learning session in the externally assisted condition; students in both conditions deploy more learning strategies in the first and second time intervals, compared to the last two time intervals. Additionally, in the externally assisted condition participants were more likely to shift from planning to monitoring and less likely to shift from learning strategies to planning. We discuss theoretical, conceptual, and methodological issues pertaining to these results, as well as implications for future research and the design of adaptive hypermedia systems.     

The influence of expertise on X-ray image processing

Observers with four different levels of radiological experience performed a recognition memory task on slides of faces and chest X-ray films. Half of the X-ray films revealed clinically significant abnormalities and half did not. Recognition memory for faces was uniformly high across all levels of radiological experience. Memory for abnormal X-ray films increased with radiological experience and, for the most experienced radiologists, was equivalent to memory for faces. Surprisingly, recognition memory for normal films actually decreased with radiological experience from above chance to a chance level. These results indicate that radiological expertise is associated with selective processing of clinically relevant abnormalities in X-ray images. Expert radiologists appear to process X-ray images the way that we all process faces, by quickly detecting and devoting processing resources to features that distinguish one stimulus from another. However, the selective processing of X-ray films appears to be restricted to clinically relevant abnormalities. As they develop the ability to detect these abnormalities, radiologists appear to lose the ability to detect variations in normal features.     

网络成瘾者的大脑异于常人吗?

研究网络成瘾者的大脑是否异于常人的问题有助于对网络成瘾进行定性、诊断和治疗。近年来认知神经科学研究发现, 与正常人相比, 网络成瘾者的大脑主要存在四个方面的异常：①额叶和扣带回多部位存在结构性萎缩和功能退化, 导致其对上网行为的冲动控制出现障碍。②海马功能障碍, 导致其认知功能特别是工作记忆能力下降。③奖赏中枢功能代偿性增强, 可能与其多巴胺系统的功能异常有关。④内囊后肢的神经纤维结构较密、活性较高, 可能与其长时间兴奋性操作键盘、鼠标或游戏手柄有关。目前的研究结果至少说明：网络成瘾者的大脑存在一些功能性的、与物质成瘾者类似的异常, 但这些异常是否由网络成瘾导致, 以及这些异常是结构性的, 还是持久性的, 则还需要进一步的研究来证实。     

Cognitive and functional deterioration in patients with severe COPD

The objective of this study was to examine the association among the duration of COPD, degree of hypoxemia, and neurological abnormalities including cognitive functioning. Fifty-four patients with severe COPD and 24 age- and sex-matched controls, were included in the study. All patients and controls were administered pulmonary function tests, standardized Mini-mental State Examination (MMSE), Blessed Dementia Scale (BDS), Physical Self-maintenance Scale (PSMS), Modified Activities of Daily Living scale (MADL), Instrumental Activities of Daily Living scale (IADL), Cornell Scale for Depression in Dementia (CSDD), Global Deterioration Scale (GDS) and Clinical Dementia Rating (CDR). In addition, detailed physical and neurological examinations were performed. Sixty-four percent of patients with COPD showed abnormalities in MMSE, predominantly in recent memory, construction, attention, language, and orientation domains. Functional abnormalities were correlated with cognitive abnormalities. Although COPD patients did not show significant depression compared to controls, 77.7%. of the patients showed subjective and objective cognitive disturbance and 72.2% of the patients were classified as questionable or mild dementia. In conclusion, patients with COPD show significant cognitive and functional impairments that cannot be explained just by coincidence or by depression.