Neurocognitive Aging and the Compensation Hypothesis

ABSTRACT— The most unexpected and intriguing result from functional brain imaging studies of cognitive aging is evidence for age-related overactivation: greater activation in older adults than in younger adults, even when performance is age-equivalent. Here we examine the hypothesis that age-related overactivation is compensatory and discuss the compensation-related utilization of neural circuits hypothesis (CRUNCH). We review evidence that favors a compensatory account, discuss questions about strategy differences, and consider the functions that may be served by overactive brain areas. Future research directed at neurocognitively informed training interventions may augment the potential for plasticity that persists into the later years of the human lifespan.     

琥珀酰明胶容量治疗对脑死亡后血清TNF—α、IL－1β、IL－6水平的影响

为了观察脑死亡后不同液体容量治疗对血清肿瘤坏死因子－α（TNF—α）、白细胞介素－1β（IL-1β）和白细胞介素－6（IL－6）等炎症介质水平改变的影响,选用巴马小型猪15只,随机分为3组各5只,即对照组（C组）、4％改良琥珀酰明胶组（MFG组）及乳酸林格氏液组（RL组）。C组不建立脑死亡模型,给与乳酸林格氏液30ml·kg^-1·d^-1～40ml·kg^-1·d^-1。MGF组和RL组为脑死亡组,采用颅内加压法建立脑死亡模型,MFG组给与4％改良琥珀酰明胶溶液30ml·kg^-1·d^-1,RL组给与乳酸林格氏液30-40ml·kg^-1·d^-1。分别于麻醉后及首次判定脑死亡后3、16、12、18和24h留取血样,检测血清中TNF-α、IL-1β、IL--6水平。结果发现MGF组较RL组血压和心率平稳;RL组TNF--α、IL-1β和IL-6水平自脑死亡后3h点开始逐渐升高;MFG组TNF--α、IL--1β和IL-6水平脑死亡后3h点开始亦升高,但升高幅度均较RL组低;三组间自脑死亡后3h点开始,组间比较差异有统计学意义。提示脑死亡后血清炎症介质TNF—α、IL-1β和IL--6释放增加,琥珀酰明胶可抑制脑死亡后TNF--α、IL--6、IL-1β等炎症介质的释放,减轻炎症反应,改善机体状况。     

句法加工的脑机制

语言理解中,句法加工至关重要,它把各个意义单元以不同的方式整合起来,从而形成整体的意义表征。句法加工的脑机制是心理语言学比较关注的问题,目前由于ERP技术和功能成像技术的进步,使对这一机制的探讨成为可能。该文对有关句法加工的脑机制的研究进行了回顾与总结,并针对目前该领域存在的问题与争论进行了讨论     

Hemispheric visual atentional imbalance in patients with traumatic brain injury

We find a spatially asymmetric allocation of attention in patients with traumatic brain injury (TBI) despite the lack of obvious asymmetry in neurological indicators. Identification performance was measured for simple spatial patterns presented briefly to a locus 5 degrees into the left or right hemifield, after precuing attention to the same (ipsilateral) or opposite (cross-hemifield) side. Though the cue was non-predictive of target location overall, performance was significantly slower for cross than for ipsilateral trials in both patients and controls. We tested 21 TBI patients without overt focal brain damage and nine control subjects. Only patients demonstrated significantly worse performance for left side presentation in the ipsilateral condition. Furthermore, in the cross-hemifield condition, the left-right difference seen in TBI patients was significantly larger-reflecting a failure in producing a leftward attention shift. Again no significant difference was found in controls. These hemifield effects suggest an asymmetry in the ability of TBI patients in shifting attention to the left hemifield, whether from central fixation or from a cue in the contra-lateral hemifield. The results support basic hypotheses regarding visual attention: Attentional control may be asymmetric and attention may be a distributed, rather than localized cortical function.     

Media Violence and Social Neuroscience: New Questions and New Opportunities

ABSTRACT— Decades of research have demonstrated that exposure to violence on television can cause increases in aggression. The recent emergence of violent video games has raised new questions regarding the effects of violent media. The General Aggression Model (GAM) predicts that exposure to violent media increases aggressive behavior through one of three primary pathways (arousal, cognitions, and affect). Past psychophysiological research has supported GAM but has been limited to examining arousal-related variables. Recent advances in social neuroscience have opened the door to investigations of exposure to violent media on cognitive and affective components and their neurocognitive underpinnings. Neuroscience tools have the potential to provide answers to the new questions posed by recent advances in media technology.     

Etiologic Subtypes of Attention-Deficit/Hyperactivity Disorder: Brain Imaging, Molecular Genetic and Environmental Factors and the Dopamine Hypothesis

Multiple theories of Attention-Deficit/Hyper- activity Disorder (ADHD) have been proposed, but one that has stood the test of time is the dopamine deficit theory. We review the narrow literature from recent brain imaging and molecular genetic studies that has improved our understanding of the role of dopamine in manifestation of symptoms of ADHD, performance deficits on neuropsychological tasks, and response to stimulant medication that constitutes the most common treatment of this disorder. First, we consider evidence of the presence of dopamine deficits based on the recent literature that (1) confirms abnormalities in dopamine-modulated frontal-striatal circuits, reflected by size (smaller-than-average components) and function (hypoactivation); (2) clarifies the agonist effects of stimulant medication on dopaminergic mechanisms at the synaptic and circuit level of analysis; and (3) challenges the most-widely accepted ADHD-related neural abnormality in the dopamine system (higher-than-normal dopamine transporter [DAT] density). Second, we discuss possible genetic etiologies of dopamine deficits based on recent molecular genetic literature, including (1) multiple replications that confirm the association of ADHD with candidate genes related to the dopamine receptor D4 (DRD4) and the DAT; (2) replication of differences in performance of neuropsychological tasks as a function of the DRD4 genotype; and (3) multiple genome-wide linkage scans that demonstrate the limitations of this method when applied to complex disorders but implicate additional genes that may contribute to the genetic basis of ADHD. Third, we review possible environmental etiologies of dopamine deficits based on recent studies of (1) toxic substances that may affect the dopamine system in early development and contribute substantially to the etiology of ADHD; (2) fetal adaptations in dopamine systems in response to stress that may alter early development with lasting effects, as proposed by the developmental origins of health and disease hypothesis; and (3) gene-environment interactions that may moderate selective damage or adaptation of dopamine neurons. Based on these reviews, we identify critical issues about etiologic subtypes of ADHD that may involve dopamine, discuss methods that could be used to address these issues, and review old and new theories that may direct research in this area in the future.     

Parametrically Dissociating Speech and Nonspeech Perception in the Brain Using fMRI

Candidate brain regions constituting a neural network for preattentive phonetic perception were identified with fMRI and multivariate multiple regression of imaging data. Stimuli contrasted along speech/nonspeech, acoustic, or phonetic complexity (three levels each) and natural/synthetic dimensions. Seven distributed brain regions' activity correlated with speech and speech complexity dimensions, including five left-sided foci [posterior superior temporal gyrus (STG), angular gyrus, ventral occipitotemporal cortex, inferior/posterior supramarginal gyrus, and middle frontal gyrus (MFG)] and two right-sided foci (posterior STG and anterior insula). Only the left MFG discriminated natural and synthetic speech. The data also supported a parallel rather than serial model of auditory speech and nonspeech perception.     

Imagination and Reality: On the Relations Between Myth, Consciousness, and the Quantum Sea

There often appears to be a striking correspondence between mythic stories and aspects of reality. We will examine the processes of creative imagination within a neurobiological frame and suggest a theory that may explain the functions of myth in relation to the hidden aspects of reality. Myth is peppered with archetypal entities and interactions that operate to reveal hidden processes in reality that are relative to the human condition. The imagery in myths in a sense "sustains the true." That is, mythopoetic imagery keeps the interpretive process in experience closer to the actual nature of reality than the rational faculties operating alone are able to do. Indeed, whereas rationalizing can easily lead us awry, genuine myth rarely does. Explanations of events offered by cultures around the world are frequently couched in terms of mythic themes and events. An important function of myth is to provide a "field of tropes" that in-forms the lived experience of people. This paper focuses especially on those aspects of myth that represent facets of the quantum universe and give us clues as to the relationship between consciousness, symbolism, and reality.     

Gender Differences in Cognitive and Emotional Adjustment to Traumatic Brain Injury

This study examined gender differences in cognitive and emotional status after traumatic brain injury (TBI) among 262 men and 140 women with TBI referred for neuropsychological evaluations. In this cross-sectional study, cognition was measured in terms of both absolute level of functioning (i.e., raw/standard scores) and estimated decline from premorbid levels expressed as z-deficit scores in the following domains: intelligence [Wechsler Adult Intelligence Scale—Revised (WAIS-R)], memory and attention [Wechsler Memory Scale—Revised (WMS-R)], processing speed (Trails A), and cognitive flexibility (Trails B). Emotional functioning was measured in terms of depression (Beck Depression Inventory) and general emotional distress (Brief Symptom Inventory). Kruskal–Wallis nonparametric one-way ANOVAs indicated that women and men differed significantly on 2 of 8 raw/standard cognitive scores [men demonstrated lower WMS-R General Memory (p < .05) and Trails B scores (p < .0001) and 4 of 8 relative decline scores [women demonstrated more estimated change in VIQ (Verbal IQ) [p < .0001], FSIQ (Full Scale IQ) [p < .01], and Attention (p < .01)]; men demonstrated greater estimated z-decline scores on Trails B (p < .01)]. Women reported significantly higher levels of depression (p < .01), but men endorsed significantly greater general psychological distress (p < .05). Research and assessment recommendations are suggested.     

人类的判断为什么不精确：进化论和脑科学的解释

人类的判断并非十分精确,而且人类还无法清醒认识到自己判断并不准。进化心理学理论认为看似不精确的判断最小化了人类付出的生存代价,从而使个体具有更大的收益,在竞争资源中具有适应优势;而脑科学领域运用fMRI、TMS等技术发现了前额叶的某些区域与判断的精确性有关。未来的研究有待结合进化发展心理学的角度、进化适应的现实解释性角度和认知神经科学发现临床应用的角度展开。