Consciousness wanted,attention found: Reasons for the advantage of the left visual field in identifying T2 among rapidly presented series

Everyday experience suggests that people are equally aware of events in both hemi-fields. However, when two streams of stimuli are rapidly presented left and right containing two targets, the second target is better identified in the left than in the right visual field.This might be considered evidence for a right-hemisphere advantage in generating conscious percepts. However, this putative asymmetry of conscious perception cannot be measured independently of participants’ access to their conscious percepts, and there is actually evidence from split-brain patients for the reverse, left-hemisphere advantage in having access to conscious percepts. Several other topics were studied in search of the responsible mechanism, among others: Mutual inhibition of hemispheres, cooperation of hemispheres in perceiving midline stimuli, and asymmetries in processing various perceptual inputs. Directing attention by salient cues turned out to be one of the few mechanisms capable of modifying the left visual-field advantage in this paradigm. Thus, this left visual-field advantage is best explained by the notion of a right-hemisphere advantage in directing attention to salient events. Dovetailing with the pathological asymmetries of attention after right-hemisphere lesions and with asymmetries of brain activation when healthy participants shift their attention, the present results extend that body of evidence by demonstrating unusually large and reliable behavioral asymmetries for attention-directing processes in healthy participants.     

Left orbital frontal activation in pathological anxiety

Twelve patients with anxiety disorder were studied with respect to regional cerebral blood flow (rCBF) using a 32-detector system with the 133 Xe inhalation technique. Measurements were taken during a rest condition and during anxiety induction. Anxiety relevant to the patient's psychological disorder was induced with a projective test, the meta-contrast technique (MCT). Increased blood flow in the orbital frontal region of the left hemisphere was observed in each of the 11 subjects who showed evidence of experiencing anxiety during the procedure. In a second study four additional anxiety patients were studied with a high-resolution (254-detector)Xe rCBF system. In addition to the anxiety and resting conditions, a neutral verbalization condition was added to control for the verbal aspects of the anxiety induction procedure. The results again showed the experience of anxiety to be accompanied by increased blood flow in the left orbital frontal region, with the patients showing this flow increase to be greater in the posterior, paralimbic, areas of the region. These results are consistent with previous suggestions of left hemisphere involvement in anxiety. They also suggest that imaging methods may allow research into what appears to be exaggerated corticolimbic activity in this disorder.     

Validity and reliability of electroencephalographic frontal alpha asymmetry and frontal midline theta as biomarkers for depression

Electroencephalographic (EEG) frontal alpha asymmetry (FAA) and frontal midline (FM) theta have been suggested as biomarkers for depression and anxiety, but have mostly been assessed in small and non‐clinical studies. In a clinical sample of 79 adults with depression (ICD‐10: F32), resting EEG and scales of depression (MADRS) and anxiety (HADS‐A) were measured at intake and after 3 months. FAA and FM theta values were referenced to a normative population database. Internal consistency, test‐retest reliability, and correlations with psychiatric tests were examined. Reliability was sufficient. However, FAA and FM theta values were close to the general population, and correlations with psychiatric tests were mostly small and non‐significant, with the exception of FAA on F7–F8 z‐scores and HADS‐A. We conclude that the validity of FAA and FM theta and therefore their potential as biomarkers for depression and anxiety remain unclear.     

Progress in Executive-Function Research: From Tasks to Functions to Regions to Networks

ABSTRACT— It has long been observed that damage to the frontal cortex affects a person's ability to control thought, behavior, and emotion while sometimes leaving fundamental processes such as vision, hearing, and long-term memory intact. Such observations have led theoreticians to suppose that a set of executive control functions exists, at the top of the hierarchy of mental processes. To study these executive functions and their relation to the frontal cortex and its subregions, researchers have long employed several now-classic cognitive tests in patients with brain damage. Yet until recently it has proved difficult to reliably localize the putative executive functions to discrete regions. This article illustrates how recent progress in executive-functions research has been driven by the coupling of sophisticated neuroscience techniques with advances in experimental psychology. Taking examples from recent studies, it shows how experimental tasks may be decomposed into cognitive components that can be localized to discrete—but structurally connected—brain regions. What emerges is a new ontology for executive function in terms of which cognitive components exist and of how, and when, they are recruited during task performance.     

Asymmetry and performance: toward a neurodevelopmental theory

Hemispheric asymmetry implies the existence of developmental influences that affect one hemisphere more than the other. However, those influences are poorly understood. One simple view is that asymmetry may exist because of a relationship between a mental process' degree of lateralization and how well it functions. Data scaling issues have largely prevented such investigations, but it is shown that scaling effects are minimized after correction for ceiling and floor effects. After correction, lateralization-performance correlations are pervasive. However, while some correlations are positive, others are negative, with the direction depending on the underlying lateralized process. Two hypotheses are proposed that can account for these relationships by pointing either to individual differences in maturation of the corpus callosum or to developmental limits encountered at different ages of childhood. Their investigation should contribute toward a neurodevelopmental theory of hemispheric asymmetry.     

Is a sigh “just a sigh”? Sighs as emotional signals and responses to a difficult task

Sighing and the interpretation of sighs in everyday life seem never to have been the subject of psychological research. A questionnaire study of sighing showed that people associate sighing mainly with negative, low-intensity and deactivated emotional states. A second study investigated self/other differences in the interpretation of sighs in four hypothetical situations, revealing that sighs in other people are primarily perceived as signs of sadness, whereas own sighs are more often believed to express a state of "giving up" something or somebody. In a third experimental study participants worked on difficult (insoluble) puzzles, which generated many futile solution attempts, often accompanied by sighs. It is concluded that sighs are often unintentional expressions of an activity, plan or desire that has to be discarded, creating a pause before it can be replaced by a novel initiative.     

主、宾关系从句加工不对称性效应及其神经机制

句子加工领域内, 主、宾关系从句加工不对称性效应是诸多语种内普遍存在的一种语言现象。本文对主、宾关系从句加工不对称性效应从如下几个方面进行了分析和论述：①从成人语言、儿童语言和失语症患者三个领域并结合印欧语系和非印欧语系的语言特征, 详细分析了该效应及其普遍性和特殊性; ②主、宾关系从句加工不对称性效应的理论解释：句法角色理论、“填充语-空位”依附理论、积极填充策略、名词短语可及性层级理论和干扰相似性理论; ③与主、宾关系从句加工不对称性效应有关的脑电成分及相应的脑区激活模式的分析。最后, 在对已有理论评价分析的基础上, 提出“标记浮动”句子加工理论模型, 并指出该领域未来的研究方向。     

不同任务类型对熟练维汉双语者跨语言启动不对称性的影响

采用两种不同的任务类型对熟练维汉双语者跨语言掩蔽翻译启动效应进行考察,结果发现,在词汇决定任务中,熟练维汉双语者在L1-L2和L2-L1两个方向上均表现出了掩蔽翻译启动效应,但L1-L2方向远大于L2-L1方向,即掩蔽翻译启动效应具有不对称性。而在语义分类任务中,熟练维汉双语者在两个方向上表现出的翻译启动效应量相近,具有对称性。结果支持Kroll的修正层级模型。