The role of white matter hyperintensities and medial temporal lobe atrophy in age-related executive dysfunctioning

Various studies support an association between white matter hyperintensities (WMH) and deficits in executive function in nondemented ageing. Studies examining executive functions and WMH have generally adopted executive function as a phrase including various functions such as flexibility, inhibition, and working memory. However, these functions include distinctive cognitive processes and not all may be affected as a result of WMH. Furthermore, atrophy of the medial temporal lobe (MTA) is frequently observed in ageing. Nevertheless, in previous studies of nondemented ageing MTA was not considered when examining a relationship between white matter and executive function. The goal of the present study was to examine how WMH and MTA relate to a variety of executive functions, including flexibility, fluency, inhibition, planning, set shifting, and working memory. Strong correlations were observed between WMH and MTA and most of the executive functions. However, only MTA was related to flexibility and set shifting performance. Regression analysis furthermore showed that MTA was the strongest predictor of working memory, after which no further significant association with WMH was noted. Alternatively, both MTA and periventricular hyperintensities independently predicted inhibition performance. These findings emphasize the importance of MTA when examining age-related decline in executive functioning.     

不同时间的睡眠剥夺对执行功能的影响

睡眠剥夺在日常生活工作中广泛存在,执行功能指需要很多认知过程参与,以使操作优化的机制.目前有关睡眠剥夺对认知功能的影响关注于对执行功能的影响,但是尚没有不同时间睡眠剥夺后执行功能情况的研究,并且研究缺乏系统.本研究应用卡片分类测验、词汇流畅性测验究了32名青年男性在不同睡眠剥夺条件下(睡眠剥夺21h、睡眠剥夺45h、睡眠剥夺69h、正常对照组)的执行功能情况.结果表明:睡眠剥夺后执行功能下降,同剥夺时间有一定关系,45h后下降显著.     

Evolutionary neurology,responsive equilibrium,and the moral brain

The relation between morality and the brain is a topic usefully examined through the evolutionary neurology of John Hughlings-Jackson, who considered higher mental function to be progressively inclusive integration of sensori-motor processes. His view, based on careful observations of patients with neurological disorders, implies that moral reasoning involves integration and coordination of behaviour through a process of representation and re-representation encompassing broader and broader types of information sensitive to environmental contingencies. The relevant information is processed in diverse brain areas: superior temporal sulcus (STS), inferior parietal lobule (IPL), inferior frontal gyrus (IFG), dorsolateral prefrontal (DLPF) areas, as well as anterior temporal (AT) structures. Moral function can be regarded as maximally integrating emotion, social cognition, and other-regarding sensibilities using propositionally organised cognitive structures that map a shared world of human activity and relationships so that they take account of what in social and personal life counts as something.     

Distracted by relatives: Effects of frontal lobe damage on semantic distraction

When young adults carry out visual search, distractors that are semantically related, rather than unrelated, to targets can disrupt target selection (see 2 and 22). This effect is apparent on the first eye movements in search, suggesting that attention is sometimes captured by related distractors. Here we assessed effects of semantically related distractors on search in patients with frontal-lobe lesions and compared them to the effects in age-matched controls. Compared with the controls, the patients were less likely to make a first saccade to the target and they were more likely to saccade to distractors (whether related or unrelated to the target). This suggests a deficit in a first stage of selecting a potential target for attention. In addition, the patients made more errors by responding to semantically related distractors on target-absent trials. This indicates a problem at a second stage of target verification, after items have been attended. The data suggest that frontal lobe damage disrupts both the ability to use peripheral information to guide attention, and the ability to keep separate the target of search from the related items, on occasions when related items achieve selection.     

Various shrug exercises can change scapular kinematics and scapular rotator muscle activities in subjects with scapular downward rotation syndrome

Scapular dyskinesis, characterized by scapular downward rotation syndrome (SDRS) affects scapula-humeral rhythm and results in shoulder dysfunction. Previous study has led to the recommendation of standard shrug exercise to contend with SDRS and strengthen the upper trapezius (UT) muscle. However, few researchers have examined which shrug exercise is most effective. The aim of this research was to compare scapular kinematic changes and scapular rotator muscles activity across three different shrug exercises in SDRS. The amounts of scapular downward rotation were measured by a caliper and the scapular upward rotation angle was measured using two digital inclinometers. Surface electromyography was used to measure EMG amplitude from the UT, lower trapezius (LT), serratus anterior (SA), and levator scapula (LS). Seventeen subjects with SDRS were recruited for this study. The subjects performed three shrug exercises with 30° shoulder abduction (preferred shrug, frontal shrug, and stabilization shrug). The stabilization shrug showed a significantly greater scapular upward rotation angle compared with the preferred shrug (P = 0.004) and frontal shrug (P = 0.006). The UT activity was significantly greater in the frontal shrug than in the preferred shrug (P = 0.002). The UT/LS muscle activity ratio was also significantly greater in the frontal shrug than in the preferred shrug (P = 0.004). The stabilization shrug should be preferred to enhance the upward rotation angle. In addition, the frontal shrug can be used as an effective method to increase UT activity and to decrease LS activity in SDRS.     

On historical consciousness: A pilot investigation

Philosophers of history posit a class of concepts known as colligatory concepts that contribute to historical consciousness and that refer specifically to historical events. Although analysis has identified colligatory concepts in historical discourse, these concepts have not yet been investigated empirically. We present a new methodology for studying these concepts and historical consciousness more broadly, as well as pilot data supporting the methodology. Our aim in the pilot study was to establish whether colligatory concepts are processed differently from control concepts when subjects are asked to judge historical statements. We compared judgments of colligatory concepts in healthy participants and in a patient group with impaired working memory cognitive processing capacity. Forty healthy, college-educated participants and 25 patients with Parkinson's disease were asked to rate narrative sentences containing historical content and an equal number of identically constructed narrative sentences of equal length but devoid of historical content. All participants rated their pre-test interest in history as relatively low (mean 5 out of 7). Though no group differences emerged, historical sentences were judged by both groups (total N = 65) to be significantly different from non-historical sentences across dimensions of interestingness, meaningfulness, likeability, complexity, thought provoking-ness, and truth content. Interestingly, historical sentences were judged to be truer than control sentences even though participants were not interested in and presumably knew little about history. The neurocognitive system appears to process sentences with historical content separately from sentences without historical content. The methodology described here appears to be a valid approach for study of processing of historical content of sentences.     

前瞻性记忆的生理基础

中国科学院心理研究所,北京 100101     

Bilateral comparison of occipital lobe sulci: A sulcus identifying algorithm

A procedure for automatic identification of sulci of cerebral hemispheres in magnetic resonance images is presented. The algorithm departs from information of the spatial location of a given feature (e.g., sulcal contour) in one hemisphere and automatically defines its course in the other hemisphere. The automatic tracing of sulci was successfully performed in the mesial aspect both hemispheres in 18 normal individuals. The sulcal location in the target hemisphere was first approximated by assuming an affine transformation between hemispheres, and then refined by local edge analysis. The method produced reliable results in comparing the intersulcal areas (the cuneus), sulcal length, their complexity, and the angle between the pariteooccipital and retrocalcarine fissures.     

Working memory impairment in people with Williams syndrome: Effects of delay, task and stimuli

Williams syndrome (WS) is a neurodevelopmental disorder associated with impaired visuospatial representations subserved by the dorsal stream and relatively strong object recognition abilities subserved by the ventral stream. There is conflicting evidence on whether this uneven pattern in WS extends to working memory (WM). The present studies provide a new perspective, testing WM for a single stimulus using a delayed recognition paradigm in individuals with WS and typically developing children matched for mental age (MA matches). In three experiments, participants judged whether a second stimulus ‘matched’ an initial sample, either in location or identity. We first examined memory for faces, houses and locations using a 5 s delay (Experiment 1) and a 2 s delay (Experiment 2). We then tested memory for human faces, houses, cat faces, and shoes with a 2 s delay using a new set of stimuli that were better controlled for expression, hairline and orientation (Experiment 3). With the 5 s delay (Experiment 1), the WS group was impaired overall compared to MA matches. While participants with WS tended to perform more poorly than MA matches with the 2 s delay, they also exhibited an uneven profile compared to MA matches. Face recognition was relatively preserved in WS with friendly faces (Experiment 2) but not when the faces had a neutral expression and were less natural looking (Experiment 3). Experiment 3 indicated that memory for object identity was relatively stronger than memory for location in WS. These findings reveal an overall WM impairment in WS that can be overcome under some conditions. Abnormalities in the parietal lobe/dorsal stream in WS may damage not only the representation of spatial location but may also impact WM for visual stimuli more generally.     

The Wisconsin Card Sorting Test and the cognitive assessment of prefrontal executive functions: A critical update

For over four decades the Wisconsin Card Sorting Test (WCST) has been one of the most distinctive tests of prefrontal function. Clinical research and recent brain imaging have brought into question the validity and specificity of this test as a marker of frontal dysfunction. Clinical studies with neurological patients have confirmed that, in its traditional form, the WCST fails to discriminate between frontal and non-frontal lesions. In addition, functional brain imaging studies show rapid and widespread activation across frontal and non-frontal brain regions during WCST performance. These studies suggest that the concept of an anatomically pure test of prefrontal function is not only empirically unattainable, but also theoretically inaccurate. The aim of the present review is to examine the causes of these criticisms and to resolve them by incorporating new methodological and conceptual advances in order to improve the construct validity of WCST scores and their relationship to prefrontal executive functions. We conclude that these objectives can be achieved by drawing on theory-guided experimental design, and on precise spatial and temporal sampling of brain activity, and then exemplify this using an integrative model of prefrontal function [i.e., Miller, E. K. (2000). The prefrontal cortex and cognitive control. Nature Reviews Neuroscience, 1, 59–65.] combined with the formal information theoretical approach to cognitive control [Koechlin, E., & Summerfield, C. (2007). An information theoretical approach to prefrontal executive function. Trends in Cognitive Sciences, 11, 229–235.].