Walking impairs cognitive performance among people with multiple sclerosis but not controls

People with multiple sclerosis (MS) complain of problems completing two tasks simultaneously; sometimes called ‘dual-tasking’ (DT). Previous research in DT among people with MS has focused on how adding a cognitive task interferes with gait and few have measured how adding a motor task could interfere with cognition. We aimed to determine the extent to which walking affects a concurrent working memory task in people with MS compared to healthy controls. We recruited MS participants (n = 13) and controls (n = 10) matched by age (±3 years), education (±3 years) and gender. Participants first completed the cognitive task (subtracting 7’s from the previous number) and then again while walking on an instrumented walkway. Although there were no baseline differences in cognition or walking between MS participants and controls, MS participants demonstrated a 52% decrease in number of correct answers during DT (p < 0.001). Mental Tracking Rate (% correct answers/min) correlated strongly with MS-related disability measured using the Expanded Disability Status Scale (EDSS; r(11) = −0.68, p < 0.01). We propose that compromised mental tracking during walking could be related to limited neural resource capacity and could be a potentially useful outcome measure to detect ecologically valid dual tasking impairments.     

Influence of bidirectional perspective on learning routes and spatial layout

The capacity to remain spatially oriented is an essential function in our day to day lives and it seems that the form in which we acquire the spatial information affects the way in which the spatial knowledge is represented in our memory. The goal of this research was to investigate whether the acquisition of spatial information through the learning of three routes within an immersive environment was improved or impaired when participants have access to the backward perspective in addition to the forward perspective. Results, both in reproduction and drawing tasks, showed a poorer performance of the bidirectional group maybe due to the extra-effort involved in updating the spatial information trial by trial. However it seems that the experience enhanced the performance of the bidirectional group in one respect, as they were able to reduce significantly the number of error directions in the last path.     

负性情绪背景和延迟对时间性前瞻记忆的影响

采用2（情绪效价：负性、中性）×2（延迟设置：无延迟、有延迟）的实验设计,探究负性情绪对时间性前瞻记忆的干扰效应。结果显示在无延迟条件下,负性情绪组的前瞻记忆成绩差于中性情绪组,负性情绪组的总时间监控次数和监控后期的时间监控次数均少于中性情绪组;在有延迟条件下,负性情绪组的前瞻记忆成绩和监控后期的时间监控次数与中性情绪组均无差异。结果说明负性情绪会干扰时间性前瞻记忆,而延迟可以消除这种干扰效应。     

Executive functions and linguistic performance in SCD older adults and healthy controls

Subjective cognitive decline (SCD) might represent the preclinical phase of Alzheimer’s disease. Given the interest to characterize it, the present study explores (1) if there are differences in lexical retrieval (LexR) and sentence comprehension (SComp) between SCD and matched controls, and (2) the predictive value of demographic variables and executive functions in relation to LexR and SComp in each group. A sample of 135 participants voluntarily took part in this study (66 with SCD). They all completed the Trail Making, the Stroop, the Boston Naming, and the ECCO-Senior tests, as well as verbal fluency tasks (VF). Results show that (1) groups differ in LexR and in inhibition efficiency, and (2) VF is explained by years of formal education, particularly in the control group; SComp in the most complex items seems to rely in different strategies, related to flexibility in controls and to inhibition efficiency in SCD patients.     

No evidence for a role of reconsolidation in updating of paired associates

Reconsolidation theory states that memories are labilized through reactivation, making them prone to change, before being re-consolidated. When information in memory requires updating, reconsolidation theory therefore predicts that reminders of previously learned information should facilitate updating of that information and should thus improve memory for the updated information. In two experiments, we tested this prediction by investigating memory for word pairs over a short time-scale. Participants studied word pairs (A–B), some of which were subsequently updated with word pairs that shared the first word (A–C). Half of the A–C pairs received a pre-study reminder of the first word in the pair so as to reactivate and labilize A–B memory. In a recognition memory test targeting the A–C list, reminders by and large had no effect on memory. Results thus failed to support the predictions of reconsolidation theory.     

Activation of semantic information at the sublexical level during handwriting production: Evidence from inhibition effects of Chinese semantic radicals in the picture‐word interference paradigm

Using a non‐alphabetic language (e.g., Chinese), the present study tested a novel view that semantic information at the sublexical level should be activated during handwriting production. Over 80% of Chinese characters are phonograms, in which semantic radicals represent category information (e.g., 椅 ‘chair,’ 桃 ‘peach,’ 橙 ‘orange’ are related to plants) while phonetic radicals represent phonetic information (e.g., 狼 ‘wolf,’ 朗 ‘brightness,’ 郎 ‘male,’ are all pronounced /lang/). Under different semantic category conditions at the lexical level (semantically related in Experiment 1; semantically unrelated in Experiment 2), the orthographic relatedness and semantic relatedness of semantic radicals in the picture name and its distractor were manipulated under different SOAs (i.e., stimulus onset asynchrony, the interval between the onset of the picture and the onset of the interference word). Two questions were addressed: (1) Is it possible that semantic information could be activated in the sublexical level conditions? (2) How are semantic and orthographic information dynamically accessed in word production? Results showed that both orthographic and semantic information were activated under the present picture‐word interference paradigm, dynamically under different SOAs, which supported our view that discussions on semantic processes in the writing modality should be extended to the sublexical level. The current findings provide possibility for building new orthography‐phonology‐semantics models in writing.     

The Generalized Quantum Episodic Memory Model

Recent evidence suggests that experienced events are often mapped to too many episodic states, including those that are logically or experimentally incompatible with one another. For example, episodic over‐distribution patterns show that the probability of accepting an item under different mutually exclusive conditions violates the disjunction rule. A related example, called subadditivity, occurs when the probability of accepting an item under mutually exclusive and exhaustive instruction conditions sums to a number >1. Both the over‐distribution effect and subadditivity have been widely observed in item and source‐memory paradigms. These phenomena are difficult to explain using standard memory frameworks, such as signal‐detection theory. A dual‐trace model called the over‐distribution (OD) model (Brainerd & Reyna, 2008) can explain the episodic over‐distribution effect, but not subadditivity. Our goal is to develop a model that can explain both effects. In this paper, we propose the Generalized Quantum Episodic Memory (GQEM) model, which extends the Quantum Episodic Memory (QEM) model developed by Brainerd, Wang, and Reyna (2013). We test GQEM by comparing it to the OD model using data from a novel item‐memory experiment and a previously published source‐memory experiment (Kellen, Singmann, & Klauer, 2014) examining the over‐distribution effect. Using the best‐fit parameters from the over‐distribution experiments, we conclude by showing that the GQEM model can also account for subadditivity. Overall these results add to a growing body of evidence suggesting that quantum probability theory is a valuable tool in modeling recognition memory.     

从反义RNA到RNA干扰:科学突破的机遇与创新

RNA干扰是近年发现的存在于真核细胞内的一种重要防御机制,现已发展成为一种全新的基因阻断技术,广泛用于抗病毒、抗肿瘤和后基因组时代基因功能研究.它是在反义RNA研究中意外获得的重大科学突破,其发现过程对科学研究有重要启示意义.     

Integration versus separation in Stroop‐like counting interference tasks1

Abstract: Two versions of a Stroop‐like counting interference task were compared to examine how irrelevant information is ignored. In the integrated task, participants enumerated digits (inconsistent condition) or letters (neutral condition) while attempting to ignore the identity of the characters. In the newly created separated task, participants enumerated asterisks while attempting to ignore a single digit (inconsistent condition) or letter (neutral condition) at fixation. Interference (longer responses in the inconsistent condition than in the neutral condition) was small but significant in both tasks but was not reduced by separation. Contrasted with the pattern in the color–word Stroop task, these results suggest that dimensional separation has different effects on interference depending on the overall amount of interference.