High neuromagnetic activation in the left prefrontal and frontal cortices correlates with better memory performance for abstract words

The ability to store and manipulate online information may be enhanced by an inner speech mechanism that draws upon motor brain regions. Neural correlates of this mechanism were examined using event-related functional magnetic resonance imaging (fMRI). Sixteen participants completed two conditions of a verbal working memory task. In both conditions, participants viewed one or two target letters. In the “storage” condition, these targets were held in mind across a delay. Then a probe letter was presented, and participants indicated by button press whether the probe matched the targets. In the “manipulation” condition, participants identified new targets by thinking two alphabetical letters forward of each original target (e.g., f → h). Participants subsequently indicated whether the probe matched the newly derived targets. Brain activity during the storage and manipulation conditions was examined specifically during the delay phase in order to directly compare manipulation versus storage processes. Activations that were common to both conditions, yet disproportionately greater with manipulation, were observed in the left inferior frontal cortex, premotor cortex, and anterior insula, bilaterally in the parietal lobes and superior cerebellum, and in the right inferior cerebellum. This network shares substrates with overt speech and may represent an inner speech pathway that increases activity with greater working memory demands. Additionally, an inverse correlation was observed between manipulation-related brain activity (on correct trials) and test accuracy in the left premotor cortex, anterior insula, and bilateral superior cerebellum. This inverse relationship may represent intensification of inner speech as one struggles to maintain performance levels.     

Forgetting the unforgotten affective autobiographical memories in nonclinical dissociators

Inefficient memory inhibition has been observed in nonclinical and clinical dissociators. Paradoxically, dissociators also report unusual forgetfulness. Investigating how forgetting emerges in dissociators may uncover the antecedents for their self-report memory problems. We postulated that set switch can link inefficient memory inhibition to forgetting. Recollection detour, which involves an affect switch, may elicit forgetting of previously uninhibited memories in nonclinical dissociators. This hypothesis was verified in participants with high- and low-dissociation proneness via a retrieval practice paradigm using positive and negative autobiographical memories. After the study and retrieval-practice phases, memories of the practiced affect category were tested without and with intervening recall of the unpracticed affect category in the control and detour condition, respectively. Nondissociators showed reduced recall in the control condition, replicating the retrieval-induced forgetting (RIF) effect and recollection detour did not alter the RIF effect. By contrast, nonclinical dissociators showed the RIF effect in the detour condition but not in the control condition. Detour to recollecting memories of another affect category rendered an aftereffect of forgetting of previously uninhibited memories in nonclinical dissociators. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

With or without a hole: young infants' sensitivity for topological versus geometric property

Evidence from adult psychophysics, brain imaging, and honeybee's behaviour has been reported to support the notion that topological properties are the primitives of visual representation (Chen, 1982 Science 218 699-700). Here, we ask how the sensitivity to topological property might originate during development. Specifically, we tested 1.5- to 6-month-old infants' visual sensitivity for topological versus geometric properties with the forced-choice novelty preference technique. A disk and a ring were used in the topologically different condition (experiment 1), while a disk and a triangle were used in the geometrically different condition (experiment 2). Spontaneous preferences for the disk, the ring, and the triangle were measured pairwise using the preferential looking-time technique (experiment 3). The results showed that infants could reliably discriminate stimuli based on topological differences, but failed to do so with geometric differences. Moreover, in the generalisation task, infants showed higher novelty preference for the topologically different figure (the ring). In addition, the results of both experiments cannot be attributed to a spontaneous preference for the ring or for the disk. Further analysis on individual infants' age and performance revealed two distinct developmental trends. Infants seem to be sensitive to topological differences as young as 1.5 months, while their ability to discriminate geometric differences was at chance before 3 months and gradually improved with age. Taken together, our findings suggested an early sensitivity for topological property, at least for the detection of stimuli with or without a hole.     

大学生网络使用动机对其病理性网络使用行为的影响机制

基于以往病理性网络使用行为成因的研究,本研究提出并检验了病理性网络使用行为作用机制的三个假设模型。结果表明：人际关系困扰、自尊、情感型网络使用动机均与病理性网络使用行为有显著相关;其中,人际关系困扰对个体病理性网络使用行为具有直接影响,也通过情感获取型网络动机间接影响病理性网络使用行为;而自尊则主要通过作用于人际关系困扰和情感获取型网络动机间接地影响病理性网络使用行为。情感型网络使用动机是个体病理性网络使用行为形成机制中的关键性因素。     

Physiological and psychological impacts on male medical interns during on-call duty

This study aimed to explore the physiological and psychological impacts on male medical interns during on-call duty (OCD). A prospective study of 13 medical interns was carried out using repeated testing during an on-call internal medicine and a duty-free course. There are 10 OCDs per month and each duty is composed of 33.5 consecutive work hours followed by 2 duty-free days for a time period of 3 months. Spectral analysis of R-R intervals was performed to evaluate the participants' heart rate variability. Among the three main spectral components distinguished, a high-frequency (HF) component of 0.15-0.4 Hz and a low-frequency component (LF) of 0.04-0.15 Hz were analyzed. The ratio of LF and HF (LF/HF) was also calculated. Reduced LF/HF, which suggests reduced cardiac sympathetic modulation, was found during duty night work. Increased HF was identified during the first sleep after OCD, which corresponded to the sleepiness scales. The OCD causes temporary emotional influence by the findings of higher anxiety and depression scores. In addition, inattention and impulsiveness, as represented by the continuous performance test score and lower nocturnal sympathetic modulation, were found, which indicated the differences between the internal medicine course and duty-free course. Our study suggests that 10 stressful on-call duties monthly result in reduced sympathetic modulation during duty night work, high anxiety and depression state, and a persistent inattention.     

On the regress problem of deciding how to decide

Any decision is made in some way or another. Which way? (Have I worked out enough alternatives to choose from? Which decision rule to apply?) That is a higher-order decision problem, to be dealt with in some way or other. Which way? That is an even higher-order decision problem. There seems to be a regress of decision problems toward higher and higher orders. But in daily life we stop moving to higher-order decision problems—stop the regress—at some finite point. The regress problem of deciding how to decide is the problem of explaining what would make it rational to stop the regress. I will give a new solution in the present paper. The result suggests a new way of looking at standard Bayesian theory and the more recent theory of adaptive rationality.     

Dynamic deformation of shape-memory alloys: Evidence of domino detwinning?

Deformation of NiTi shape-memory alloys (SMAs) under dynamic tension has been studied. It is found that the stress plateau associated with detwinning still exists at the highest strain rate tested (300s -1 ). Beyond the stress plateau, when dislocation mechanisms dominate the deformation process, the strain-hardening effect is more strongly dependent on strain rate. The dynamically deformed specimens exhibit a shape-recovery process and a two-way memory effect which are identical with that for the alloy deformed under quasistatic conditions. The observations suggest that the detwinning process takes place in SMAs under dynamic tension.     

Study on the damping behaviour of eutectic high-entropy alloys with lamellar structures

ABSTRACT

Damping is the ability to reduce the energy produced by vibrations in a system. In this research, the eutectic high-entropy alloys (EHEAs), AlCo_xCrFeNi_2.1 (x?=?0.7, 1.0 and 1.5), are firstly studied for their damping behaviour. EHEA is a promising concept of high-entropy alloys. By combining the advantages of eutectic phases and HEAs, the EHEAs show better liquidity, castability and compositional homogeneity than conventional HEAs. Meanwhile, it can strike a great balance in mechanical strength and tensile ductility owing to the lamellar structures. The microstructures and crystal structure of two near-EHEAs are also studied. AlCo_0.7CrFeNi_2.1 is a hypo-eutectic HEA with primary body-centred cubic phases. AlCo_1.5CrFeNi_2.1 is a hyper-eutectic HEA with primary face-centred cubic phases. The results showed that these eutectic and near-eutectic alloys gave rise to greater tan δ values than conventional dual-phase HEAs, which might be attributed to their lamellar structures.     

Reflexively mindblind: Using theory of mind to interpret behavior requires effortful attention

People commonly interpret others’ behavior in terms of the actors’ underlying beliefs, knowledge, or other mental states, thereby using their “theory of mind.” Two experiments suggest that using one’s theory of mind is a relatively effortful process. In both experiments, people reflexively used their own knowledge and beliefs to follow a speaker’s instruction, but only effortfully used their theory of mind to take into account a speaker’s intention to interpret those instructions. In Experiment 1, people with lower working memory capacity were less effective than people with larger working memory capacity in applying their theory of mind to interpret behavior. In Experiment 2, an attention-demanding secondary task reduced people’s ability to apply their theory of mind. People appear to be reflexively mindblind, interpreting behavior in terms of the actor’s mental states only to the extent that they have the cognitive resources to do so.