Contemporary theories of 1/f noise in motor control

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.     

Default-mode network functional connectivity in aphasia: Therapy-induced neuroplasticity

Previous research on participants with aphasia has mainly been based on standard functional neuroimaging analysis. Recent studies have shown that functional connectivity analysis can detect compensatory activity, not revealed by standard analysis. Little is known, however, about the default-mode network in aphasia. In the current study, we studied changes in the default-mode network in subjects with aphasia who underwent semantic feature analysis therapy. We studied nine participants with chronic aphasia and compared them to 10 control participants. For the first time, we identified the default-mode network using spatial independent component analysis, in participants with aphasia. Intensive therapy improved integration in the posterior areas of the default-mode network concurrent with language improvement. Correlations between integration and improvement did not reach significance, but the trend suggests that pre-therapy integration of the default-mode network may predict therapy outcomes. Functional connectivity allows a better understanding of the impact of semantic feature analysis in aphasia.     

Publication Ethics in Biomedical Journals from Countries in Central and Eastern Europe

Publication ethics is an important aspect of both the research and publication enterprises. It is particularly important in the field of biomedical science because published data may directly affect human health. In this article, we examine publication ethics policies in biomedical journals published in Central and Eastern Europe. We were interested in possible differences between East European countries that are members of the European Union (Eastern EU) and South-East European countries (South-East Europe) that are not members of the European Union. The most common ethical issues addressed by all journals in the region were redundant publication, peer review process, and copyright or licensing details. Image manipulation, editors’ conflicts of interest and registration of clinical trials were the least common ethical policies. Three aspects were significantly more common in journals published outside the EU: statements on the endorsement of international editorial standards, contributorship policy, and image manipulation. On the other hand, copyright or licensing information were more prevalent in journals published in the Eastern EU. The existence of significant differences among biomedical journals’ ethical policies calls for further research and active measures to harmonize policies across journals.     

Work-family balance and energy: A day-level study on recovery conditions

The present study examines whether daily recovery inhibiting and enhancing conditions predict day-levels of work-family conflict (WFC), work-family facilitation (WFF), exhaustion and vigor. Forty-nine individuals from various professional backgrounds in Spain provided questionnaire and daily survey measures over a period of five working days. Multilevel analyses showed that day-levels of work pressure and recovery after breaks at work significantly predicted WFC and exhaustion, and WFF and vigor, respectively. Moreover, daily fluctuations in expression of emotions had different effects depending on the expressed content (negative or positive) and the setting where it took place (work or home). Furthermore, additional analyses provided some evidence for a moderating role of expression of emotions at work on the relationship between recovery inhibiting and enhancing conditions and exhaustion. These findings reveal practical implications for individuals and organizations and suggest possible avenues for future research.     

The global precedence effect is not affected in inhibition of return

This study assessed whether inhibitory processes occurring in IOR affect perceptual processing of hierarchically organised stimuli. Experiment 1 used a global/local task that presented stimuli to the left or the right side. Results showed a global task advantage and a larger interference in the local than in the global task—the global precedence effect (GPE). These effects were larger than in previous studies using centrally presented stimuli, which suggests a greater involvement of low spatial frequency analysis with peripheral than with central stimuli. Experiment 2 combined the global/local task with IOR. Results replicated those of Experiment 1 but there was no interaction with stimulus location. That is, the GPE was not affected in IOR. Thus, we conclude that the GPE and inhibitory processing occurring in IOR are subserved by different mechanisms.     

Sex differences in visuospatial ability: Do performance factors play such an important role?

This study was designed to analyze some performance factors as a possible source of sex-related bias in psychometric tests of visuospatial aptitude. Goldstein, Haldane, and Mitchell (1990) explored the effect of two response styles—slowness of performance and reluctance to guess—by using a 3-D mental rotation test (the task showing the largest cognitive sex difference) and found that time limits and raw scores contributed substantially to the male advantage. We applied two tests in thespeed-power continuum to a representative sample of 621 males and 821 females in their last year of high school in a 2 × 2 (gender × time) full factorial design. Reluctance to guess was similar for males and females. Males obtained more correct responses on both tests, and for both time conditions, than did females. These results are not only statistically significant but also are of substantial practical consequence.     

Human biological and nonbiological point-light movements: Creation and validation of the dataset

Human action perception is so powerful that people can identify movement efficiently in the absence of pictorial information, such as in point-light displays. Interest is growing in this type of stimulus for research in neuroscience. This interest stems from the advantage of separating the component of pure human action kinematics from other pictorial information, such as facial expression and muscle contraction. Although several groups have previously developed datasets of human point-light actions, due to the lack of datasets composed of daily actions with short durations, we developed 20 biological and 40 control (scrambled) point-light movements by using the technique of recording people wearing reflector patches. The videos are about 1 s long. Subsequently, we performed a judgment task in which 100 participants (50 male and 50 female) evaluated each video according to three categories: human action resemblance, performed action, and gender of actor. We present the mean scores of each evaluation for each video, and further propose a selection of the most suitable videos to be used as human point-light action displays and scrambled point-light displays for control. Finally, we discuss our findings on the gender attributions of the point-light displays.