Interlimb coordination following stroke

Studies investigating whether simultaneous bilateral movements can facilitate performance of the impaired limb(s) of stroke patients have returned mixed results. In the present study we compared unilateral limb performance (amplitude, cycle duration) with performance during an interlimb coordination task involving both homologous (both arms, both legs) and non-homologous (one arm, one leg) limbs in stroke participants (n=7) and healthy age-matched controls (n=7). In addition, the effect of on-line augmented visual feedback on interlimb coordination was investigated. Participants performed cyclical flexion-extension movements of the arms and legs in the sagittal plane paced by an auditory metronome (1 Hz). Movement amplitudes were larger and cycle durations shorter during homologous limb coordination than non-homologous coordination. Compared with unilateral movements both groups had reduced movement amplitudes and the stroke group increased cycle duration when interlimb coordination tasks were performed. These effects were most evident during non-homologous (arm and leg) coordination. No evidence of facilitation of the impaired limb(s) was found in any of the interlimb coordination conditions. Augmented visual feedback had minimal effect on the movements of control participants but lead to an increase of cycle duration for stroke participants.     

The locus of adaptation to altered gain in aimed movements

Altered gain settings cause a mismatch between the actual movement amplitude across the surface and the distance covered on a real time visual display. The present study pursued three objectives of how adaptation to altered gain affects aimed motor behavior. First, we replicated findings of an earlier study reporting a negative linear relation between gain and both target acquisition time and end-point variability. This means that our data do not agree with the classic U-shaped relation between gain and acquisition time. Second, our results proved to be robust when we manipulated movement difficulty by varying target distance. And third, dividing a movement into four successive sections on the basis of key kinematic events revealed the locus of the adaptation to altered gain within movement execution. Time differences between gain conditions proved to start at a very early part of the movement, but appeared to be absent in the final movement section. In contrast, differences between gain conditions regarding the use of online feedback were also present in the last part of the movement during which the final target approach takes place.     

Comparison of fundus autofluorescence and minimum-motion measurements of macular pigment distribution profiles derived from identical retinal areas

The optical density of macular pigment was measured at twelve retinal locations in ten subjects by minimum motion photometry, comparing 460 nm with 580 nm or 550 nm. Fundus autofluorescence images were obtained for the same subjects with a scanning laser ophthalmoscope. Optical density was computed from mean calibrated grey-scale values for a central circular field and for annular segments, identical to areas tested psychophysically, and for complete annuli. Psychophysical assessments of optical density were similar irrespective of whether 550 nm or 580 nm was used. Optical density values derived psychophysically showed a linear correlation with assessments based on identical sampled areas of annular segments (slope = 0.98, r2 = 0.97) or complete annuli (slope = 0.89, r2 = 0.96) in autofluorescence images.     

Context in selection of men and women in hiring decisions: gender composition of the applicant pool

The hypothesis that the sex composition of an applicant pool affects the hiring probabilities of individual job applicants was tested using gender-distinctive information on accepted and rejected job applicants in The Netherlands. The evidence supports this hypothesis, although the effect sizes are moderate. Both men and women have a lower probability of being hired when the applicant pool contains fewer applicants from their own sex.     

Relationships of Functional Flexibility with Individual and Work Factors

To investigate how functional flexibility is related to demographics, personality traits, and work perceptions, 250 employees of a large Dutch passenger transport firm filled out a written questionnaire. Two dimensions of functional flexibility were discerned: willingness and ability to be flexible. Analysis of variance showed the support staff and managers were higher on willingness and ability to be flexible than workers. Hierarchic regression analysis showed that willingness to be flexible was positively related to initiative and trust in management, and was negatively related to age and task formalization. Ability to be flexible was positively related to general self-efficacy and initiative, and was negatively related to task formalization. It was concluded that willingness to be flexible depends on fair treatment and freedom provided by their organization and that ability to be flexible is part of the development of general self-efficacy.     

Rewarding leadership and fair procedures as determinants of self-esteem

In the present research, the authors examined the effect of procedural fairness and rewarding leadership style on an important variable for employees: self-esteem. The authors predicted that procedural fairness would positively influence people's reported self-esteem if the leader adopted a style of rewarding behavior for a job well done. Results from a scenario experiment, a laboratory experiment, and an organizational survey indeed show that procedural fairness and rewarding leadership style interacted to influence followers' self-esteem, such that the positive relationship between procedural fairness and self-esteem was more pronounced when the leadership style was high in rewarding behavior. Implications in terms of integrating the leadership and procedural fairness literature are discussed.     

Lost in the wilderness: terror management, action orientation, and nature evaluation

The authors propose that wilderness is intrinsically associated with death, and, consequently, terror management concerns may promote more negative evaluations of wilderness. Consistent with this, wilderness inspired more thoughts about death than either cultivated nature or urban environments (Study 1), and death reminders reduced perceived beauty of wilderness (Study 2). The authors further suggest that active self-regulation facilitates suppression of the dark side of wilderness. Consistent with this, action orientation was positively related to perceived beauty of wilderness (Study 3), and after viewing wilderness, action-oriented individuals were more efficient at suppressing the association between wilderness and death than state-oriented individuals (Study 4). Direct death reminders overruled the effects of action orientation on nature evaluation (Study 5), presumably because direct death reminders are difficult to suppress even for action-oriented individuals.     

Lack of the metabotropic glutamate receptor subtype 7 selectively modulates Theta rhythm and working memory

Metabotropic glutamate receptors (mGluRs) are known to play a role in synaptic plasticity and learning. We have previously shown that mGluR7 deletion in mice produces a selective working memory (WM) impairment, while other types of memory such as reference memory remain unaffected. Since WM has been associated with Theta activity (6-12 Hz) in EEGs, and since EEG abnormalities have been observed in these mice before, we studied the effect of mGluR7 gene ablation on EEG activity in the hippocampus, in particular in the Theta range, during performance of a WM task. In an eight-arm maze with four arms baited, mGluR7 knock-out (KO) and wild-type mice committed the same number of reference memory errors, whereas KOs committed more WM errors. While performing the task, KO mice showed substantially higher Theta amplitudes, and the ratio of Theta to overall EEG power was much increased. No change was seen in the Delta (0-5 Hz), or Gamma (30-40 Hz) EEG bands compared with controls. When recording EEGs during periods of rest in the home cages, no difference was seen between groups. These findings suggest that mGluR7 is important for modulation and control of Theta activity. Since only WM was affected, and only the Theta range of EEG activity was altered, these results show a correlation between Theta rhythm and WM performance, and therefore support the concept that Theta activity in the hippocampus is involved in WM storage.     

An evaluation of the Tripartite Influence Model of body dissatisfaction and eating disturbance with adolescent girls

The Tripartite Influence Model of body image and eating disturbance proposes that three formative influences (peer, parents, and media) affect body image and eating problems through two mediational mechanisms: internalization of the thin-ideal and appearance comparison processes. The current study evaluated this model in a sample of 325 sixth through eighth grade girls. Simple path analyses indicated that internalization and comparison fully mediated the relationship between parental influence and body dissatisfaction and partially mediated the relationship between peer influence and body dissatisfaction. Additionally, internalization and comparison partially mediated the relationship between media influence and body dissatisfaction. Six a priori SEM models based on the full Tripartite Influence Model were also evaluated. A resulting model was found to be an adequate fit to the data, supporting the viability of the Tripartite Model as a useful framework for understanding processes that may predispose young women to develop body image disturbances and eating dysfunction.     

The influence of writing practice on letter recognition in preschool children: a comparison between handwriting and typing

A large body of data supports the view that movement plays a crucial role in letter representation and suggests that handwriting contributes to the visual recognition of letters. If so, changing the motor conditions while children are learning to write by using a method based on typing instead of handwriting should affect their subsequent letter recognition performances. In order to test this hypothesis, we trained two groups of 38 children (aged 3-5 years) to copy letters of the alphabet either by hand or by typing them. After three weeks of learning, we ran two recognition tests, one week apart, to compare the letter recognition performances of the two groups. The results showed that in the older children, the handwriting training gave rise to a better letter recognition than the typing training.