Effect of environmental exposure to a maternally-learned odorant on anxiety-like behaviors at weaning in mice

Animal Cognition - Early sensory experience, such as exposure to maternal or other environmental factors, is considered to influence neurocognitive development and behaviors. In many species,...     

Investigation of boron-enriched Cottrell atmospheres in FeAl on an atomic scale by three-dimensional atom-probe field-ion microscopy

In 1949, on the basis of theoretical considerations, Cottrell proposed the concept of 'atmospheres' (called later by his name) to explain some specific behaviour of materials during plastic deformation, such as sharp yield-point formation or the Portevin-LeChatelier effect. In this letter, atomic-scale observations and three-dimensional analyses of a Cottrell atmosphere are reported. They have been performed by three-dimensional atom-probe field-ion microscopy techniques. The ability of this new experimental method to provide atomic-resolution images, both structural and chemical, was confirmed; the basic stacking structure of (001) planes in FeAl could be visualized with success. Moreover the presence of a <001> edge dislocation was also detected in the analysed zone. Further, B enrichment was measured in the vicinity of this defect; the B-rich region appeared as a pipe 5 nm in diameter, parallel to the dislocation line. The concentration of B in the core reached 3 at.%; this local enrichment in boron was accompanied by an Al depletion of more than 10 at.%. Boron in FeAl has a well known tendency to segregate to internal interfaces. In this letter, we show experimental evidence of the solute segregation to dislocation lines. The observed effects of this segregation on mechanical properties of FeAl, both at room temperature and high temperatures, are also discussed.     

Effect of Analogy Instructions with an Internal Focus on Learning a Complex Motor Skill

This study examined the effects of an analogy in learning breaststroke swimming. Two groups of participants had 20 lessons on how to increase their stroke length. The participants in the experimental condition received an analogy with an internal focus of attention. Inter-limb coordination showed qualitative changes in this group: a greater increase in swimming efficiency (i.e., a coordination closer to anti-phase [?50° before learning and ?125° after] and a 10% decrease in the time spent in-phase). The findings showed that an internal focus of attention induced by analogy could be beneficial in improving the quality of inter-limb swimming coordination.     

Regularization and a general linear model for event-related potential estimation

The usual event-related potential (ERP) estimation is the average across epochs time-locked on stimuli of interest. These stimuli are repeated several times to improve the signal-to-noise ratio (SNR) and only one evoked potential is estimated inside the temporal window of interest. Consequently, the average estimation does not take into account other neural responses within the same epoch that are due to short inter stimuli intervals. These adjacent neural responses may overlap and distort the evoked potential of interest. This overlapping process is a significant issue for the eye fixation-related potential (EFRP) technique in which the epochs are time-locked on the ocular fixations. The inter fixation intervals are not experimentally controlled and can be shorter than the neural response’s latency. To begin, the Tikhonov regularization, applied to the classical average estimation, was introduced to improve the SNR for a given number of trials. The generalized cross validation was chosen to obtain the optimal value of the ridge parameter. Then, to deal with the issue of overlapping, the general linear model (GLM), was used to extract all neural responses inside an epoch. Finally, the regularization was also applied to it. The models (the classical average and the GLM with and without regularization) were compared on both simulated data and real datasets from a visual scene exploration in co-registration with an eye-tracker, and from a P300 Speller experiment. The regularization was found to improve the estimation by average for a given number of trials. The GLM was more robust and efficient, its efficiency actually reinforced by the regularization.