The role of mask coherence in motion-induced blindness

Motion-induced blindness (MIB) is the perceived disappearance of a salient target when surrounded by a moving mask. Much research has focused on the role of target characteristics on perceived disappearance by a coherently moving mask. However, we asked a different question: mainly, are there certain characteristics about the mask that can impact disappearance? To address this, we behaviorally tested whether MIB is enhanced or reduced by the property of common fate. In experiments 1, 2, and 3, we systematically manipulated the motion coherence of the mask and measured the amount of target disappearance. Results showed that, as mask coherence increased, perceived target disappearance decreased. This pattern was unaffected by the lifetime of the moving dots, the dot density of the motion stimulus, or the target eccentricity. In experiment 4, we investigated whether the number of motion directions contained in an incoherent mask could account for our findings. Using masks containing 1, 3, and 5 motion directions, we found that disappearance did not increase proportionally to the number of motion directions. We discuss our findings in line with current proposed mechanisms of MIB.     

Do different types of US produce similar evaluative conditioning? An examination with contingency-awareness and cognitive load

Evaluative conditioning (EC) refers to a modulation in the liking of a neutral stimulus after it has been paired with an unconditioned stimulus (US). Previous studies have uncovered some of the mechanisms responsible for EC, but many parameters remain unknown. The study addresses two questions: Is the amplitude of EC and the impact of cognitive variables are the same for different types of US? We compared three types of US: shocks, single images and multiple semantically related images. This conditioning occurred while participants maintained a concurrent cognitive load, or not. Our results indicate that all types of US produced a significant EC of similar amplitude. Furthermore, the two cognitive variables had a similar impact across all types of US. Specifically, contingency-awareness was related to the amplitude of EC, particularly in the cognitive load group. Our results illustrate the importance of within study comparisons to assess different parameters on EC.     

DEPLOYMENT STATUS: A DIRECT OR INDIRECT EFFECT ON MOTHER–CHILD ATTACHMENT WITHIN A CANADIAN MILITARY CONTEXT?

Research has suggested that military spouses experience increased depressive symptoms and parenting stress during a military member's deployment. A relationship between maternal depressive symptoms, parenting stress, and child attachment security has been found in the general population, as has an indication that social support may provide a buffering effect. While there appears to be an association between the emotional well‐being of military spouses and child emotional well‐being during deployment, data are limited regarding the association between maternal emotional well‐being and child attachment security. The current study explores the association between deployment status and child attachment to the nonmilitary parent (i.e., the mother in this study) in a sample of 68 Canadian military families. Results revealed a significant impact of deployment status on maternal depressive symptoms and on quality of child attachment. The impact of deployment status on attachment was not mediated through the maternal variables, and despite a main effect of social support on the maternal variables, there was no moderating effect. Thus, our results suggest that deployment may affect child attachment independently of maternal well‐being.     

Saccadic eye movements: what do they tell us about aging cognition?

Although the relationship between age-related cognitive decline and saccadic eye movement (SEM) deficits has been outlined, specific cognitive alterations underlying age-related changes in saccadic performance remain unclear. This study attempted to better understand the nature of aging effects on SEMs. We compared SEMs in younger and older adults in prosaccade (PS) and antisaccade (AS) tasks under gap, step, and overlap conditions. We also examined relationships between these performances and several neuropsychological scores. Twenty-eight younger adults (YA), 24 older adults under 65 years (OA_<65) and 24 over 65 years (OA_>65) of age completed a neuropsychological evaluation, PS and AS tasks. Our results showed that latencies, AS cost, time to correct AS errors, and uncorrected AS, increased with aging. YA showed higher overlap effects than OA_>65 and OA_<65. Importantly, correlations and regressions revealed close relationships not only between latencies and processing speed measures but also between the AS cost and the inhibition process measures. Correct saccades and the time to correct AS errors were closely related to the inhibition process and cognitive flexibility measures. These findings suggest that the progressive age-related decline of processing speed and executive attention are associated with, and can be highlighted though SEMs in PS and AS tasks.     

A dynamical framework to understand performance trade-offs and interference in dual tasks.

This study demonstrated that the dynamic pattern approach may reconcile resource and outcome conflict theories to explain performance in dual tasks. Participants performed a bimanual coordination task and a reaction time task with different conditions of attentional priority. Results showed a trade-off between pattern variability and reaction time when priority was given to the coordination task. Such a trade-off was indicative of resource allocation. An analysis of perturbation in the bimanual coordination revealed interference, a reputed sign of outcome conflict. Moreover, interference diminished substantially when priority was given to the bimanual task. The coexistence of performance trade-off and outcome conflict suggests that these two phenomena are not mutually exclusive. Rather, both may follow from modifying the coupling between the limbs through attention.     

Effect of gaze orientation on tactilo-kinesthetic performance

Twenty-two normal right-handed subjects indicated with their index finger the midpoint of a horizontal rod that they could not see. Subjects performed this task while directing their gaze either centrally or toward four different locations (5 degrees or 30 degrees to the left or to the right of the midline). Results showed an overall leftward bias in rod bisection, which increased when subjects used their right hand and fixated a right-sided visual target. Thus, orienting of gaze can affect a nonvisual, tactilo-kinesthetic spatial task. The possible mechanisms of this interaction are discussed with respect to activation-orienting theories egocentric hypotheses and directional trends.     

The Yin and Yang of cell cycle progression and differentiation in the oligodendroglial lineage

In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor cells involves errors in the sequence of events that normally occur during development when progenitors proliferate, migrate through the white matter, contact the axon, and differentiate into myelin-forming oligodendrocytes. Multiple mechanisms underlie the eventual progressive deterioration that typifies the natural history of developmental demyelination in LD and PVL and of adult-onset demyelination in MS. Over the past few years, pathophysiological studies have mostly focused on seeking abnormalities that impede oligodendroglial maturation at the level of migration, myelination, and survival. In contrast, there has been a strikingly lower interest for early proliferative and differentiation events that are likely to be equally critical for white matter development and myelin repair. This review highlights the Yin and Yang principles of interactions between intrinsic factors that coordinately regulate progenitor cell division and the onset of differentiation, i.e. the initial steps of oligodendrocyte lineage progression that are obviously crucial in health and diseases.