The effect of attending to motor overflow on its voluntary inhibition in young and older adults

Motor overflow refers to involuntary movement or muscle activity coinciding with voluntary movement. We examined whether 16 young adults (18-30 years) and 16 older adults (50-80 years) could voluntarily inhibit overflow. Participants performed a finger pressing task, exerting 50% of their maximal force. Overflow was concurrently recorded in the non-task hand. In the first condition, participants were not made aware of their motor overflow. Then participants, though informed of it, were asked to ignore their overflow. Finally, participants were requested to inhibit overflow with, and then without visual feedback, or vice versa. Overflow was exacerbated when older adults were unaware of it, and was reduced once they were informed. For young adults there was no significant difference between these conditions. Both Age Groups could significantly reduce overflow when so requested, independent of visual feedback. Thus motor overflow can be modulated by higher order cognitive control with directed attention.     

Increased saccadic rate during smooth pursuit eye movements in patients at Ultra High Risk for developing a psychosis

Abnormalities in eye tracking are consistently observed in schizophrenia patients and their relatives and have been proposed as an endophenotype of the disease. The aim of this study was to investigate the performance of patients at Ultra High Risk (UHR) for developing psychosis on a task of smooth pursuit eye movement (SPEM). Forty-six UHR patients and twenty-eight age and education matched controls were assessed with a task of SPEM and psychiatric questionnaires. Our results showed that both the corrective and non-corrective saccadic rates during pursuit were higher in the UHR group. There were however no differences in smooth pursuit gain between the two groups. The saccadic rate was related to positive UHR symptoms. Our findings indicate that abnormalities in SPEM are already present in UHR patients, prior to a first psychotic episode. These abnormalities occur only in the saccadic system.     

Capturing lightness between contours

Homogeneously coloured bars may exhibit lightness differences at the intersections. A well-known example is the Hermann grid illusion, where crossing white bars on a black background show dark patches at the crossings. Jung (1973, Handbook of Sensory Physiology volume VII/3, pp 1-152) found that the dark patches persist when thin outlines are drawn at the intersections, and are even visible in foveal vision. Recently, it has been shown that making distortions to the contours of a Hermann grid-like configuration results in the disappearance of the illusory dark spots (Geier et al, 2008 Perception 37 651 665). We show that thin outlines at the crossings of the distorted Hermann grid induce lightness differences in the same direction as in the original Hermann grid illusion, even in foveal vision and in displays consisting of two crossing bars. Our experiments reveal that the induced lightness differences are independent of the luminance polarity and shape of the contours at the intersection. We suggest that the effect results from lateral inhibition and an additional spreading and capturing of these differences between luminance contours. A similar capturing between collinear contours may play a role in peripheral vision in the original Hermann grid.     

Vestibular stimulation affects optic-flow sensitivity

Typically, multiple cues can be used to generate a particular percept. Our area of interest is the extent to which humans are able to synergistically combine cues that are generated when moving through an environment. For example, movement through the environment leads to both visual (optic-flow) and vestibular stimulation, and studies have shown that non-human primates are able to combine these cues to generate a more accurate perception of heading than can be obtained with either cue in isolation. Here we investigate whether humans show a similar ability to synergistically combine optic-flow and vestibular cues. This was achieved by determining the sensitivity to optic-flow stimuli while physically moving the observer, and hence producing a vestibular signal, that was either consistent with the optic-flow signal, eg a radially expanding pattern coupled with forward motion, or inconsistent with it, eg a radially expanding pattern with backward motion. Results indicate that humans are more sensitive to motion-in-depth optic-flow stimuli when they are combined with complementary vestibular signals than when they are combined with conflicting vestibular signals. These results indicate that in humans, like in nonhuman primates, there is perceptual integration of visual and vestibular signals.     

Impaired emotion recognition in music in Parkinson’s disease

Music has the potential to evoke strong emotions and plays a significant role in the lives of many people. Music might therefore be an ideal medium to assess emotion recognition. We investigated emotion recognition in music in 20 patients with idiopathic Parkinson’s disease (PD) and 20 matched healthy volunteers. The role of cognitive dysfunction and other disease characteristics in emotion recognition was also evaluated.     

Financial problems and psychological distress: Investigating reciprocal effects among business owners

Building on conservation of resources theory and the dynamic equilibrium model, this three‐wave longitudinal study among 260 Dutch agricultural business owners (1‐year time intervals) investigated reciprocal relationships between the financial situation of the business and psychological distress. Results of structural equation modelling analyses revealed a negative spiral of farm decline, in which psychological variables played a key role. Experiencing financial problems predicted psychological distress, and acted as a self‐fulfilling prophecy by strengthening intentions to quit the business, which predicted a deterioration of the objective financial situation of the business 1 year later. Moreover, farmers experiencing more psychological distress were more likely to get caught in this negative spiral than business owners with better mental health, because they experienced more financial problems, irrespective of their objective financial situation. Long‐term psychological distress rather than temporary fluctuations in distress levels accounted for this effect.     

How leaders stimulate employee learning: A leader–member exchange approach

This study investigated how leader–member exchange (LMX), goal setting, and feedback are related to employee engagement in learning activities. Two different mechanisms were proposed: a mediating mechanism holding that LMX elicits specific leader behaviours (i.e., goal setting and feedback) which would mediate the LMX‐learning relationship, and a moderating mechanism, holding that LMX would strengthen the effect of these leader behaviours. A sample of 1,112 employees from 7 organizations completed questionnaires that measured LMX, goal specificity, feedback, and self‐reports of employee engagement in learning activities. The 233 direct leaders of these employees completed questionnaires that measured goal difficulty and leader ratings of employee engagement in learning activities. Multi‐level analysis showed that goal difficulty and goal specificity mediated the relationship between LMX and employee engagement in learning activities, and that LMX moderated the relationship of goal difficulty with employee engagement in learning activities. With these findings, the present study contributes to the literatures on LMX, goal setting, and employee development.     

The differential effect of team members' trust on team performance: The mediation role of team cohesion

This study examines team performance as affected by various trusting relationships: trust between team members and the team's trust in their direct manager and in top management. Data for the study were collected from a survey of 690 professional elite athletes (belonging to 59 different sports clubs) playing in the regular, top professional Spanish leagues. The model was tested at the team level. Findings reveal that team member trust with respect to the different foci has both a direct and indirect effect on team performance, and that team player trust and cohesion play a mediating role. This study illustrates the dynamic relationship within teams, and, as such, trust among teammates mediates the relationship between trust in the coach as well as team cohesion in determining team performance. The implications for managing teams in other contexts are also evaluated.     

In the mood for adaptation: how affect regulates conflict-driven control

Cognitive conflict plays an important role in tuning cognitive control to the situation at hand. On the basis of earlier findings demonstrating emotional modulations of conflict processing, we predicted that affective states may adaptively regulate goal-directed behavior that is driven by conflict. We tested this hypothesis by measuring conflict-driven control adaptations following experimental induction of four different mood states that could be differentiated along the dimensions of arousal and pleasure. After mood states were induced, 91 subjects performed a flanker task, which provided a measure of conflict adaptation. As predicted, pleasure level affected conflict adaptation: Less pleasure was associated with more conflict-driven control. Arousal level did not influence conflict adaptation. This study suggests that affect adaptively regulates cognitive control. Implications for future research and psychopathology are discussed.