Interleg coordination in quiet standing: influence of age and visual environment on noise and stability

The authors reexamined reported effects of age, illumination, and stationary visible structure on the net center of pressure (COP) derived from dual, side-by-side force plates (J. Kinsella-Shaw, S. Harrison, C. Colon-Semenza, & M. Turvey, 2006 ) from the perspective of axial postural control. They questioned how left and right COP(x)(t), COP(y)(t), and vertically oriented ground reactive force, GRF(z)(t), coordinated during quiet standing. The Cross-recurrence Quantification (CRQ) revealed that coordination was primarily between fluctuations of similar direction, with coordination of left and right COP(y) (t) (anteroposterior fluctuations) dominant. CRQ also revealed that (a) illumination and structure affected the interlimb dynamics of older (M age = 72.2 ± 4.90 years) participants more than their younger (M age = 22.8 ± 0.83 years) counterparts, and (b) older participants exhibited greater interlimb entrainment (dynamical stability) in the presence of greater interlimb noise.     

Changes in Behaviour and Body Weight Following a Single or Double Social Defeat in Rats

In a series of experiments, the consequences of a single and double social conflict on various behaviours and body weight in rats were studied. Animals were subjected to social defeat by placing them into the territory of an aggressive male conspecific for one hour, either once, or twice at the same time on two consecutive days. To assess the consequences of social defeat, three experiments were performed with independent groups of rats. In the first experiment, an open field test was performed two days after the last conflict. Locomotor activity was strongly reduced after social defeat. There were no differences between the single and double defeat group. To assess the effects of social defeat on subsequent social behaviour, a second experiment was performed in which experimental animals were confronted with an unfamiliar non-aggressive rat two days after a single or double conflict. Social defeat resulted in a reduction of social contact with the unfamiliar conspecific. There was no difference between the single and double conflict group. In the third experiment, the effects of social conflict on food intake, body weight and saccharine preference were measured. Food intake was not affected after a single conflict, but in the double conflict group food intake was decreased for several days. Body weight gain was decreased after both single and double social defeat. The decrease was stronger in the double conflict group. Water intake and saccharine preference were not significantly affected. This study revealed that social defeat in rats causes pronounced changes in various behaviours and body weight. Different aspects of behaviour are differentially affected by defeat with respect to the magnitude and time course of the changes induced. Moreover, different behavioural parameters are differentially sensitive to repetition of the stressor.     

Comparison of dynamic (effortful) touch by hand and foot

Spatial perception by dynamic touch is a well-documented capability of the hand and arm. Morphological and physiological characteristics of the foot and leg suggest that such a capability may not generalize to that putatively less dexterous limb. The authors examined length perception by dynamic touch in a task in which weighted aluminum rods were grasped by the hand and wielded about the wrist or secured to the foot and wielded about the ankle. Participants' (N = 10) upper and lower extremities were comparable in terms of (a) the accuracy and consistency of length perception and (b) their sensitivity to manipulations of the moments of the mass distribution of the rods. The authors discuss those results in terms of the field-like structure of the haptic perceptual system, an organization that may underlie what appears to be functional, rather than anatomical, specificity.     

Effects of visual environment on quiet standing by young and old adults

The authors manipulated the circumstances in which individuals are typically embedded when standing upright by manipulating the intensity of light and the stationary structure of the environment. They expected that the manipulations would affect 12 older participants (aged 65-82 years) more than it would 12 younger participants (aged 22-24 years). Linear (e.g., total path length) and nonlinear (e.g., maximum line length of recurrent points in phase space) measures of the center of pressure time series confirmed that expectation. Moreover, for some measures, there was a suggestion that participants' visual contrast sensitivity (an index of neurophysiological age) was a more important contributing factor overall than was their chronological age. In the Discussion, the authors highlight the significance of interactive effects of environmental, organismic, and task constraints on quiet standing.     

Psychological skills and mindfulness training effects on the psychological wellbeing of undergraduate music students: An exploratory study

This study explored the efficacy of psychological skills and mindfulness training intervention on the psychological wellbeing of undergraduate music students. Participants were undergraduate music students (n = 36) from the Department of Music at a South African university, 21 of whom were elected to take the psychological skills and mindfulness training intervention. Data on their self-reported psychological wellbeing, psychological skills, mindfulness and performance anxiety levels were collected pre-and post-intervention. The analysis applied non-parametric procedures to determine changes in students’ psychological wellbeing after the seven-week intervention programme. Findings suggest improvements in psychological wellbeing, psychological skills, mindfulness and performance anxiety with training. Psychological skills and mindfulness training may have benefits to the psychological wellbeing of music students.