Multisensory integration in multiple reference frames in the posterior parietal cortex

Spatial information processing takes place in different brain regions that receive converging inputs from several sensory modalities. Because of our own movements—for example, changes in eye position, head rotations, and so forth—unimodal sensory representations move continuously relative to one another. It is generally assumed that for multisensory integration to be an orderly process, it should take place between stimuli at congruent spatial locations. In the monkey posterior parietal cortex, the ventral intraparietal (VIP) area is specialized for the analysis of movement information using visual, somatosensory, vestibular, and auditory signals. Focusing on the visual and tactile modalities, we found that in area VIP, like in the superior colliculus, multisensory signals interact at the single neuron level, suggesting that this area participates in multisensory integration. Curiously, VIP does not use a single, invariant coordinate system to encode locations within and across sensory modalities. Visual stimuli can be encoded with respect to the eye, the head, or halfway between the two reference frames, whereas tactile stimuli seem to be prevalently encoded relative to the body. Hence, while some multisensory neurons in VIP could encode spatially congruent tactile and visual stimuli independently of current posture, in other neurons this would not be the case. Future work will need to evaluate the implications of these observations for theories of optimal multisensory integration.Edited by: Marie-Hélène Giard and Mark Wallace     

How psychological momentum changes in athletes during a sport competition

ObjectivesThe present research sought to examine changes in psychological momentum (PM) during sport competitions through the lens of a dynamical systems approach.DesignMale regional-level cyclists competed in cycling duels on home trainers.MethodImages of moving avatars of the cyclists were projected on a wall, and were manipulated so that one cyclist was exposed to an ascending performance scenario (i.e., positive momentum) and the other to a descending performance scenario (i.e., negative momentum). Every 3 min, the cyclists answered PM items by using a keyboard that was placed on the handlebars of their bicycles. Additionally, exerted power was continuously recorded.ResultsResults revealed an asymmetrical critical boundary pattern for PM perceptions indicating that negative PM was triggered more easily than positive PM. Exerted power was generally higher during the negative momentum scenario than during the positive momentum scenario. In addition, exerted power slowly decreased over both momentum scenarios, and this decrease was faster at the very beginning of the negative momentum scenario.ConclusionResults indicate that PM perceptions possess the dynamical properties of nonlinearity and history-dependence. Moreover, the finding that exerted power was higher in the negative momentum scenario was interpreted as a resistance behavior that occurs while experiencing negative momentum. The anticipated decreases in both exerted power and PM perceptions in the negative momentum scenario converge to support the notion that negative PM is a stronger attractor than positive PM. The present study confirms that PM is a dynamical phenomenon and offers fruitful avenues for future research.     

Parametric and nonparametric bootstrap methods for meta-analysis

In a meta-analysis, the unknown parameters are often estimated using maximum likelihood, and inferences are based on asymptotic theory. It is assumed that, conditional on study characteristics included in the model, the between-study distribution and the sampling distributions of the effect sizes are normal. In practice, however, samples are finite, and the normality assumption may be violated, possibly resulting in biased estimates and inappropriate standard errors. In this article, we propose two parametric and two nonparametric bootstrap methods that can be used to adjust the results of maximum likelihood estimation in meta-analysis and illustrate them with empirical data. A simulation study, with raw data drawn from normal distributions, reveals that the parametric bootstrap methods and one of the nonparametric methods are generally superior to the ordinary maximum likelihood approach but suffer from a bias/precision tradeoff. We recommend using one of these bootstrap methods, but without applying the bias correction.     

The role of oculomotor information in the learning of sequential aiming movements

With their eyes initially on either the home, midline, or final end position, 30 participants practiced a 2-target aiming movement. After 120 acquisition trials, participants performed a retention test and were then transferred to each of the other 2 eye conditions. During acquisition, all groups improved over practice, but the home group showed the greatest improvement. The temporal improvement was most pronounced in the times spent after peak velocity. Retention and transfer tests indicated that participants performed best under eye-movement conditions that were the same as the 1 they had practiced in. There was also positive transfer of training between conditions in which the oculomotor information was similar. Thus, to optimize learning, one should practice under the same afferent and oculomotor conditions that will be required for the final performance.     

Effect of personality dimensions on the diurnal pattern of motor activity

The effects of personality dimensions, age, and gender on 24-hour motor activity patterns were studied in 101 healthy subjects between 20-70 years. We measured motor activity by wrist-actigraphy and personality dimensions by the Tridimensional Personality Questionnaire (TPQ) of Cloninger. Random Regression Models were used to estimate the effects of personality dimensions, age, and gender on the diurnal pattern of motor activity. Harm Avoidance as well as Reward Dependence influenced the overall level of motor activity, independent of age and gender. Subjects high on Harm Avoidance showed lower activity levels than subjects low on Harm Avoidance, whereas subjects high on Reward Dependence had higher overall levels of motor activity than subjects low on Reward Dependence. Older subjects were found to be less active than younger subjects, but the activity level did not differ between males and females.     

Friendship and transcendence

International Journal for Philosophy of Religion -     

Measurements effects in reattribution research

In studies investigating the effects of reattribution training, reattributing to effort is confounded with forcing subjects to think about causes of their performance. An experiment was conducted to investigate the effects on performance of having people think about causes of outcomes by means of measuring attributions for success or failure. The results indicate that measurement has a beneficial effect on performance after failure. Measurement of attributions after success does not affect performance or may even slightly deteriorate it. Explanations for these results are discussed.     

The Vajjālaggam: A study in Indian virtue theory

The paper is meant to be a contribution to the study of Indian and comparative ethics. It treats the Vajjālaggam, an anthology of Prākrit stanzas (subhāsita literature) dealing with a variety of topics. Focusing on the ‘ethical’ sections of the VL, it tries to describe and analyse its underlying ethical system. In Part I the different ethical themes of the VL (Valour and Destiny, Virtues and Vices, Masters and Servants, Friendship and Affection, Poverty and Charity) are described in detail. In Part II it is shown that the VL. offers a clear example of a virtue ethic with a strong emphasis on self‐regarding virtues (gunas), based on a pluralistic and instrumental theory of the good. The paper also treats the crucial ethical problem of the relationship between personal well‐being and virtuousness as described in the VL.     

Exposure and response prevention in the natural environment: A comparison with obsessive-compulsive patients

Thirteen obsessive-compulsive clients were treated with different methods of response prevention. Four experimental conditions were obtained through a 2 × 2 factorial design, in which the two main variables were varied: (1) gradual treatment vs flooding; and (2) modeling vs no-modeling. Clients were treated at their homes, three times weekly. Each session lasted 2 hr. Results at the post-test revealed, that modeling was superior to no-modeling (p < 0.05) on avoidance-other compulsions, therapist-rating only. On anxiety-main compulsions, clients rating the gradual method of treatment had been superior to flooding (p < 0.05). No other significant differences were found.     

What is the diplopia threshold?

The magnitude and nature of the diplopia threshold, that is, the value of the retinal disparity at which binocular single vision ends, were studied in four experiments. The results show that the magnitude of the diplopia threshold is highly dependent on the subject tested (differences up to a factor of 6), the amount of training the subject has received (differences up to a factor of 2.5), the criterion used for diplopia (limits for unequivocal singleness of vision were up to a factor of 3 lower than those for unequivocal doubleness of vision), and the conspicuousness of disparity that can be influenced both by the surrounding stimuli (differences up to a factor of 3.5) and stereoscopic depth (differences up to a factor of 4.5). Our data do not confirm previous findings of interference effects associated with the initial appearance of binocular disparity when test stimuli are presented tachistoscopically. A remarkable finding was that the magnitude of the diplopia threshold seems to be determined by the amount of intrinsic noise in the disparity domain, as revealed by the standard deviations of the thresholds for tachistoscopically presented test stimuli. The overall results suggest that the diplopia threshold is, in essence, not the rigid boundary of a dead zone, but, rather, a disparity level corresponding to a lenient criterion for singleness of vision which leads touseful interpretation of the percept of the stimulus without disparity, given the variability of this percept due to intrinsic noise in the disparity domain.