The interplay of attention and bimanual coordination dynamics

Despite their common origin, studies on motor coordination and on attentional load have developed into separate fields of investigation, bringing out findings, methods, and theories which are diverse if not mutually exclusive. Sitting at the intersection of these two fields, this article addresses the issue of behavioral flexibility by investigating how intention modifies the stability of existing patterns of coordination between moving limbs. It addresses the issue, largely ignored until now, of the attentional cost incurred by the central nervous system (CNS) in maintaining a coordination pattern at a given level of stability, in particular under different attentional priority requirements. The experimental paradigm adopted in these studies provides an original mix of a classical measure of attentional load, namely, reaction time, and of a dynamic approach to coordination, most suitable for characterizing the dynamic properties of coordinated behavior and behavioral change. Findings showed that central cost and pattern stability covary, suggesting that bimanual coordination and the attentional activity of the CNS involved in maintaining such a coordination bear on the same underlying dynamics. Such a conclusion provides a strong support to a unified approach to coordination encompassing a conceptualization in terms of information processing and another, more recent framework rooted in self-organization theories and dynamical systems models     

Similarities Between the Psychological Profiles of Complex Regional Pain Syndrome and Conversion Disorder Patients

The psychological profile of 17 Complex Regional Pain Syndrome type I (CRPS) and 20 Conversion Disorder (CD) patients were compared, using the Minnesota Multiphasic Personality Inventory (MMPI) and standardized, semistructured psychological interviews. Both groups presented abnormally high somatization scores. Low anxiety scores in both groups indicate that somatization may have served as a defense mechanism to bind anxiety. Depression was apparent in both groups, indicating that psychological distress accompany these syndromes. About one third of the participants in both groups presented comorbid Axis I disorders, mostly depression and PTSD. CRPS patients have traditionally been looked upon as suffering from mainly organic symptoms, whereas CD patients have been labeled as psychiatric patients. These results may indicate the need to reexamine the traditional classifications in respect to disorders that involve body and mind.     

Correlates of Mental Disorders in the Quebec General Population of 6 to 14-Year Olds

Previous epidemiological studies of correlates of child and adolescent mental disorders in the general population have focused more on child/adolescent and socioeconomic/sociodemographic characteristics than on family characteristics. Moreover, there are no generally accepted methods to analyze and interpret correlates. The purpose of the Quebec Child Mental Health Survey in this regard was twofold: (1) to identify correlates of DSM-III-R internalizing and externalizing disorders according to informant (youth, parent, teacher), for three age groups (6–8, 9–11, and 12–14 years), including relevant family characteristics not considered in previous studies; and (2) to interpret the relative importance of risk indicators by ranking correlates according to strength and consistency of association across age groups. Logistic regression models suggest the inconsistency of correlates across informants. The ranking of correlates reveals that individual and family characteristics make a more important contribution than do socioeconomic characteristics, thereby supporting the relevance of proximal variables in the development of psychopathology.     

Can brown lemurs (<Emphasis Type="Italic">Eulemur fulvus</Emphasis>) learn to deceive a human competitor?

In the present study we asked whether lemurs could learn to manipulate information in order to deceive a human competitive trainer. Four brown lemurs were trained to communicate about the location of a hidden reward to a cooperative trainer, who rewarded the subject if he indicated the baited bowl. Next, a competitive trainer was introduced who kept the reward for himself if the subject indicated the baited bowl. In a first experiment, sessions were randomly assigned to be with either the cooperative or competitive trainer. No subject was able to show an efficient tactic with both trainers. In a second experiment, the participation of the two trainers was randomized across the trials for each session. When trials were mixed, one subject significantly chose baited location when interacting with the cooperative trainer, and reliably increased his choices of the unbaited location when presented with the competitive trainer. As with most other primate species tested under the same paradigm, associative learning may explain deceptive pointing by lemurs in this study.     

Basic visual perceptual processes in children with typical development and cerebral palsy: The processing of surface,length, orientation,and position

The present study aims to assess how the processing of basic visual perceptual (VP) components (length, surface, orientation, and position) develops in typically developing (TD) children (n = 215, 4–14 years old) and adults (n = 20, 20–25 years old), and in children with cerebral palsy (CP) (n = 86, 5–14 years old) using the first four subtests of the Battery for the Evaluation of Visual Perceptual and Spatial processing in children. Experiment 1 showed that these four basic VP processes follow distinct developmental trajectories in typical development. Experiment 2 revealed that children with CP present global and persistent deficits for the processing of basic VP components when compared with TD children matched on chronological age and nonverbal reasoning abilities.     

Plane of motion mediates the coalition of constraints in rhythmic bimanual coordination

The authors hypothesized that the modulation of coordinative stability and accuracy caused by the coalition of egocentric (neuromuscular) and allocentric (directional) constraints varies depending on the plane of motion in which coordination patterns are performed. Participants (N = 7) produced rhythmic bimanual movements of the hands in the sagittal plane (i.e., up-and-down oscillations resulting from flexion-extension of their wrists). The timing of activation of muscle groups, direction of movements, visual feedback, and across-trial movement frequency were manipulated. Results showed that both the egocentric and the allocentric constraints modulated pattern stability and accuracy. However, the allocentric constraint played a dominant role over the egocentric. The removal of vision only slightly destabilized movements, regardless of the effects of directional and (neuro)muscular constraints. The results of the present study hint at considering the plane in which coordination is performed as a mediator of the coalition of egocentric and allocentric constraints that modulates coordinative stability of rhythmic bimanual coordination.