Sequential Aiming with Two Limbs and the One-Target Advantage

Movement times to the first target in a 2-target sequence are typically slower than in 1-target aiming tasks. The 1-target movement time advantage has been shown to emerge regardless of hand preference, the hand used, the amount of practice, and the availability of visual feedback. The authors tested central and peripheral explanations of the 1-target advantage, as postulated by the movement integration hypothesis, by asking participants to perform single-target movements, 2-target movements with 1 limb, and 2-target movements in which they switched limbs at the first target. Reaction time and movement time data showed a 1-target advantage that was similar for both 1- and 2-limb sequential aiming movements. This outcome demonstrates that the processes underlying the increase in movement time to the 1st target in 2-target sequences are not specific to the limb, suggesting that the 1-target advantage originates at a central rather than a peripheral level.     

The Effects of Force and Direction Uncertainty on Choice Reaction Time in an Isometric Force Production Task

The two experiments reported examined the temporal organization of force and direction motor-programming processes in a step-input tracking type task. Both experiments observed a reduction in reaction time in the direction-uncertain conditions compared to the direction-certain ones. Thus it seems as though the direction decision does not have to precede the selection of the proper amount of force. Experiment 2 observed an underadditive interaction between levels of direction uncertainty (certain or uncertain) and levels of force uncertainty (certain or uncertain). This interaction was interpreted as support for a parallel organization of the processes responsible for the programming of force and direction and thus, strongly supports the parallel model of programming recently proposed by Klapp (1977a, b).     

A Cerebral Hyperventilation Index for Electroencephalography

This study was an attempt to determine the effect of drive on probability learning. Each of two groups of Ss was divided into high- and low-drive groups on the basis of MAS scores. Each S was given 200 trials on a probability learning task, with 70 per cent reinforcement on one side and 30 per cent reinforcement on the other. At the .05 level, there was no difference between groups in probability choices, and neither group differed from the objective probability scores. The results are discussed in terms of the number of trials involved, the introduction of emotional arousal, and Hullian theory. On the basis of a comparison with the results of previous studies, it was suggested that investigators be cautious in generalizing probability learning results from one species to another.     

A Natural Approach in Mental Health Practice: Occupational Adaptation Revealed

A single case study of the stories told by one occupational therapist about her clients in mental health settings is presented in this article. Qualitative analysis revealed key concepts of the role of the occupational therapist as defined by occupational adaptation theory, along with unique perspectives of occupational therapy in mental health settings. The outcome of this study is a demonstration of the unique insight occupational therapy brings to addressing client recovery in mental health settings, specifically from an occupational adaptation perspective. This insight should enlighten others as to the necessity of skilled occupational therapy in mental health settings.     

Inter-individual variability of forces and modular muscle coordination in cycling: A study on untrained subjects

The aim of this study was to investigate the muscle coordination underlying pedaling in untrained subjects by using the muscle synergies paradigm, and to connect it with the inter-individual variability of EMG patterns and applied forces. Nine subjects performed a pedaling exercise on a cycle-simulator. Applied forces were recorded by means of instrumented pedals able to measure two force components. EMG signals were recorded from eight muscles of the dominant leg, and Nonnegative Matrix Factorization was applied to extract muscle synergy vectors W and time-varying activation coefficients H. Inter-individual variability was assessed for EMG patterns, force profiles, and H. Four modules were sufficient to reconstruct the muscle activation repertoire for all the subjects (variance accounted for >90% for each muscle). These modules were found to be highly similar between subjects in terms of W (mean r = .89), while most of the variability in force profiles and EMG patterns was reflected, in the muscle synergy structure, in the variability of H. These four modules have a functional interpretation when related to force distribution along the pedaling cycle, and the structure of W is shared with that present in human walking, suggesting the existence of a modular motor control in humans.     

Sensory substitution: an approach to the experimental study of perception / Sustitución sensorial: un abordaje para el estudio experimental de la percepción

Abstract

Sensory substitution refers to the phenomenon where object and environment information normally acquired through one sense can be obtained by another sense. For example, visual input being provided by hearing or touching. Sensory substitution devices are technological designs that transform the characteristics of one sensory modality into stimuli of another sensory modality. These devices were developed with two purposes: (1) to assist people with sensory disabilities in daily tasks; and (2) to study the involved mechanisms of brain plasticity. This article reviews studies in which sensory substitution phenomenon is employed as a methodological strategy to study visual perception. Furthermore, its use is discussed as an experimental platform to contrast new perceptual theories and underlying neurophysiological mechanisms that are currently under review.     

The Soul Cluster: Reconsideration of a Millennia Old Concept

The article presents a comparative analysis of the theories on conceptions of soul in indigenous and early European traditions. The focal point of the study is the observation that the concept of soul is noticeably complex in aboriginal cultures, and its plural—especially tripartite—nature is the rule rather than the exception. Another observation is that the described pluralism, the number of soul components, and their attributes go through speculative changes as the tradition moves away of tribal origins, which have the shamanic state of consciousness as experiential source of knowledge instead of scholarly theorization. A three-network model of human experience is drawn to support the tripartition cum trilocation concept of soul.     

Identity in the asphalt jungle

We present a study of 40 youngsters who live and work in the streets of Mexico City and who have abandoned their homes for significant periods of time. They seek out their own means of survival from a very young age. In many cases they have children of their own already as teenagers. The Seminario de Sociopsicoanálisis was invited to take part in a project aimed at facilitating the access of these children to graphic arts, artistic creation and therapeutic listening. This article presents our principal findings of the children's everyday life conditions, their work and their dreams, based on data obtained from social character questionnaires – with which therapeutic intervention in this project began. Vignettes of two case studies are also presented. The interviews were complemented by data gathered in weekly sessions attended by the youngsters on a voluntary bases. The sessions attested to both the narcissistic, aggressive impulsiveness of these youngsters and the vital effort they make toward their own recovery and toward establishing affective emotional ties with instructors and therapists. We found that socio‐psychoanalytic methods could be used successfully to expand the scope of psychoanalytic theoretic postulates about character to a non‐clinical, disadvantaged population. By analyzing the content of the psychoanalytically guided interviews we were able to recognize the central, distinctive motive, which leads these youngsters to run away from home and forge their own sense of identity.     

EDITORIAL

The aim of the present study was to evaluate the usefulness of Barkley’s (1997a) model of inhibition and executive functioning in describing the deficits associated with Attention Deficit Hyperactivity Disorder (ADHD). Besides group differences, the present study addressed the question of independent effects of inhibition and the other executive functions in discriminating between children with ADHD and controls and how well, in terms of sensitivity and specificity, these measures can classify the children into the correct group. The results showed that children with ADHD differed significantly from controls with regard to measures of inhibition as well as all other executive function measures, except repetition of hand movements. In logistic regression models, three different measures tapping inhibition, working memory and emotion regulation were shown to be significant independent predictors of group membership. The sensitivity for these three variables as a set was 76.2, the specificity was 90.5, with a total of 86% of the sample correctly classified. When excluding the parental rating of emotion regulation, the overall classification rate decreased some, but was still relatively high in comparison with previous studies within this area of research.     

Editorial

With the aim of increasing knowledge about processes of change in psychodynamic individual child psychotherapy, sessions that could be called turning points were analysed.