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).     

The Force/Force-Variability Relationship Under Controlled Temporal Conditions

Previously, an inverted U relationship between force and force variability was demonstrated in both static and dynamic responses. Recent research suggests that the inverted U function may be due to a lack of control of the temporal aspects of the response. To investigate this hypothesis, we examined the relationship between force and force variability in rapid movements under controlled temporal conditions. Subjects (N = 4) made rapid reversal responses with a horizontal lever (using elbow flexion and extension) such that the time to reversal (160 ms) and the distance to reversal (45°) were held constant in each of six load conditions (either 0, .260, .520, .780,1.040, or 1.560 kg added to the lever). When time to reversal and time to peak acceleration were held constant, a curvilinear relationship between force and force variability resulted, suggesting that the inverted U function is related to control of the temporal aspects of the response.     

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.     

Deep structure,cognition and rebirth: Propositions for viability and vitality in human systems

This paper describes systems dynamics related to deep structure and development processes in human systems, to the process of arresting entropy or premature death in these systems and to the relationship between the cognition of deep structure, its outward manifestation and human systems viability and vitality. The paper proposes that inherent forces are present in systems that act to bring about alignment between inner deep structure and a system's manifested outer structures and processes, thereby enhancing viability and vitality. Deep structure is seen as a force toward self‐organization and rebirth.     

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.