The role of the primary motor cortex during skill acquisition on a two-degrees-of-freedom movement task

One can partially eliminate motor skills acquired through practice in the hours immediately following practice by applying repetitive transcranial stimulation (rTMS) over the primary motor cortex. The disruption of acquired levels of performance has been demonstrated on tasks that are ballistic in nature. The authors investigated whether motor recall on a discrete aiming task is degraded following a disruption of the primary motor cortex induced via rTMS. Participants (N = 16) maintained acquired performance levels and patterns of muscle activity following the application of rTMS, despite a reduction in corticospinal excitability. Disruption of the primary motor cortex during a consolidation period did not influence the retention of acquired skill in this type of discrete visuomotor task.     

A simple and unified approach to human voluntary movements

In his provocative article, F. Mechsner (2004) advances the thesis that human voluntary movements are subject to "psychological" or "perceptual-cognitive" control and are thus organized "without regard to efferent patterns" (p. 355). Rather than considering in detail the experiments that he proffered by way of support, the present author discusses the degree to which that supposition has appeal on the grounds of simplicity and is defined in terms that are compatible with a unified science.     

Interaction of directional,neuromuscular and egocentric constraints on the stability of preferred bimanual coordination patterns

We investigated how the relative direction of limb movements in external space (iso- and non-isodirectionality), muscular constraints (the relative timing of homologous muscle activation) and the egocentric frame of reference (moving simultaneously toward/away the longitudinal axis of the body) contribute to the stability of coordinated movements. In the first experiment, we attempted to determine the respective stability of isodirectional and non-isodirectional movements in between-persons coordination. In a second experiment, we determined the effect of the relative direction in external space, and of muscular constraints, on pattern stability during a within-person bimanual coordination task. In the third experiment we dissociated the effects on pattern stability of the muscular constraints, relative direction and egocentric frame of reference. The results showed that (1) simultaneous activation of homologous muscles resulted in more stable performance than simultaneous activation of non-homologous muscles during within-subject coordination, and that (2) isodirectional movements were more stable than non-isodirectional movements during between-persons coordination, confirming the role of the relative direction of the moving limbs in the stability of bimanual coordination. Moreover, the egocentric constraint was to some extent found distinguishable from the effect of the relative direction of the moving limbs in external space, and from the effect of the relative timing of muscle activation. In summary, the present study showed that relative direction of the moving limbs in external space and muscular constraints may interact either to stabilize or destabilize coordination patterns.     

Loving, discernment, and distance: pastoral care in schizophrenia

Schizophrenia is very common in our society, yet many people, both clergy and lay, are afraid of it and do not know what to do when confronted with someone who suffers from the disorder. Strange ideas and behavior can be frightening for those who don't understand and often result in further marginalization, even within the church community. This article seeks to outline the main features of schizophrenia and considers how to deal with particular situations which may arise in pastoral care. It suggests ways of dealing with people who express religious delusions and also argues that the "staples" of pastoral care--relationship building, empathy and inclusion--may not always be appropriate in the care of people with schizophrenia, who often need a "safe distance" between themselves and others. Some practical advice for families is also offered.     

The control and learning of patterns of interlimb coordination: past and present issues in normal and disordered control

The present paper provides a historical note on the evolution of the behavioral study of interlimb coordination and the reasons for its success as a field of investigation in the past decades. Whereas the original foundations for this field of science were laid down back in the seventies, it has steadily grown in the past decades and has attracted the attention of various scientific disciplines. A diversity of topics is currently being addressed and this is also expressed in the present contributions to the special issue. The main theme is centered on the brain basis of interlimb coordination. On the one hand, this pertains to the study of the control and learning of patterns of interlimb coordination in clinical groups. On the other hand, basic neural approaches are being merged together with behavioral approaches to reveal the neural basis of interlimb coordination.     

General Strain Theory and the Relationship Between Early Victimization and Drug Use

This study uses general strain theory to examine the direct and indirect relationship between early victimization and drug use. Few previous studies measure strain as victimization. Also, past studies tend to combine drug use measures with delinquency measures. This study expands this research by operationalizing strain as early victimization and using measures of both frequency and onset of drug use. National Survey of Adolescents data is used to test the hypotheses. The results show that when youth are victimized they will use drugs more frequently and use drugs at a younger age. These relationships were only partially mediated by social bonds and negative emotions.