Characteristics of Unintentional Movements by a Multijoint Effector

The authors explored the phenomenon of unintentional changes in the equilibrium state of a multijoint effector produced by transient changes in the external force. The subjects performed a position-holding task against a constant force produced by a robot and were instructed not to intervene voluntarily with movements produced by changes in the robot force. The robot produced a smooth force increase leading to a hand movement, followed by a dwell time. Then, the force dropped to its initial value leading to hand movement toward the initial position, but the hand stopped short of the initial position. The undershoot magnitude increased linearly with the peak hand displacement and exponentially with dwell time (time constant of about 1 s). For long dwell times, the hand stopped at about half the total distance to the initial position. The authors interpret the results as consequences of a drift of the referent hand coordinate. Our results provide support for back-coupling between the referent and actual body configurations during multijoint actions and produce the first quantitative analysis of this phenomenon. This mechanism can also explain the phenomena of slacking and force drop after turning visual feedback off during accurate force production task.     

Categorization by movement direction: Retrieval-induced forgetting of motor sequences grouped by motion features

We investigated the organized storage of motor sequences in memory by assuming that processes related to interference at retrieval are indicative of memory organization. Effects resulting from these processes, thus, would allow inferences on how motor sequences are represented and organized. Participants learned motor sequences that were categorized by the direction of the initial movement. The subsequent selective retrieval of a subset of sequences of one category resulted in retrieval-induced forgetting (RIF) for the non-retrieved sequences of the same category. RIF occurred in an explicit recall test (Experiment 1), as well in an implicit test assessing memory with novel cues (Experiment 2). The results suggest that RIF affected motor programmes and that other cues as the used effectors (here movement direction) can be used for the organization of procedural memory. Basic retrieval dynamics apparently operate within the declarative and procedural systems in a similar way.     

The analyst and analysand as citizens in the world

Beginning with Jung's reflections on individuation as a starting point, this article examines the analytic relationship in the context of our current reality. The latter exerts pressures of all sorts that do not favour individuation. Indeed, geopolitical commentators see present‐day society as marked globally by excessive self‐love that seeks to dominate, at the expense of the other. Given that such forms of dominance are now also very prevalent in the workplace, this article examines how to help the increasing number of individuals with highly successful professional careers who suffer from this pressure and who then seek analysis. ‘Progressive movement’, an indicator of and incentive to change, is examined by studying the narrative processes emerging from dream activity ‐ including dreaming with the hands in the sand tray ‐ in the co‐transference. The article highlights how ‘progressive movement’, founded on narrative Competence and on the reflective function, may generate experiences of ‘realistic hope’. The latter signals the start of an individuation process in the analytic couple and, simultaneously, the transformation of both the analyst and the analysand into good enough ‘citizens in the world’.     

Laying Claim to Martin Luther King Jr. and the Civil Rights Legacy

This essay assesses the oft-made link between Walter Rauschenbusch and Martin Luther King Jr. Denying neither Rauschenbusch’s influence on King nor King’s social gospel status, it nevertheless questions the way historians locate Rauschenbusch’s legacy in King and the civil rights movement. This strategy, however unintentionally, reproduces the white social gospel’s “astigmatism” on race and undermines the contributions of black social gospel (and other neglected) leaders even as revised histories affirm them. After exploring King’s references to Rauschenbusch and Rauschenbusch’s reflections on race, the paper compares their theologies. This comparison reveals key differences on race and economic justice that ramify across Rauschenbusch’s and King’s distinctive articulations of social gospel categories, further complicating historians’ claims on King. Oversimplifying the connection between these important figures in religious ethics distorts theological understanding of social gospel legacies and compromises their power for future generations.     

Revisiting preschoolers' living things concept: a microgenetic analysis of conceptual change in basic biology

Many preschoolers know that plants and animals share basic biological properties, but this knowledge does not usually lead them to conclude that plants, like animals, are living things. To resolve this seeming paradox, we hypothesized that preschoolers largely base their judgments of life status on a biological property, capacity for teleological action, but that few preschoolers realize that plants possess this capacity. To test the hypothesis, we taught 5-year-olds one of four biological facts and examined the children's subsequent categorization of life status for numerous animals, plants, and artifacts. As predicted, a large majority of 5-year-olds who learned that both plants and animals, but not artifacts, move in goal-directed ways inferred that both plants and animals, but not artifacts, are alive. These children were considerably more likely to draw this inference than peers who learned that the same plants and animals grow or need water and almost as likely to do so as children who were explicitly told that animals and plants are living things and that artifacts are not. Results also indicated that not all biological properties are extended from familiar animals to plants; some biological properties are first attributed to plants and then extended to animals.     

An experimentally confirmed statistical model on arm movement

The purpose of this research work was to develop a methodology to model arm movement in normal subjects and neurologically impaired individuals through the application of a statistical modelling method. Thirteen subjects with Parkinson's disease and 29 normal controls were recruited to participate in an arm motor task. An infrared optoelectronic kinematic movement analysis system was employed to record arm movement at 50 times per second. This study identified the modified extended Freundlich model as one that could be used to describe this task. Results showed that this model fit the data well and that it has a good correspondence between the observed and the predicted data. However, verification of the model showed that the residuals contained a sizeable autocorrelation factor. The Cochrane and Orcutt method was applied to remove this factor, which improved the fit of the model. Results showed that Parkinson's disease subjects had a higher autocorrelation coefficient than the normal subjects for this task. A positive correlation (r(s) = 0.72, p < 0.001) was found between the Langton-Hewer stage and the autocorrelation coefficient of PD subjects. This finding suggests that if autocorrelation is positively correlated with disease progression, clinicians in their clinical practice might use the autocorrelation value as a useful indicator to quantify the progression of a subjects' disease. Significant differences in model parameters were seen between normal and Parkinson's disease subjects. The use of such a model to represent and quantify movement patterns provides an important base for future study.     

Parallel processing across neural systems: implications for a multiple memory system hypothesis

A common conceptualization of the organization of memory systems in brain is that different types of memory are mediated by distinct neural systems. Strong support for this view comes from studies that show double (or triple) dissociations between spatial, response, and emotional memories following selective lesions of hippocampus, striatum, and the amygdala. Here, we examine the extent to which hippocampal and striatal neural activity patterns support the multiple memory systems view. A comparison is made between hippocampal and striatal neural correlates with behavior during asymptotic performance of spatial and response maze tasks. Location- (or place), movement, and reward-specific firing patterns were found in both structures regardless of the task demands. Many, but not all, place fields of hippocampal and striatal neurons were similarly affected by changes in the visual and reward context regardless of the cognitive demands. Also, many, but not all, hippocampal and striatal movement-sensitive neurons showed significant changes in their behavioral correlates after a change in visual context, irrespective of cognitive strategy. Similar partial reorganization was observed following manipulations of the reward condition for cells recorded from both structures, again regardless of task. Assuming that representations that persist across context changes reflect learned information, we make the following conclusions. First, the consistent pattern of partial reorganization supports a view that the analysis of spatial, response, and reinforcement information is accomplished via an error-driven, or match-mismatch, algorithm across neural systems. Second, task-relevant processing occurs continuously within hippocampus and striatum regardless of the cognitive demands of the task. Third, given the high degree of parallel processing across allegedly different memory systems, we propose that different neural systems may effectively compete for control of a behavioral expression system. The strength of the influence of any one neural system on behavioral output is likely modulated by factors such as motivation, experience, or hormone status.     

中文阅读及发展性阅读障碍眼动研究新进展

中文阅读眼动特征的评估参数主要包括注视点停留位置、眼跳、回视和注视时间等。基于眼动技术,并结合生理技术,研究者已揭示出正常读者中文阅读的多方面特点和规律。但对发展性阅读障碍的眼动研究,国内还没有开展起来。从上述两个角度出发,这里总结了正常读者中文阅读的眼动研究,并探讨了发展性阅读障碍者的眼动特征及机制。     

Verb movement in acquisition and aphasia: same problem, different solutions-evidence from Dutch

This paper focuses on verb movement in agrammatism and child language. We present data from a sentence completion experiment with 6 Dutch agrammatic aphasics and 21 Dutch-speaking children. The experiment compares completion of matrix clauses (which require verb movement) and embedded clauses (where such movement is not required) in these two populations. The results reveal a clear asymmetry: Both agrammatics and children do very well with embedded clauses but fail in 50% with the matrix clauses. It is concluded that the problem which both populations are facing is one of verb movement rather than verb inflection. An error analysis of the responses reveals that, although both agrammatics and children try to avoid movement, they apply different strategies to achieve this goal.