Short and long-term motor skill learning in an accelerated rotarod training paradigm

Rodent models of motor skill learning include skilled forelimb reaching and acrobatic locomotor paradigms. This study characterizes motor skill learning in the accelerated rotarod task. Thirty Long-Evans rats (300-400 g) were trained on an accelerated rotarod (1cm/s(2)) over eight consecutive sessions (=days, 20 trials each). Improvement in rotarod velocities mastered before falling off the rod was observed within and between sessions (plateau after five sessions). Intrasession improvement was incompletely retained at the beginning of the next day's session. Over several training sessions, intrasession improvement diminished, suggesting a ceiling effect. After 1 week of pause, the rotarod skill was retained. Locomotor exercise in a running wheel for 30 min before the first rotarod session did not affect intrasession improvement. Running-wheel exposure for 6 days did not diminish the rate of rotarod skill learning (steepness of the learning curve) but improved overall performance (upward shift of curve). Video analysis of gait on the rotarod showed that rats developed a motor strategy by modifying their gait patterns during training. The data demonstrate that rotarod improvement is not the result of enhanced general locomotor ability or fitness, which are trained in the running wheel, but requires a change in the motor strategy to master the task. Accelerated rotarod training can be regarded a valid paradigm for motor skill learning over short (intrasession, minutes) and long time frames (intersession, days).     

Predictive pointing movements and saccades toward a moving target

The authors investigated whether and, if so, how velocity information is used to control predictive manual pointing movements and saccades. Participants (N = 6) intercepted an occluded moving target as if it were still visible. They kept their eyes fixated while the target moved. The target traveled over a fixed distance and changed its velocity on the way. The presentation time of the final velocity was varied. Both the eye and the hand overshot the slow target and undershot the fast target, particularly when the duration of the final velocity was short. Thus, responses were biased in the direction of the target's initial velocity. The error seemed to arise because participants did not take their latency into account when aiming at the target. Instead, they strategically aimed farther ahead when the target was fast. Amplitude was also more related to the position of velocity change than to final velocity duration. Both findings suggest that target velocity is not extrapolated but that individuals add an increment to the position of velocity change.     

It's not my fault: when and why attributions to prejudice protect self-esteem

This study tested the hypothesis that awareness of the possibility of being a target of discrimination can provide individuals with a means of self-esteem protection when they are faced with negative outcomes. Men and women contemplated being rejected from a course due to sexism, personal deservingness, or an exclusively external cause. Regardless of gender, participants in the sexism condition blamed themselves less, attributed the rejection less to internal causes, and anticipated feeling less depressed than those in the personal deservingness condition. Furthermore, the more participants discounted the rejection--blamed it more on discrimination than themselves--the less depressed emotions they anticipated feeling. Discounting did not buffer participants from feeling hostility or anxiety. These findings advance our understanding of when and why attributions to prejudice protect emotional well-being.     

The Werther effect and assisted suicide

In the course of a large epidemiological study in the region of Basle, Switzerland, from 1992 to 1996, a considerable rise in suicides assisted by the right-to-die society EXIT was uncovered after wide press coverage of an assisted double suicide of a prominent couple in that region in March 1995. Further investigation revealed that the rise of assisted suicides for a period of 2 years after the critical event was statistically significant compared to the 2 years previous to the double suicide. This was especially true for women older than 65 years. Hence, the almost enthusiastic kind of reporting about this event was apt to induce imitation suicides or a "Werther-effect."     

Semantic categorization in the human brain: spatiotemporal dynamics revealed by magnetoencephalography

We examined the cortical representation of semantic categorization using magnetic source imaging in a task that revealed both dissociations among superordinate categories and associations among different base-level concepts within these categories. Around 200 ms after stimulus onset, the spatiotemporal correlation of brain activity elicited by base-level concepts was greater within than across superordinate categories in the right temporal lobe. Unsupervised clustering of data showed similar categorization between 210 and 450 ms mainly in the left hemisphere. This pattern suggests that well-defined semantic categories are represented in spatially distinct, macroscopically separable neural networks, independent of physical stimulus properties. In contrast, a broader, task-required categorization (natural/man-made) was not evident in our data. The perceptual dynamics of the categorization process is initially evident in the extrastriate areas of the right hemisphere; this activation is followed by higher-level activity along the ventral processing stream, implicating primarily the left temporal lobe.     

The psychological effects of Hurricane Andrew on ethnic minority and Caucasian children and adolescents: a case study

The impact of Hurricane Andrew on 212 African American, Caucasian, and Hispanic elementary and middle school children was examined at 6 months postdisaster. Using self-report instruments, this case study examined the predictive utility of several hypothesized mediators of children's reactions to disaster. Results showed higher levels of intrusive symptomatology for girls and for elementary school children as compared with their middle school counterparts. No differences were found with reference to race. The lack of findings concerning race is addressed, as well as implications for future studies.     

Potenzen und Grenzen einer allgemeinen Psychotherapietheorie

Ohne Zusammenfassung     

A Uniform Approach for Characterizing the Provably Total Number-Theoretic Functions of KPM and (Some of) its Subsystems

In this article we show how to extract with the use of the Buchholz-Cichon-Weiermann approach to subrecursive hierarchies from Rathjen's 1991 ordinal analysis of KPM a characterization of the provably total number-theoretic functions of KPM and some of its (most prominent) subsystems in a uniform and direct way.     

Between- and within-person level motivational precursors associated with career exploration

Career exploration is a critical process for child and adolescent development leading people toward suitable work and developing a vocational identity. The present study examined the role of motivational precursors, namely work valences and personal agency beliefs, in explaining in-breadth and in-depth career exploration. Given the dynamic nature of motivation, we teased apart the between-person differences and within-person variabilities in motivational precursors to examine how they are independently associated with career exploration. Two hundred one high school students comprised the sample and were surveyed three consecutive years. Results revealed that work valences and agency beliefs were associated with career exploration at both the between- and within-person level. Further, when individuals exhibited greater level of agency beliefs and positive valences, they were more likely to exhibit more in-depth exploration one year later. Implications for career guidance are discussed.