Error Feedback Frequency Affects Automaticity But Not Accuracy and Consistency After Extensive Motor Skill Practice

Earlier studies addressed the effects of feedback frequency on movement accuracy and consistency. The authors additionally addressed the effects on motor automatization. High error feedback frequencies may induce attentional control processes and impede motor automatization. In a pre-post design, 42 participants were assigned to 2 groups with different feedback frequencies and practiced an arm movement sequence with 760 trials in 5 sessions. The 100% group practiced with feedback on 3 movement reversals of the sequence after each trial. The 14% group practiced with 14% frequency according to a fading schedule. Only the 14% group showed a decrease in dual-task costs indicating an increase in automaticity. Group differences in movement accuracy and consistency were not evident.     

高血压患者应激反应特点及行为人格的关系研究

为了解高血压患者心血管反应的特征及与健康人群的差异,使用实验和问卷调查的方法对高血压患者和健康居民进行研究。结果显示,两组在任务期和恢复期的心血管反应差异显著（P〈0．05）;病例组的健康实践行为和消极应对方式水平较高,积极应对方式有待提升;健康实践行为和恢复期舒张压呈负相关,积极应对方式和任务期收缩压呈正相关（P〈0...     

Differential effects of cue specificity and list length on the prospective and retrospective prospective-memory components

Event-based prospective memory (PM) refers to the ability to remember to perform an intended action at an appropriate moment that is indicated by some cue. It has been shown that increasing the number of PM cues as well as decreasing the cues' specificity can impair PM performance. Although both manipulations result in similar detrimental effects to PM accuracy, they may affect different underlying cognitive processes. To test this hypothesis, we manipulated both the number of cues and cue specificity and found the expected detrimental effects on PM accuracy. Analyses with the multinomial model of PM, which considers false PM responses and accounts for guessing biases, imply that the cue-list-length manipulation affected cue singularisation as well as intention retrieval, whereas cue specificity selectively affected intention retrieval. These results are original evidence that the performance decrements from the two manipulations have different cognitive underpinnings.     

The supplementary motor area in motor and perceptual time processing: fMRI studies

The neural bases of timing mechanisms in the second-to-minute range are currently investigated using multidisciplinary approaches. This paper documents the involvement of the supplementary motor area (SMA) in the encoding of target durations by reporting convergent fMRI data from motor and perceptual timing tasks. Event-related fMRI was used in two temporal procedures, involving (1) the production of an accurate interval as compared to an accurate force, and (2) a dual-task of time and colour discrimination with parametric manipulation of the level of attention attributed to each parameter. The first study revealed greater activation of the SMA proper in skilful control of time compared to force. The second showed that increasing attentional allocation to time increased activity in a cortico-striatal network including the pre-SMA (in contrast with the occipital cortex for increasing attention to colour). Further, the SMA proper was sensitive to the attentional modulation cued prior to the time processing period. Taken together, these data and related literature suggest that the SMA plays a key role in time processing as part of the striato-cortical pathway previously identified by animal studies, human neuropsychology and neuroimaging.     

Evaluation of two methods of prompting drivers to use specific exits on conflicts between vehicles at the critical exit

The Florida Department of Transportation used a series of changeable-message signs that functioned as freeway guide signs to divert traffic to Universal Theme Park via one of two eastbound exits based on traffic congestion at the first of the two exits. An examination of crashes along the entire route indicated a statistically significant increase in crashes at the first eastbound exit following the actuation of the system. Furthermore, all of the crashes occurred in close proximity to the exit gore (the crosshatched area at exits that drivers are not supposed to enter or traverse) at the first exit. In Experiment 1, behavioral data were collected using an alternating treatments design. These data revealed that reassigning the exit signs was effective in producing a change in the percentage of drivers using each of the two exits. These data also showed that the reassignment of the theme park exit was associated with an increase in the percentage of motor vehicle conflicts that consisted of vehicles cutting across the exit gore. An analysis revealed that the method used for switching the designated or active theme park exit on the series of changeable-message signs led to the presentation of conflicting messages to some motorists, thus resulting in erratic driving behavior (cutting across the exit gore). In Experiment 2, the treatment evaluated the use of a phased method of switching the designated theme park exit to eliminate the delivery of conflicting messages. The new method for switching the designated theme park exit was not associated with an increase in motorists cutting across the exit gore.     

Emotional Responses to APO E Genotype Disclosure for Alzheimer Disease

The purpose of our study is to assess the emotional responses to disclosing APO E genotype to asymptomatic older adults at increased risk for Alzheimer disease (AD). This is a longitudinal cohort study of volunteer subjects who were aged 50 years or over, asymptomatic for (AD), had a family history of AD, passed a psychological assessment, and participated in pre- and post-test genetic counseling and three follow-up visits over 10 months. We analyzed responses by three emotional constructs: depressed, worried, and relieved. Three hundred and twenty-eight subjects were screened, 76 received their APO E genotype. When emotional responses occurred it was immediate, between baseline and the 1 month follow-up. Emotional reactions did not change significantly past 1 month. Our results suggest that for emotionally stable persons, disclosing results of their APO E genotype, high risk subjects did not report more depression or worry and low risk subjects felt relieved by knowing the results. Future studies should evaluate the risks of disclosure to family members involved in the diagnostic work-up of a relative and include subjects from a broader range of emotional stability and socioeconomic background.     

The Neural Basis of Motor-Skill Learning

Recent work indicates that motor-skill learning is supported by four processes: a strategic process that selects new goals of what to change in the environment, a perceptual-motor integration process that adjusts to new relationships between environmental stimuli and the appropriate motor response, a sequencing process that learns sequences of motor acts, and a dynamic process that learns new patterns of muscle activations. These four processes can operate in one of two modes: an unconscious mode, in which one is aware only of the goal of the movement, or a conscious mode, in which one consciously controls detailed aspects of the movement. This article provides an overview of these four processes and two modes, and describes their neural bases.     

Methylphenidate Does Not Modify the Impact of Response Frequency or Stimulus Sequence on Performance and Event-Related Potentials of Children with Attention Deficit Hyperactivity Disorder

Twenty-six children with attention deficit/hyperactivity disorder (ADHD) participated in a double-blind trial consisting of 2 consecutive weeks each of placebo and methylphenidate (M = 26.92 mg/day = 0.78 mg/kg/day). As expected, stimulant therapy resulted in moderate weight loss, increased somatic complaints, and teacher and parent reports of reduced inattentiveness, aggression, and oppositionality. In both phases of the trial, patients were tested in a choice reaction time task assessing two aspects of the task that presumably affect response selection: response frequency (ratio of targets/nontargets = 25/75 vs. 50/50) and stimulus sequence (alternations vs. repetitions). Both manipulations yielded expected results on performance and event-related potentials (ERPs). Stimulant treatment increased accuracy and speed among younger children and curtailed variability of reaction time for the sample as a whole. However, methylphenidate did not affect ERPs. In combination, the results imply that the enhancement of performance by methylphenidate does not involve the demands of response selection examined in this study.     

A Comparison of Least-to-Most Prompts and Progressive Time Delay on the Disruptive Behavior of Students with Autism

We compared the effects of two instructional strategies on the frequency of errors and episodes of disruptive behavior of 4 students with autism. In Phase I, easy and difficult tasks were presented to determine whether the tasks were associated with differential rates of disruptive behavior. Phase II compared the effects of a least-to-most prompting procedure (LTM) to a progressive time delay procedure (PTD) on errors and disruptive behavior when difficult tasks were presented. Observers sequentially recorded instructor instructions, response prompts, prompts for appropriate sitting, and feedback statements; and student disruptive, correct, error, and no responses during 1:1 sessions. Results showed PTD produced fewer errors than LTM for all 4 students, and lower rates of disruptive behavior for 2 students. When PTD was implemented as the final phase with 2 of the students, rates of disruptive behavior associated with the task previously taught with LTM immediately decreased. Conditional probability statements indicated that disruptive behavior occurred infrequently with all 4 students when effective response prompts were used.