Peripheral Constraint Versus On-line Programming in Rapid Aimed Sequestial Movements

The purpose of this investigation was to examine how the programming and control of a rapid aiming sequence shifts with increased complexity. One objective was to determine if a preprogramming/peripheral constraint explanation is adequate to characterize control of an increasingly complex rapid aiming sequence, and if not, at what point on-line programming better accounts for the data. A second objective was to examine when on-line programming occurs. Three experiments were conducted in which complexity was manipulated by increasing the number of targets from 1 to 11. Initiation- and execution-timing patterns, probe reaction time, and movement kinematics were measured. Results supported the peripheral constraint/pre-programming explanation for sequences up to 7 targets if they were executed in a blocked fashion. For sequences executed in a random fashion (one length followed by a different length), preprogramming did not increase with complexity, and on-line programming occurred without time cost. Across all sequences there was evidence that the later targets created a peripheral constraint on movements to previous targets. We suggest that programming is influenced by two factors: the overall spatial trajectory, which is consistent with Sidaway’s subtended angle hypothesis (1991), and average velocity, with the latter established based on the number of targets in the sequence. As the number of targets increases, average velocity decreases, which controls variability of error in the extent of each movement segment. Overall the data support a continuous model of processing, one in which programming and execution co-occur, and can do so without time cost

Force modulation as a source of hand differences in rapid finger tapping

The purpose of this study was to examine the factors contributing to hand differences in rapid single finger tapping. To this end, task-defined temporal variables and motor outflow, as reflected by the magnitude and duration of force, were simultaneously measured. Thirty-one right-handed college age subjects performed a rapid finger-tapping task with the index finger of the right and left hands. The order of hand use was counterbalanced across subjects. Significant differences favoring the right hand were found in the rate of tapping as indicated by the inter-tap interval, dwell (duration of key closure), the interval between force peaks and the variance of the force peak intervals. Additionally, relative to the left hand, the right hand used significantly smaller amounts of force and exhibited less variation in force. These data are conceptually consistent with Kimura's (1979) contention that the left hemisphere is uniquely specialized to control sequences of action such as postural transitions. However, Kimura argues that this unique ability is manifest in multiple-finger sequences but not rapid single finger tapping. The present data indicate such a mechanism may be observed in rapid single finger tapping if the appropriate dependent measures are obtained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26681/1/0000228.pd

Motor Learning Processes In A Movement-Scaling Task In Olivopontocerebellar Atrophy And Parkinson's Disease

Nine Parkinson's disease (PD), seven olivopontocerebellar atrophy (OPCA) patients and two age-matched control groups learned a linear arm movement-scaling task over 2 days, requiring movements proportional in length to visually presented target-bars. Scaling was acquired through knowledge of results (KR concerning the direction and magnitude of errors) following every second acquisition trial. Initial acquisition of both groups was significantly worse than their respective controls (poorer movement scaling), but rapidly improved to nearly identical levels. Retention for the PD group's movement scaling was as good as controls initially, but markedly poorer after 24 h. The OPCA group did not show this deficit. Both patient groups extrapolated accurately to longer, previously unpracticed target distances (no KR provided), suggesting an unimpaired capacity to generate and use an internal representation of the movement scaling. They also rapidly learned a new scaling relationship when the gain was changed. Overall, the learning of this movement-scaling task was not adversely affected in OPCA, and the impairment was restricted primarily to longer-term retention in PD. The study suggests that: (1) the ability to acquire movement scaling in a task that requires conscious use of error feedback and no new coordination may depend little on the cerebellum, and (2) the basal ganglia may participate in longer-term storage of scaling information

Programming of sequential rapid aiming movements.

Distribution of motor programming before and during execution of a rapid aimed sequence was studied to develop a model that best describes such movements. Using a simple reaction time paradigm, a series of targets were contacted as rapidly as possible, maintaining a 90% rate of accuracy. Complexity of the movement was manipulated by increasing the number of targets in the sequence from one to seven, and/or by including a unique element--either a target smaller than all others, or a triple hit on one target, i.e., contacting one target three times before proceeding to the next. The additional programming necessary to execute the more complex sequences was measured using initiation- and execution-timing patterns and movement kinematics. Experiment one indicated that on-line programming occurred for seven-target sequences in which there was a unique element. Also, the type of unique element affected how programming was distributed. Whereas programming for a small target occurred early in the sequence regardless of its position, indicating that the overall program was affected, programming for the triple hit occurred one or two segments before its execution, indicating that a local parameter was re-specified. One result from experiment two indicated that the spatial constraint perpendicular to the line of movement created by the last target of the sequence (up to seven targets, total distance of 35 cm, subtended angle of 4.9\sp\circ) influenced the programming and execution of the movement. The tighter the constraint, the longer the time spent preprogramming. This finding is consistent with Sidaway's (1991) subtended angle hypothesis. Secondly, the greater the distance of the last target from the beginning of the sequence, the longer the execution times from target to target. One exception was if a triple hit occurred late in the sequence. This result indicated that a triple hit partitioned programming of the sequence; only movements up to the triple hit were preprogrammed. A model is proposed in which programming before initiation (and early in execution, if necessary) occurs as a function of the degree to which variability in both extent and direction of the movement must be controlled.Ph.D.Kinesiology and PsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103495/1/9319633.pdfDescription of 9319633.pdf : Restricted to UM users only

Practice Effects in Three-Dimensional Sequential Rapid Aiming in Parkinson's Disease

One hypothesized role of the basal ganglia, based largely on findings in Parkinson's disease (PD) patients, is the control of movement sequences. We examined changes in performance with practice of a movement sequence in PD patients and age-matched controls (n = 8 per group). Subjects practiced a complex three-dimensional sequential aiming task over 2 days, completing 180 trials, with the goal to minimize response time within specified accuracy limits. The results indicated that both groups became faster in planning the movement, and both groups moved more quickly through the sequence with practice. The PD group's decrease in movement time occurred primarily within the first 45 trials, whereas the control group continued to improve through the first 150 trials. Flight time (time between targets) to a small target decreased with practice in both groups, but flight time to a large target decreased only in the control group. This finding indicates that error corrective processes are more amenable to practice than ballistic processes in people with PD. There was little evidence that either group improved their performance by planning shorter (lower) trajectories, but rather increased mean velocity. Contact time (time on target) decreased with practice in both groups, and there were no group differences. These data indicate that practice can improve performance, both in planning and in specific execution processes

More than one road leads to Rome: A narrative review and meta-analysis of physical activity intervention effects on cognition in youth

A growing body of research indicates that physical activity (PA) positively impacts cognitive function in youth. However, not all forms of PA benefit cognition equally. The purpose of this review was to determine the effect of different types of chronic PA interventions on cognition in children and adolescents. A systematic search of electronic databases and examination of the reference lists of relevant studies resulted in the identification of 28 studies. Seven categories of PA were identified, based on all possible combinations of three types of PA (aerobic, motor skill, cognitively engaging), and four comparison groups (no treatment, academic, traditional physical education, aerobic). Effect sizes were calculated based on means and SDs at the post-test using Hedge's g formula, which includes a correction for small sample bias. Each study was only entered once in each intervention-comparator category. Full data were provided from 21 studies (28 effect sizes; n=2042 intervention; n=2002 comparison group). Overall, chronic PA interventions had a significant small-to-moderate effect on cognition (0.46). Moderate significant positive effects were identified when PA interventions were compared to no treatment (0.86) or academic content (0.57). A non-significant effect was noted when PA interventions were compared to traditional physical education (0.09) or aerobic group (0.80). However, high heterogeneity in pooled effect sizes suggests that important differences in the qualitative characteristics of the PA intervention and comparison interventions may exist. Effect sizes based on comparisons between different types of PA interventions and comparison groups are discussed in order to identify possible directions for future investigations. We conclude that chronic PA interventions have a positive impact on cognitive function in youth, but more systematic research is needed in this area

Measuring the Effectiveness of Team-Based Learning Outcomes in a Human Factors Course

This paper will describe a synopsis of the development and application of a survey instrument to assess team skills and professional development outcomes of Team-Based Learning (TBL) in a human factors course. TBL is an advancing teaching pedagogy that shifts instruction from a traditional lecture-based teaching paradigm to a structured learning sequence that includes individual student preparation outside of class followed by active, in-class problem solving exercises completed by student learning teams. As an evolving teaching method, TBL appears to be producing new empirical learning outcomes in areas that have only preliminarily been explored. Traditionally, the effectiveness of TBL has been assessed through grades and numeric measures of performance; however, TBL was designed to both enhance learning as well as team collaboration and critical thinking skills. Thus there a need for a validated measurement instrument emerged to assess the development of team skills in TBL classes. The newly developed survey instrument is designed to assess three overarching factors within the TBL framework: 1) attitudes and beliefs about learning; 2) motivation to learn; and 3) professional development. A pilot survey was created and administered in the summer of 2013 to 25 undergraduate students at a large Mid-Western university and was tested for internal consistency. To further improve the quality of the survey, two focus groups were also conducted. In the fall of 2013 the revised survey was administered to 182 undergraduate students and in the spring of 2014 to 197 undergraduate students. Based on encouraging results, the survey was used to assess the learning outcome gains in a graduate level human factors course. Preliminary results for this sample showed modest gains in critical thinking and external motivation. The survey has the potential to provide instructors a mechanism to measure student learning gains in TBL educational settings.Copyright Human Factors and Ergonomics Society 2015. Posted with permission.</p