Preventing neuronal damage and inflammation in vivo during cortical microelectrode implantation through the use of poloxamer P-188.

OBJECTIVE: The aim of this study was to test the efficacy of Poloxamer P188 to reduce cell death and immune response associated with mechanical trauma to cells during implantation of a chronic recording electrode. APPROACH: Ceramic multi-site recording electrodes were implanted bilaterally into 15 adult male Long-Evans rats. One of each pair was randomly assigned to receive a coating of Poloxamer while the other was treated with saline. The extent of neuron loss, and glial cell recruitment were characterized at 2, 4 and 6 weeks post-implantation by stereologic analysis. MAIN RESULTS: At 2 and 4 weeks post-implantation, Poloxamer-coated implants showed significantly fewer glial cells and more neurons in the peri-electrode space than controls; however, this significance was lost by 6 weeks. SIGNIFICANCE: These findings are the first to suggest that Poloxamer has neuroprotective effects in vivo; however, at a fixed loading dose, these effects are limited to approximately 1 month post-implantation.

Is the contextual interference effect generalizable to computer games?

The benefits of learning multiple tasks under an unstructured practice schedule have been extensively demonstrated in the laboratory. The purpose of the present study was to test contextual interference effects in a nonlaboratory setting using computer games as tasks. Undergraduate kinesiology and sport management majors (N = 19) played a computer game simulating the events of the winter Olympics. Participants were randomly assigned to either a Blocked or Random practice schedule, practicing 36 trials of three events. Delayed retention and transfer tests were performed after a 48-hr. retention interval. The dependent variable was time to complete an event. During transfer, participants in the Random schedule (M = 248 sec.) were significantly faster than Blocked (M = 263 sec.) participants. Results support and extend previous contextual interference findings. Transfer was facilitated for participants who learned the events in a Random practice order. Results are discussed in terms of the influence of task characteristics on learning.

The paradox of the contented working woman in intercollegiate athletics administration.

We investigated the paradox of the contented working woman among middle and first-line intercollegiate athletics administrators. In this paradox, women report lower salaries than men but express comparable job satisfaction. The sample comprised 143 women and 371 men in 106 National Collegiate Athletic Association (NCAA) Division I-A institutions. Job satisfaction was measured with the Job Descriptive Index (Smith, Kendall & Hulin, 1969) and Job in General (Ironson, Smith, Brannick, Gibson & Paul, 1989) scales. Analyses revealed the existence of the paradox: Women were paid significantly less, but were equally satisfied with their jobs. Neither gender was satisfied with promotion opportunities or pay, but both were highly satisfied with their jobs in general--another apparent paradox. The disproportionate number of male respondents raised questions about gender equity in athletics administration.

Appropriate summary KR for learning timing tasks under conditions of high and low contextual interference.

Recall and retrieval processes of timing tasks were investigated in a multitask learning experiment using blocked (BL) and random (RA) practice schedules (Battig 1979). The extent to which summary knowledge of results (KR) interacts with order of presentation of practice tasks was the primary topic under investigation. It has been suggested that summary KR may enhance processing of task-relevant information (Schmidt 1991). The processing benefits of summary KR however may be dependent on the presentation order of practice tasks. Seventy-two females responded to the apparent motion of illuminated lights set at three speeds of 224, 313, and 492 cm/s during 90 acquisition, 30 no-KR retention and 20 transfer trials. Subjects' tasks was to push a ball hinged to a lever to coincide with the arrival of a light at a predetermined intercept point. Retrospective verbal reports were obtained immediately following transfer to ascertain the nature of subjects' processing activities. Error data were analyzed on four dependent variables. The most important finding was that longer summary KR lengths for RA subjects (KR10) were beneficial in acquisition and transfer. In contrast, BL subjects were more consistent in transfer if they received KR after each practice trial. A similar trend (p = 0.15) in retention was found in that BL subjects were more consistent as compared to RA, when they learned the tasks with 100% KR. Given the differential results of summary KR for BL and RA, the importance of considering the order of task presentation when investigating summary KR was supported.

Factors influencing rearfoot kinematics during a rapid lateral braking movement.

Understanding the morphological, movement, and biomechanical characteristics that influence rearfoot motion during lateral movements is necessary for footwear design and for the determination of injury mechanisms. The purpose of this study was to identify factors related to rearfoot kinematics during a lateral braking movement. Seven highly skilled male tennis players performed 24 trials of side shuffle movements at various speeds. A rear view of the right leg performing a braking step onto a force platform was filmed. The neutral-O landing style was most commonly demonstrated. Average movement velocity, foot velocity at touchdown, and body mass were variables demonstrating weak or nonsignificant correlations with the rearfoot parameters. Although structural inversion was correlated significantly with the maximum rearfoot angle and velocity (r = -0.52 and -0.69), the results were affected by movement speed and sample size. The biomechanical characteristics displayed the greatest influence on the various rearfoot kinematic parameters. The magnitude of the significant (P less than 0.0001) correlations generally decreased in the following order: maximum horizontal and vertical force gradients, corresponding times to the maximum gradient values, maximum horizontal and vertical forces, and the corresponding times to maximum forces. In conclusion, the gradient-associated parameters were the most useful biomechanical parameters for predicting changes in rearfoot kinematics.