Assessment of student performance in problem-based learning tutorial sessions.

OBJECTIVES: To assess student performance during tutorial sessions in problem-based learning (PBL). DESIGN: A 24-item rating scale was developed to assess student performance during tutorial sessions in problem-based learning (PBL) as conducted during the pre-clinical years of Medical School at the National Autonomous University of Mexico. Items were divided into three categories: Independent study, Group interaction and Reasoning skills. Fourteen tutors assessed 152 first and second-year students in 16 tutorial groups. An exploratory factor analysis with an Oblimin rotation was carried out to identify the underlying dimensions of the questionnaire. SETTING: Medical School at the National Autonomous University of Mexico. SUBJECTS: Medical students. RESULTS: Factor analysis yielded four factors (Independent study, Group interaction, Reasoning skills, and Active participation) which together accounted for 76.6% of the variance. Their Cronbach reliability coefficients were 0.95, 0.83, 0.94 and 0. 93, respectively, and 0.96 for the scale as a whole. CONCLUSIONS: It was concluded that the questionnaire provides a reliable identification of the fundamental components of the PBL method as observable in tutorial groups and could be a useful assessment instrument for tutors wishing to monitor students' progress in each of these components.

Electroencephalographic analysis of the sleep-inducing actions of cholecystokinin.

Cortical EEG analysis of the effects of cholecystokinin (CCK) on sleep were performed in rats treated intraperitoneally with 1,10, or 20 micrograms/kg CCK8. Latency to the first episode of non-REM sleep was significantly reduced from 29 minutes to 16 minutes. No change in total waking time, total non-REM sleep, or total REM sleep was seen at any dose over the first hour after CCK administration. Locomotor activity was significantly reduced by 10 micrograms/kg CCK8 during the first ten minutes only. The temporal separation between the sleep-latency reduction and the behavioral inactivity induced by CCK indicate that these effects are distinguishable phenomena. Sleep does not appear to be a primary cause for the satiety-related behavioral effects of CCK.

The role of central and peripheral cholecystokinin in mediating appetitive behaviors.

Cholecystokinin (CCK) reduces total food consumption in mice, rats, pigs, sheep, monkeys and humans. Behaviors associated with an underlying state of satiety are reported after CCK administration. Reductions in exploration and social interactions by CCK are not due to true sedation or sleep, as measured by cortical EEG recordings. The satiety effects appear to be mediated by peripheral CCK receptors, through a feedback loop involving the vagus nerve. The conceptual link between the behavioral functions of CCK as a putative satiety signal and its established digestive functions are discussed.

The effects of various protein synthesis inhibitors on the sleep-wake cycle of rats.

The present investigation sought to determine the effects of Anisomycin (A), Chloramphenicol (ChA), Vincristine (V), and Penicilline G on the sleep-wake cycle of rats. It was found that both high and low doses of anisomycin decreased rapid eye movement (REM) sleep, while only high doses of ChA and V produced such a decrease. Slow wave sleep (SWS) was unaffected by these drugs. Penicilline G, on the other hand, had no effect on the sleep-wake cycle. It was further shown that the reduction of REM sleep was the result of a decrease in the number of REM periods rather than in the duration of each individual period. These results suggest that protein synthesis may participate in the mechanisms that trigger REM sleep.

Paradoxical sleep in two species of avian predator (Falconiformes).

Periods of disconjugate. and conjugate eye movements occur during the sleep cycle in Buteo jamaicensis arborealis and Herpetotheres cachinnans chapmanni. Electromyograms are essentially isoelectric throughout sleep. Slow waves appear only in short bursts of low amplitude in contrast to the long trains of high-amplitude waves reported for chickens and pigeons.