Pupil Size Is Sensitive to Low-Level Stimulus Features, Independent of Arousal-Related Modulation.

Similar to a camera aperture, pupil size adjusts to the surrounding luminance. Unlike a camera, pupil size is additionally modulated both by stimulus properties and by cognitive processes, including attention and arousal, though the interdependence of these factors is unclear. We hypothesized that different stimulus properties interact to jointly modulate pupil size while remaining independent from the impact of arousal. We measured pupil responses from human observers to equiluminant stimuli during a demanding rapid serial visual presentation (RSVP) task at fixation and tested how response amplitude depends on contrast, spatial frequency, and reward level. We found that under constant luminance, unattended stimuli evoke responses that are separable from changes caused by general arousal or attention. We further uncovered a double-dissociation between task-related responses and stimulus-evoked responses, suggesting that different sources of pupil size modulation are independent of one another. Our results shed light on neural pathways underlying pupillary response.

Enhanced neuronal activity by suffruticosol A extracted from Paeonia lactiflora via partly BDNF signaling in scopolamine-induced memory-impaired mice.

Neurodegenerative diseases are explained by progressive defects of cognitive function and memory. These defects of cognition and memory dysfunction can be induced by the loss of brain-derived neurotrophic factors (BDNF) signaling. Paeonia lactiflora is a traditionally used medicinal herb in Asian countries and some beneficial effects have been reported, including anti-oxidative, anti-inflammatory, anti-cancer activity, and potential neuroprotective effects recently. In this study, we found that suffruticosol A is a major compound in seeds of Paeonia lactiflora. When treated in a SH-SY5 cell line for measuring cell viability and cell survival, suffruticosol A increased cell viability (at 20 µM) and recovered scopolamine-induced neurodegenerative characteristics in the cells. To further confirm its neural amelioration effects in the animals, suffruticosol A (4 or 15 ng, twice a week) was administered into the third ventricle beside the brain of C57BL/6 mice for one month then the scopolamine was intraperitoneally injected into these mice to induce impairments of cognition and memory before conducting behavioral experiments. Central administration of suffruticosol A into the brain restored the memory and cognition behaviors in mice that received the scopolamine. Consistently, the central treatments of suffruticosol A showed rescued cholinergic deficits and BDNF signaling in the hippocampus of mice. Finally, we measured the long-term potentiation (LTP) in the hippocampal CA3-CA1 synapse to figure out the restoration of the synaptic mechanism of learning and memory. Bath application of suffruticosol A (40 µM) improved LTP impairment induced by scopolamine in hippocampal slices. In conclusion, the central administration of suffruticosol A ameliorated neuronal effects partly through elevated BDNF signaling.

North Korean refugee doctors' preliminary examination scores.

PURPOSE: Although there have been studies emphasizing the re-education of North Korean (NK) doctors for post-unification of the Korean Peninsula, study on the content and scope of such re-education has yet to be conducted. Researchers intended to set the content and scope of re-education by a comparative analysis for the scores of the preliminary examination, which is comparable to the Korean Medical Licensing Examination (KMLE). METHODS: The scores of the first and second preliminary exams were analyzed by subject using the Wilcoxon signed rank test. The passing status of the group of NK doctors for KMLE in recent 3 years were investigated. The multiple-choice-question (MCQ) items of which difficulty indexes of NK doctors were lower than those of South Korean (SK) medical students by two times of the standard deviation of the scores of SK medical students were selected to investigate the relevant reasons. RESULTS: The average scores of nearly all subjects were improved in the second exam compared with the first exam. The passing rate of the group of NK doctors was 75%. The number of MCQ items of which difficulty indexes of NK doctors were lower than those of SK medical students was 51 (6.38%). NK doctors' lack of understandings for Diagnostic Techniques and Procedures, Therapeutics, Prenatal Care, and Managed Care Programs was suggested as the possible reason. CONCLUSION: The education of integrated courses focusing on Diagnostic Techniques and Procedures and Therapeutics, and apprenticeship-style training for clinical practice of core subjects are needed. Special lectures on the Preventive Medicine are likely to be required also.