The early facilitatory effect of a peripheral spatially noninformative prime stimulus depends on target stimulus features

We investigated the dependency of the early facilitatory effect of a prime stimulus (S1) on the physical characteristics of the target stimulus (S2). A go-no go reaction time paradigm was used. The S1 was a gray ring and the S2s were a white vertical line, a white horizontal line, a white cross and a white small ring, all inside a white ring with the same dimensions as the S1. S1 onset-S2 onset asynchrony was 100 ms. The stimuli appeared randomly in any one of the quadrants of a monitor screen. The S2 could occur at the same position as the S1 or at a different one. We observed a strong facilitatory effect when the vertical line or the horizontal line was the go stimulus and no effect when the cross was the go stimulus. These results show that the features of the target stimulus can be decisive for the appearance of the facilitatory effect of a peripheral spatially noninformative prime stimulus.

Sleep-wake pattern of medical students: early versus late class starting time

The sleep-wake cycle of students is characterized by delayed onset, partial sleep deprivation and poor sleep quality. Like other circadian rhythms, the sleep-wake cycle is influenced by endogenous and environmental factors. The aim of the present study was to determine the effects of different class starting times on the sleep-wake pattern of 27 medical students. The data were collected during two medical school semesters having different class starting times. All subjects answered the Portuguese version of the Horne and Östberg Morningness/Eveningness Questionnaire, the Pittsburgh Sleep Quality Index (PSQI) and kept a sleep diary for two weeks during each semester. Better sleep quality (PSQI = 5.3 vs 3.4), delayed sleep onset (23:59 vs 0:54 h) and longer sleep duration (6 h and 55 min vs 7 h and 25 min) were observed with the late schedule. We also found reduced sleep durations during weekdays and extended sleep durations during weekends. This pattern was more pronounced during the semester with the early class schedule, indicating that the students were more sleep deprived when their classes began earlier in the morning. These results require further investigation regarding the temporal organization of our institutions.