Ethnicity, sleep, mood, and illumination in postmenopausal women

BACKGROUND: This study examined how ethnic differences in sleep and depression were related to environmental illumination and circadian rhythms. METHODS: In an ancillary study to the Women's Health Initiative, 459 postmenopausal women were recorded for one week in their homes, using wrist monitors. Sleep and illumination experience were estimated. Depression was self-rated with a brief adjective check list. Affective diagnoses were made using the SCID interview. Sleep disordered breathing was monitored with home pulse oximetry. RESULTS: Hispanic and African-American women slept less than European-American women, according to both objective recordings and their own sleep logs. Non-European-American women had more blood oxygen desaturations during sleep, which accounted for 26% of sleep duration variance associated with ethnicity. Hispanic women were much more depressed. Hispanic, African-American and Native-American women experienced less daily illumination. Less daily illumination experience was associated with poorer global functioning, longer but more disturbed sleep, and more depression. CONCLUSIONS: Curtailed sleep and poor mood were related to ethnicity. Sleep disordered breathing was a factor in the curtailed sleep of minority women. Less illumination was experienced by non-European-American women, but illumination accounted for little of the contrasts between ethnic groups in sleep and mood. Social factors may be involved

Magnitude, precision, and realism of depth perception in stereoscopic vision

Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing

Learning health professionalism at Makerere University: an exploratory study amongst undergraduate students

<p>Abstract</p> <p>Background</p> <p>Anecdotal evidence shows that unprofessional conduct is becoming a common occurrence amongst health workers in Uganda. The development of appropriate professional values, attitudes and behaviors is a continuum that starts when a student joins a health professional training institution and as such health professionals in training need to be exposed to the essence of professionalism. We sought to explore undergraduate health professions students' perceptions and experiences of learning professionalism as a preliminary step in addressing the problem of unprofessional conduct amongst health workers in Uganda.</p> <p>Methods</p> <p>Eight focus group discussions were conducted with 49 first to fifth year health professions undergraduate students of the 2008/2009 academic year at Makerere University College of Health Sciences. The focus group discussions were recorded and transcribed, and were analyzed using content analysis with emergent coding.</p> <p>Results</p> <p>The difference in the way first and fifth year students of Makerere University College of Health Sciences conceptualized professionalism was suggestive of the decline in attitude that occurs during medical education. The formal curriculum was described as being inadequate while the hidden and informal curricula were found to play a critical role in learning professionalism. Students identified role models as being essential to the development of professionalism and emphasized the need for appropriate role modeling. In our setting, resource constraints present an important, additional challenge to learning universal standards of health professionalism. Furthermore, students described practices that reflect the cultural concept of communalism, which conflicts with the universally accepted standard of individual medical confidentiality. The students questioned the universal applicability of internationally accepted standards of professionalism.</p> <p>Conclusions</p> <p>The findings call for a review of the formal professionalism curriculum at Makerere University College of Health Sciences to make it more comprehensive and to meet the needs expressed by the students. Role models need capacity building in professionalism as health professionals and as educators. In our setting, resource constraints present an additional challenge to learning universal standards of health professionalism. There is need for further research and discourse on education in health professionalism in the Sub-Saharan context of resource constraints and cultural challenges.</p

Sit still and pay attention: Using the Wii Balance-Board to detect lapses in concentration in children during psychophysical testing.

During psychophysical testing, a loss of concentration can cause observers to answer incorrectly, even when the stimulus is clearly perceptible. Such lapses limit the accuracy and speed of many psychophysical measurements. This study evaluates an automated technique for detecting lapses based on body movement (postural instability). Thirty-five children (8-11 years of age) and 34 adults performed a typical psychophysical task (orientation discrimination) while seated on a Wii Fit Balance Board: a gaming device that measures center of pressure (CoP). Incorrect responses on suprathreshold catch trials provided the "reference standard" measure of when lapses in concentration occurred. Children exhibited significantly greater variability in CoP on lapse trials, indicating that postural instability provides a feasible, real-time index of concentration. Limitations and potential applications of this method are discussed

Psychophysics with children: Investigating the effects of attentional lapses on threshold estimates

When assessing the perceptual abilities of children, researchers tend to use psychophysical techniques designed for use with adults. However, children’s poorer attentiveness might bias the threshold estimates obtained by these methods. Here, we obtained speed discrimination threshold estimates in 6- to 7-year-old children in UK Key Stage 1 (KS1), 7- to 9-year-old children in Key Stage 2 (KS2), and adults using three psychophysical procedures: QUEST, a 1-up 2-down Levitt staircase, and Method of Constant Stimuli (MCS). We estimated inattentiveness using responses to “easy” catch trials. As expected, children had higher threshold estimates and made more errors on catch trials than adults. Lower threshold estimates were obtained from psychometric functions fit to the data in the QUEST condition than the MCS and Levitt staircases, and the threshold estimates obtained when fitting a psychometric function to the QUEST data were also lower than when using the QUEST mode. This suggests that threshold estimates cannot be compared directly across methods. Differences between the procedures did not vary significantly with age group. Simulations indicated that inattentiveness biased threshold estimates particularly when threshold estimates were computed as the QUEST mode or the average of staircase reversals. In contrast, thresholds estimated by post-hoc psychometric function fitting were less biased by attentional lapses. Our results suggest that some psychophysical methods are more robust to attentiveness, which has important implications for assessing the perception of children and clinical groups

Visual Performance Fields: Frames of Reference

Performance in most visual discrimination tasks is better along the horizontal than the vertical meridian (Horizontal-Vertical Anisotropy, HVA), and along the lower than the upper vertical meridian (Vertical Meridian Asymmetry, VMA), with intermediate performance at intercardinal locations. As these inhomogeneities are prevalent throughout visual tasks, it is important to understand the perceptual consequences of dissociating spatial reference frames. In all studies of performance fields so far, allocentric environmental references and egocentric observer reference frames were aligned. Here we quantified the effects of manipulating head-centric and retinotopic coordinates on the shape of visual performance fields. When observers viewed briefly presented radial arrays of Gabors and discriminated the tilt of a target relative to homogeneously oriented distractors, performance fields shifted with head tilt (Experiment 1), and fixation (Experiment 2). These results show that performance fields shift in-line with egocentric referents, corresponding to the retinal location of the stimulus

Conscious perception and the modulatory role of dopamine: no effect of the dopamine D2 agonist cabergoline on visual masking, the attentional blink, and probabilistic discrimination

Rationale Conscious perception is thought to depend on global amplification of sensory input. In recent years, striatal dopamine has been proposed to be involved in gating information and conscious access, due to its modulatory influence on thalamocortical connectivity. Objectives Since much of the evidence that implicates striatal dopamine is correlational, we conducted a double-blind crossover pharmacological study in which we administered cabergoline—a dopamine D2 agonist—and placebo to 30 healthy participants. Under both conditions, we subjected participants to several well-established experimental conscious-perception paradigms, such as backward masking and the attentional blink task. Results We found no evidence in support of an effect of cabergoline on conscious perception: key behavioral and event-related potential (ERP) findings associated with each of these tasks were unaffected by cabergoline. Conclusions Our results cast doubt on a causal role for dopamine in visual perception. It remains an open possibility that dopamine has causal effects in other tasks, perhaps where perceptual uncertainty is more prominent