Une application pour téléphones intelligents facilitant l’accueil au début des stages en unité de soins intensifs

Implication Statement The Department of Critical Care at Dalhousie University developed a smartphone app to improve the quality of learner orientation to the intensive care unit (ICU). The app increased satisfaction with orientation and was perceived as useful. It was ranked as the second most valued resource for orientation after other residents. There is potential to improve the experience of learners with this popular technology.Énoncé des implications de la recherche Le département des soins critiques de l'Université Dalhousie a mis au point une application pour téléphones intelligents en vue d'améliorer la qualité de l’accueil des apprenants à l'unité de soins intensifs (USI). L'application a permis d'augmenter la satisfaction par rapport à l’accueil et elle a été jugée utile. Elle a été classée la deuxième ressource d’orientation la plus appréciée après « les autres résidents ». L'expérience des apprenants peut être améliorée à l’aide de cette technologie populaire

Bistable Percepts in the Brain: fMRI Contrasts Monocular Pattern Rivalry and Binocular Rivalry

The neural correlates of binocular rivalry have been actively debated in recent years, and are of considerable interest as they may shed light on mechanisms of conscious awareness. In a related phenomenon, monocular rivalry, a composite image is shown to both eyes. The subject experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. The experience is similar to perceptual alternations in binocular rivalry, although the reduction in visibility of the suppressed component is greater for binocular rivalry, especially at higher stimulus contrasts. We used fMRI at 3T to image activity in visual cortex while subjects perceived either monocular or binocular rivalry, or a matched non-rivalrous control condition. The stimulus patterns were left/right oblique gratings with the luminance contrast set at 9%, 18% or 36%. Compared to a blank screen, both binocular and monocular rivalry showed a U-shaped function of activation as a function of stimulus contrast, i.e. higher activity for most areas at 9% and 36%. The sites of cortical activation for monocular rivalry included occipital pole (V1, V2, V3), ventral temporal, and superior parietal cortex. The additional areas for binocular rivalry included lateral occipital regions, as well as inferior parietal cortex close to the temporoparietal junction (TPJ). In particular, higher-tier areas MT+ and V3A were more active for binocular than monocular rivalry for all contrasts. In comparison, activation in V2 and V3 was reduced for binocular compared to monocular rivalry at the higher contrasts that evoked stronger binocular perceptual suppression, indicating that the effects of suppression are not limited to interocular suppression in V1

Binocular rivalry minus replay.

<p>(A) Figure follows the same format as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020367#pone-0020367-g006" target="_blank">Figure 6</a>, but shows areas in which the activation for binocular rivalry exceeded rivalry replay. There was greater activation for binocular rivalry in superior (SP) and inferior parietal (IP) cortex, supplementary motor area (SMA), ventral temporal (VT) areas and lateral occipital (LO) areas, including MT+ and lateral occipital complex. (B) Region of interest analysis, as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020367#pone-0020367-g006" target="_blank">Figure 6</a>, but for the subtraction of binocular rivalry minus replay condition in percent signal change. With the replay condition subtracted, binocular rivalry continued to show a U-shaped function of activation as a function of contrast, with higher activation at 9% and 36%.</p

Psychophysical data averaged across all six subjects.

<p>(A) Alternation rates for binocular or monocular rivalry with grating stimuli. There was a slight tendency for alternations to be slower for monocular than binocular rivalry, but this was not statistically significant. (B) Data from the suppression test for binocular or monocular rivalry with grating stimuli. There was a greater change in visibility with alternations for binocular than monocular rivalry, especially at higher contrasts. Error bars are ±1 s.e.</p

Binocular rivalry minus blank baseline.

<p>Figure follows the same format as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020367#pone-0020367-g003" target="_blank">Figure 3</a>, but results are for binocular rivalry (BR) minus the blank baseline condition. (A) As with monocular rivalry, binocular rivalry showed a U-shaped function of activation as a function of contrast; there was higher activation in a number of different areas at 9% and 36%. Abbreviations: inferior frontal cortex (IF); lateral occipital cortex (LO); middle frontal cortex (MF); premotor cortex (PM); superior parietal cortex (SP); supplementary motor area (SMA); temporoparietal junction (TPJ). (B) The region of interest analysis also confirmed that binocular rivalry showed a U-shaped function of activation as a function of contrast in many areas, particularly V2 and V3.</p

Stimuli used in the fMRI and psychophysics experiments.

<p>(A–B) Left and right oblique gratings used for dichoptic presentation in binocular rivalry. (C) Composite grating stimulus presented to both eyes for monocular rivalry. (D) Baseline blank condition.</p

Correlations between activation for (A) monocular rivalry or (B) binocular rivalry and alternation rates.

<p>Correlations were performed between activation levels (% signal change minus baseline blank condition) and alternation rates for the six subjects obtained during the fMRI scan sessions. The correlations shown for monocular rivalry are for 36% contrast gratings, while the correlations for binocular rivalry are for 18% contrast gratings. Correlations are shown for areas V2 and V3 (average of left and right hemisphere), and in all four cases were statistically significant with correlation coefficients (r-values) of 0.82 and greater (p<0.05). For monocular rivalry, the activation levels increased with faster alternations, while the opposite effect occurred with binocular rivalry.</p

Binocular rivalry minus monocular rivalry.

<p>(A) Areas in which the activation for binocular rivalry exceeded that for monocular rivalry, shown for the three contrasts (9%, 18% and 36%). There was greater activation for binocular rivalry in occipital pole regions at the lowest contrast, but this reversed at higher contrasts. Note that the occipital pole (OP) is circled in white on a lateral and ventral view. Generally there was greater activation for binocular rivalry in superior parietal cortex (SP), inferior parietal cortex (IP) close to the temporoparietal junction, supplementary motor area (SMA), ventral temporal areas (VT) and lateral occipital (LO) areas including MT+ and lateral occipital complex. (B) Region of interest analysis. Binocular rivalry minus monocular rivalry in percent signal change (average of six subjects). The analysis for V1, V2 and V3 was carried out only in the foveal part of each area (0–2.9 deg eccentricity). Generally, the results did not differ between the left and right hemisphere, and have been averaged, except for area V1, for which the results are shown separately. There was greater activation for binocular rivalry in areas V2 and V3 at the lowest contrast, but this reversed at higher contrasts.</p

Alternation rates (reversals/s) during the scan session (averaged across six subjects), for binocular or monocular rivalry at the three contrasts (9%, 18%, 36%).

<p>Alternation rates (reversals/s) during the scan session (averaged across six subjects), for binocular or monocular rivalry at the three contrasts (9%, 18%, 36%).</p

Monocular rivalry minus blank baseline.

<p>(A) Activation for monocular rivalry (MR) with grating stimuli above the blank baseline condition at the three contrasts (9%, 18%, 36%). The lateral, ventral and medial views of the inflated brain are shown (right hemisphere only). Colour scale on this and subsequent Figures indicates statistically significant results ranging from t = 2.35 to 8.00 (orange-yellow) (FDR, p<0.05). Monocular rivalry showed a U-shaped function of activation as a function of contrast; there was higher activation in a number of different areas at 9% and 36%. Abbreviations: dorsolateral prefrontal cortex (DLPF); inferior parietal cortex (IP); occipital pole (OP); premotor cortex (PM); superior parietal cortex (SP); supplementary motor area (SMA); ventral temporal (VT); ventrolateral prefrontal cortex (VLPF). (B) Region of interest analysis for monocular rivalry, in terms of percent signal change above the blank baseline condition (average of six subjects). The results are shown for gratings at the three contrasts (9%, 18%, 36%). The analysis for areas V1, V2 and V3 was carried out only in the foveal part of each area (0–2.9 deg eccentricity). Generally, the results did not differ between the left and right hemisphere, and have been averaged. Statistically significant results (p<0.05) in this and subsequent Figures are labeled with an asterisk. As in panel (A), monocular rivalry showed a U-shaped function of activation as a function of contrast in many areas, particularly V2 and V3.</p