9 research outputs found

    Changes in diffusion tensor imaging (DTI) indices of white matter microstructure after sleep deprivation and associations with sleepiness.

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    <p>(<b>A</b>) Significant decreases in fractional anisotropy (FA) after sleep deprivation (blue colors; left panel). (<b>B</b>) Significant decreases in axial diffusivity (AD) after sleep deprivation (blue colors; left panel). Averaged DTI values at time point (TP)2 and TP3 across significant voxels are shown for each participant using individual colors in the right panels of (<b>A</b>) and (<b>B</b>). Values from the same participant are connected with a line. (<b>C</b>) No significant relationship was observed between the decrease in FA in the voxels shown in (<b>A</b>) and Stanford Sleepiness Scale (SSS) score at TP3 (<i>R</i> = ‚ąí0.33, <i>P</i> = 0.14). (<b>D</b>) Because the FA decreases in the significant voxels of (<b>A</b>) were mainly driven by AD reductions, we examined whether reductions in averaged AD within these clusters correlated with SSS score and found a significant negative association (<i>R</i> = ‚ąí0.63, <i>P</i> = 0.002), indicating greater sleepiness in subjects with larger AD reductions after sleep deprivation. (<b>E</b>) No significant relationship was found between AD reductions across the voxels shown in (<b>B</b>) and SSS score (<i>R</i> = ‚ąí0.26, <i>P</i> = 0.265). (<b>F,G</b>) Averaged AD across all voxels of the white matter skeleton decreased significantly from TP2 to TP3; this decrease was significantly correlated with sleepiness at TP3 (<i>R</i> = ‚ąí0.65, <i>P</i> = 0.001). The left side of the brain images represents the right hemisphere.</p

    The relationship between orienting and HRV.

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    <p>Plots demonstrate the relationship between orienting and HRV at baseline (3A) after sleep (3B) and after sleep deprivation (3C). The blue histogram shows the posterior distribution for the correlation <i>p</i> with a 95% highest density interval (HDI). The scatterplots illustrate the relationships between these two variables, with superimposed posterior predictive distributions. The larger light blue ellipse shows the 95% highest density region while with smaller dark blue ellipse shows the 50% highest density region. The histograms on the top x-axes and right y-axes show the marginal distributions of the data. HDI = Highest density interval.</p

    A matrix of plots illustrating the agreement of HRV between three time points.

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    <p>The upper right panels consist of scatterplots with identity line (45¬į line though the origin). The lower left panels consist of Bland-Altman plots with confidence bounds and bias (dotted red line) and the horizontal black line passing through the origin. The confidence bounds show the mean of the difference between time points plus or minus twice of the standard deviation of the difference.</p

    Main effects and interactions of group and measurement period on heart rate variability, heart rate, and ANT measures.

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    <p>Line graphs illustrate means and 95% confidence intervals for log-transformed HF-HRV (1A), HR (1B), mean reaction time (1C), Orienting t-values (1D), Alerting t-values (1E), and Conflict t-values (1F). Error bars represent 95% confidence intervals, which are corrected to remove between-subject variability. M1 = Morning 1; N1 = Night 1, M2 = Morning 2.</p