Accurate responses as a function of chronotype, testing time and block for the precision strategy condition.

<p>Each chronotype showed marked performance decrements at the non-optimal testing time. Vertical bars denote +/− standard error of the mean.</p

Sequence of events for both strategy conditions in the modified SART.

<p>The precision strategy condition, on the left, emphasised accurate response inhibition over fast responding. Digits turned red when the average correct response rate in no-go trials was below 0.71. The speed strategy condition, on the right, emphasised fast over correctly inhibited responses. Digits were presented in yellow when the average RT was above 440 ms and accuracy rate in no-go trials was not below 0.45.</p

Mean reaction times on the PVT for both chronotypes depending on time of day.

<p>Each chronotype responded fastest at their optimal time of day and slowest at their non-optimal testing time. Vertical bars denote +/− standard error of the mean.</p

Correlation between RT in the PVT and accuracy on SART for the precision strategy condition.

<p>Correlation between RT in the PVT and accuracy on SART for the precision strategy condition.</p

WT pattern after constant routine approach.

<p>Demasked WT waveforms obtained using the constant routine approach (see the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061142#s2" target="_blank">material and methods</a> section for details), employing either purification by categories (A) or by intercepts (B); in the latter case, three different environmental temperatures (15°, 20° and 25°C) are considered. The shaded area shows the mean sleep period. Data are expressed as Mean ± SEM. The values for Mesor, Amplitude and Acrophase as well as the %V of wrist temperature demasked by the simulated constant routine are expressed as Mean±95% Confidence Interval and are included at the bottom of the graph. * indicates p<0.001 according to the cosinor analysis.</p

WT pattern purified for activity.

<p>Demasked WT pattern, expressed as mean ± SEM after application of the purification by intercepts or categories method (correcting for the effect of activity). The shaded area shows the mean sleep period. The table below the graph shows the corresponding Mesor, Amplitude and Acrophase as well as the %V for WT, demasked by means of the purification by categories or intercepts method, (data are expressed as Mean±95% Confidence Interval). * indicates p<0.001 according to the cosinor analysis.</p

Circadian modulation of masking variables.

<p>Circadian modulation of the polynomial coefficients for the different masking variables: (A) light and environmental temperature (Env Temp), (B) activity and position and (C) sleep. The independent term for WT is represented in D. The shaded area shows the mean sleep period. Note that the independent term corresponds to an environmental temperature of 0°C. All values are expressed as Mean ± SEM. See the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061142#s2" target="_blank">materials and methods</a> section for details.</p

TAP simulations.

<p>On the first column, TAP patterns obtained from simulations performed on Syntesi (Diez-Noguera, Barcelona, 2007) are shown. These simulations are drawn on black and subject's real TAP pattern on red. The noise percentage employed for modelisation (% noise) and percentage of instability in rest-activity ratio (R-A Ins) are shown in the second and third columns, respectively. Calculations of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA) and circadian function index (CFI) for every model or real case are also indicated. Note that IS, IV, RA and CFI's units are AU. Green shadow indicates simulations performed on squared waves under different noise levels (while the same R-A Inst is maintained) and subject's real TAP pattern. Yellow shadow indicates simulations performed on squared waves under a 20% of R-A Inst and two extreme noise levels. Orange shadow indicates simulations performed on sinusoidal waves under two different noise levels (while the same R-A Inst is maintained).</p

Individual weekly recording of all variables.

<p>Wrist temperature (A) in red, motor activity (B) in green, body position (C) in orange and TAP (D) in violet of a subject taken as an example, on the left. On the right it is represented the mean waveform of every variable for the same subject. Shaded blue areas coincide with sleep declared by subjects. On the right every variable is represented as value ± SEM.</p

Correlations between every variable with respect to rest declared by subjects.

<p>Wrist temperature (A), motor activity (B), body position (C) and TAP (D). Please note correlations coefficients and its probability value on the upper right of every pannel.</p