Grand-averaged vocal responses by group.

Grand-averaged vocal responses to upward (top) and downward (bottom) pitch shifts for the a) opposing, b) following, and c) non-varying groups (blue line represents pre-training responses, red line represents post-training responses).</p

P2 latency and amplitude.

The a) mean P2 peak latency and b) mean P2 peak amplitude from the ERPs at Cz for the opposing (Opp), following (Fol), and non-varying (Non) groups pre-training (solid bars) compared to post-training (slanted lines). Bars represent standard error of the mean.</p

Grand-averaged ERP waveforms and ERP scalp distribution results elicited by the Up shift of the F0.

<p>Left panel represents ERPs elicited in predictable and unpredictable experimental conditions measured at two electrode sites that were submitted for statistical analyses. Blue vertical bar depicts time window at which the mean amplitude of the ERP difference wave was measured for the statistical analyses. Right panel represents scalp distribution of N1 response in predictable (top) and unpredictable (middle) experimental conditions as well as the scalp distribution of the ERP difference wave (bottom).</p

Grand-averaged ERP waveforms and ERP scalp distribution results elicited by the Down shift of the F0.

<p>Left panel represents ERPs elicited in predictable and unpredictable experimental conditions measured a two electrode sites that were submitted for statistical analyses. Blue vertical bar depicted time window at which the mean amplitude of the ERP difference wave was measured for the statistical analyses. Right panel represents scalp distribution of N1 response in predictable (top) and unpredictable (middle) experimental conditions as well as the scalp distribution of the ERP difference wave (bottom).</p

Voice perturbation paradigm and behavioral study results.

<p>(A) Schematic illustration of voice output and perturbation stimuli. (B) Schematic representation of experimental conditions showing upward and downward pitch shifts in the unpredictable (top) and predictable conditions (bottom 2 rows). (C) Behavioral (voice) results. Grand-averaged F0 traces across all subjects separately for “Up” and “Down” stimuli with unpredictable and predictable experimental conditions. Thick lines show opposing and thin lines “following” responses. Vertical bars illustrate standard deviations of the averaged F0 traces. Vertical dashed lines represent pitch shift stimuli onset.</p

Group average difference waveforms corresponding to gating difference waveform (GDW) obtained from normal sleepers (NS), habitual short sleeping subjects (SS) after their habitual sleep (hSS) and extended sleep (eSS).

<p>(B) Topographic scalp distribution of GDW for each group and sleep condition. The open circles on the maps indicate the electrodes selected for comparison of the GDW amplitude and statistical evaluation. The selected time latencies corresponding to the largest peak of the averaged GDW waveforms calculated for each group and sleep condition. The red color indicates the positive polarity and the blue color indicates the negative polarity of the GDW waveform.</p

One Week – Sleep Diary (Mean ± SD) Obtained from Normal Sleepers, Habitual Short Sleepers, and Extended Sleep Condition.

<p>TIB  =  time in bed, TST  =  total sleep time, LTS  =  latency to sleep, SE  =  sleep efficiency.</p

The means and SDs for peak amplitude of the P50 response at Cz electrode to click-sound S1 for each group (NS, SS) and sleep condition (hSS and eSS).

<p>The means and SDs for peak amplitude of the P50 response at Cz electrode to click-sound S1 for each group (NS, SS) and sleep condition (hSS and eSS).</p

Grand average of the P50 waveforms corresponding to S1 (black line) and S2 (red line) obtained from normal sleeping (NS) and habitual short sleeping (hSS) individuals.

<p>Illustration of changes in P50 amplitude after one week of sleep extension in habitual short sleeping (eSS) individuals is on the bottom of the figure.</p