Point of Subjective Equality (PSE).

<p>PSE for conditions c₀ (blue), c₁ (red), c₂ (green), c₃ (right slanted stripes) and c₄ (left slanted stripes) in the Duration (left), Surface (center) and Number (right) tasks. Note the gradation between c₁, c₀ and c₂: the larger the Duration and Number of dots, the smaller the Surface estimate and the larger the Duration and Surface, the smaller the estimate for Number of dots. Bars are two s.e.m.</p

Magnitude effect in the retrospective experiment.

<p>When participants were informed of the target magnitude after the display, their RTs in the Duration task (left) were significantly longer than in the Surface task (center). Star (*) indicates a significant difference as a result of a Bonferroni-corrected t-test. Bars are two s.e.m.</p

Mean psychometric curves.

<p>Psychometric curves for controls and conditions c₀ (blue), c₁ (red) and c₂ (green) in the Duration (lower left), Surface (upper right) and Number (lower right) tasks. For display, sigmoid curves use the average fitting parameters across participants (n = 12). <b>Panel A</b>: Prospective Experiment. In the control conditions (upper left), no significant differences were observed when comparing all three magnitudes. <b>Panel B</b>: Retrospective experiment. In the control conditions (upper left), no significant differences were observed when comparing all three magnitudes. Bars are two s.e.m.</p

Distance effect in the prospective experiment.

<p>In all three Duration, Surface and Number prospective tasks, reaction times (RTs) were shorter when target stimuli were close to the anchor stimuli (0.75 and 1.75) than when the stimuli were in-between. Stars (*) indicate significant differences (p<0.05) as a result of Bonferroni-corrected t-tests. Bars are two s.e.m.</p

Experimental procedure.

<p>Panel A: the target magnitudes were either duration (D), space (S) or number (N). For each target magnitude six values were tested to draw reliable psychophysical thresholds: 0.75, 0.9, 0.95, 1.05, 1.1 and 1.25 times the target magnitude's mean value. Each of the six values was tested with five different possible combinations of the non-target magnitudes. Panel B: Prospective experiment. At the outset of a trial, participants were told which magnitude was to be estimated. Panel C: Retrospective experiment. Participants were told only after a given trial which magnitude needed to be estimated.</p

Brain sites of stimulation.

<p>MNI coordinates on the single subject MNI template used to localize the right and left STG.</p

Results.

<p>A) Timeline of the experimental paradigm; B) Percentage of accurate responses and standard errors across the three TMS sites for the duration (white bars) and the frequency (black bars) discrimination tasks. Asterisk indicates significant differences in Tukey’s tests (* p<0.02). In order to check that the two tasks were well matched in terms of difficulty we also compared the two tasks after vertex stimulation (vertex Duration versus vertex Frequency: T₇ = −0.21 P = 0.8). C–E) Group accuracy data (number of hits/total number of targets) across different comparison durations, for rTMS of the vertex (□), right (○) and left (*) STG. The line fitting the symbols are averaged fitted functions (obtained fitting the group averaged data). Solid lines represent rTMS of the vertex, dashed lines rTMS of right STG and dotted lines rTMS of the left STG. C) is the duration discrimination task E) is the frequency discrimination task. D–F) JND (black bars) and PSE (white bars) group data for temporal (D) and frequency (F) discrimination tasks as a function of TMS conditions. Asterisk indicates significant differences in Tukey’s t-tests (* p = 0.04).</p

Magnitude of mean change in visual discrimination sensitivity across groups in the A contrast and B orientation task.

<p>Error bars represent the confidence intervals surrounding the means (CI = 95%). For both tasks, participants assigned in the high SE groups exhibited the greater increase in magnitude in VDS (decrease in discrimination threshold).</p

A schematic diagram of the experimental paradigm.

<p>Left: Contrast Discrimination task, Right: Orientation Discrimination task. Participants made a two-interval forced choice judgment on which temporal interval (i.e. first or second) contained the grating that popped out in contrast (left panel) or orientation (right panel).</p

Scatter-plot of the two partial correlations performed on the A. contrast task and B. orientation task where change in SE was the predictor variable and change in VDS was the predicted variable in the.

<p>Each dot represents one participant. In both tasks SE moderately predict VDS.</p