Comparison of activity for calendrical tasks and division with their respective control tasks.

<p>A voxel-level threshold of p<.001 uncorrected was applied (min. 30 voxels cluster extent). Peak co-ordinates, expressed in millimetres, refer to MNI space.</p

Regions of Interest (ROIs).

<p>ROIs derived from the Automated Anatomical Labelling atlas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073746#pone.0073746-TzourioMazoyer1" target="_blank">[32]</a> used for time-course extraction. Centroid co-ordinates, expressed in millimetres, refer to MNI space. All ROIs are symmetric between hemispheres. Volumes are given in millilitres.</p

Comparison of activity for remote and close dates.

<p>A voxel-level threshold of p<.01 un-corrected was applied. Superscript “*” next to cluster volumes (expressed in millilitres) denotes cluster-level significance at p<.01 un-corrected (min. 10 voxels cluster extent). Peak co-ordinates, expressed in millimetres, refer to MNI space.</p

Behavioural and physiological responses for the different tasks and difficulty levels.

<p>(<b>a</b>) Perceived difficulty of calendric trials based on YV's ratings after the scan (scale 0–2, where 0 is easy, 1: challenging, 2: very difficult). (<b>b</b>) Reaction times in seconds. First 3 bars correspond to calendric task, 4^th bar to the calendric control task, 5^th to division task and 6^th to division control task. (<b>c</b>) Response accuracy for close dates: 97%, for intermediate dates: 82%, for remote dates: 77%, for the control task: 96%. Response accuracy for the division task was comparable to the performance for close dates at 94%, while accuracy for the control division condition was at 98%. (<b>d</b>) Heart rate in beats per minute (b.p.m.). Blocks containing close dates were perceived as significantly less challenging that those presenting intermediate or remote dates, and elicited shorter reaction times. Heart rate closely followed this pattern, but differences did not reach statistical significance. Error bars denote 1 standard deviation across blocks. Significance values are Bonferroni corrected over condition comparisons.</p

Univariate analysis results.

<p>a) Comparison of close, remote dates (calendrical task) and division task with their respective control conditions, shown at p<.001 un-corrected. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073746#pone-0073746-t002" target="_blank">Table 2</a>. b) Comparison of close and remote date calculation trials, shown at p<0.01 uncorrected. Cold colours represent the contrast close>remote, warm colours the contrast remote>close. The sections shown correspond to MNI z = −33, −26 … 58 mm. R: right hemisphere, L: left hemisphere. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073746#pone-0073746-t003" target="_blank">Table 3</a>.</p

Brain regions with indegree higher than random graphs.

<p>Comparison of indegree between the observed effective connectivity networks and 30 corresponding Erdös–Rényi (ER) random graphs matched for completeness. Only nodes having a number of incident connections significantly larger than the random graphs are listed. All p-values are Bonferroni-corrected accounting for 68 comparisons over the whole ROI set.</p

Example trials for the calendrical task (a) and its control (b), and for the division task (c) and its control (d) as they appeared on the screen.

<p>L and R, correspond to left and right response button respectively. See section 2.2 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073746#s2" target="_blank">Methods</a>, Experimental tasks, for detailed descriptions.</p

Example of gamble presentation.

<p><i>kwin</i> represents potential gain, <i>pwin</i> the probability of winning, <i>kloss</i> potential loss. Participants were instructed to consider these elements together and equally weight them when deciding whether to bet or leave each gamble. A third of the gambles had positive EV (risk-advantageous), a third negative EV (risk-disadvantageous) and the remaining EV≈0 (risk-indifferent). The clock spun at two different rates: slow or fast. Participants were explicitly instructed that they always had 5 s to respond. Trials were interspersed with null events (fixation cross).</p

Main effects of EV (whole brain analysis).

<p>No significant effects were observed for the contrasts not reported in this table. The parameter <i>k_E</i> represents the number of 2×2×2 mm voxels in the cluster.</p

Whole-brain fMRI results for the main effect of EV.

<p>Activations shown at the cluster-forming threshold p<0.001. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020942#pone-0020942-t001" target="_blank">Table 1</a> for full list of activation clusters and corresponding extents.</p