Demographic and clinical characteristics of participant groups.

<p><b>Education</b>: education duration in years. <b>ACE-R</b>: Addenbrooke's cognitive examination revised. <b>MMSE</b>: Mini-Mental State Examination score. <b>BDI</b>: Beck depression inventory II. <b>H&Y</b>: Hoehn & Yahr stage. <b>UPDRS</b>: Unified Parkinson's disease rating scale. p-values refer to chi-squared tests or unpaired student t-tests as appropriate (uncorrected).</p

Stepwise linear regression for the four impulsivity factors and clinical or demographic variables.

<p>For each row, the impulsivity factor corresponds to the four factors in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0085747#pone-0085747-t005" target="_blank">table 5</a>. UPDRS: Unified Parkinson's disease rating scale. ACE-R: Addenbrooke's cognitive examination revised. LED: levodopa dose equivalent.</p

The multiple modes of impulsivity model.

<p>We propose that there are multiple modes of impulsivity in Parkinson's disease (Imp1, Imp2, etc.) which are driven by differential changes in brain structure (white matter, WM, and grey matter, GM), and changes in noradrenergic (NA), cholinergic (Ach) and dopaminergic (DA) neurotransmission. These separate modes reflect the ontology of impulsivity in health, and distinctive neural circuits for impulse control with partially selective pharmacology.</p

Component matrices from the whole-group principal components analysis (controls and Parkinson's disease patients), showing the percentage of variance explained by each orthogonal impulsivity factor and their eigenvalues.

<p>Loadings of each task on the four factors are shown after varimax rotation, and shown in bold above the threshold 0.5.</p

Summary of neurotransmitter associations with performance on tests of inhibition or impulsivity.

<p>+: Evidence of significant influence of the neurotransmitter on the test score.</p><p>−: Evidence of probable lack of influence of the neurotransmitter on the test score.</p><p>+−: Inconsistent or equivocal evidence of influence of the neurotransmitter on the test score.</p><p>^# Lack of evidence of any specific effect of the neurotransmitter on the test score (for details of each test, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0085747#pone-0085747-t002" target="_blank">Table 2</a>).</p><p>Citations correspond to studies in PD patients, otherwise marked as,</p><p>Patients with other diseases;</p><p>^h healthy controls;</p><p>rodents.</p

Impulsivity variables in patients and controls, showing multiple univariate comparisons (Student t-tests, uncorrected for multiple comparisons) for the scalar variables derived from the tests in table 2.

<p>The SOGS and MIDI scores were excluded due to the scarcity of positive responses.</p

Mean frequency of responses (A) and reaction time (B) in Experiment 1 rating task.

<p>Ratings 1, 4 and 7 denote very unpleasant, neutral and very pleasant valence, respectively. Error bars are one standard error of the mean values. OCD, Obsessive Compulsive Disorder.</p

Mean frequency of responses (A) and reaction time (B) in Experiment 2 rating task.

<p>Ratings 1, 4 and 7 denote very unpleasant, neutral and very pleasant valence, respectively. Error bars are one standard error of the mean values. OCD, Obsessive Compulsive Disorder.</p

Mean reaction times for target absent (A) and target present (B) trials in Experiment 1.

<p>Error bars are one standard error of the mean values. </p

5-CSRTT.

<p>Performance of alcohol-preferring rats (P, closed squares) and alcohol-non-preferring rats (NP, open circles) in the 5-CSRTT, during baseline sessions (ITI = 5s) and during the long ITI challenge session (ITI = 7s) before and after the 4-week alcohol intake. Data are means ± SE of % premature responding (a), attentional accuracy (b), % omissions (c), correct response latency (d), food magazine latency (e) and time spend nose-poking in the food magazine (f). All p<0.05: (≠) vs baseline A, (σ) vs previous sessions; (*) significant difference between P and NP rats in the same session; (•) vs baseline A in P rats, (∞) vs baseline A and B; (x) versus pre-alcohol sessions in NP rats.</p