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

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

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

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