Parameters and coefficient of determination for the best fits of Eqs. 3 and 5 to the data of effort-insensitive monkeys.

<p>The fits corresponding to these parameters are plotted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048434#pone-0048434-g002" target="_blank">Figure 2B</a>. Average reports mean ± SD.</p

Behavioral paradigm. A

<p>Sequence of events during a trial of the work/delay task. A monkey initiated a trial by touching the bar in the chair, 100 ms later a visual cue (13° on a side), which will be described below, was presented at the centre of the monitor. After 500 ms, a red target (0.5° on a side) also appeared at the centre of the monitor. After a variable interval of 500–1,500 ms, the target turned green, indicating that the monkey could release the bar for correct performance. If the monkey responded between 200 and 1,000 ms, the target turned blue indicating the trial had been completed correctly. On correct trials, one drop of water reward was delivered immediately or after a delay (3.6 s or 7.2 s). An inter-trial interval (ITI) of 1 s was enforced before the next trial could begin. If the monkey made an error by releasing the bar before the green target or within 200 ms after the green target appeared or failed to respond within 1 s after the green target, all visual stimuli disappeared, the trial was terminated immediately, and, after the 1-s ITI, the trial was repeated. <b>B</b> Relationships between visual cues and trial schedule in the work trials. <b>C</b> Relationship between visual cues and delay duration in the delay trials. Trials on green boxed were used for the analysis. CU denotes the remaining cost (arbitral unit) to get reward, that is, either remaining workload to perform trial(s) or remaining delay periods (equivalent to a trial). It corresponds the number of red boxes placed to the reward.</p

Reaction time (mean ± SEM) as a function of remaining costs.

<p><b>A</b> Effort-sensitive monkeys. <b>B</b> Effort-insensitive monkeys. Red triangles and black circles are work and delay trials, respectively.</p

Parameters and coefficient of determination for the best fits of Eqs. 3 and 5 to the data of effort-sensitive monkeys.

<p>The fits corresponding to these parameters are plotted in Figure 2A. Average reports mean ± SD. There is significant difference between <i>k_w</i> and <i>k_d</i> (<i>p</i><0.05, paired t-test with logarithmic transformation).</p

Bar touch movements during delay periods (mean ± SEM). A

<p>Effort-sensitive monkeys. <b>B</b> Effort-insensitive monkeys.</p

Error rates (mean ± SEM) as a function of remaining costs.

<p><b>A</b> Effort-sensitive monkeys. <b>B</b> Effort-insensitive monkeys. Red triangles and black circles are work and delay trials, respectively. Black and grey lines are best fit lines for Eqs. 3 and 5, respectively.</p

Regression lines between BP_ND, locomotion, and cumulative MPTP dose.

<p>The relationship between the binding potential (BP_ND) of [¹¹C]PE2I in the putamen or caudate and the daily locomotion count (relative to pre-MPTP counts) after cumulative MPTP administration was determined using the least squares method and is presented in the upper graphs. The relationship between BP_ND in the putamen or caudate and the cumulative MPTP dose is presented in the lower graphs.</p

Representative parametric images.

<p>Coronal sections illustrating the binding potential (BP_ND) of [¹¹C]PE2I in the brains of MPTP-free and MPTP-treated marmosets are presented.</p

Radioactivity versus time curves in the brains of MPTP-free and MPTP-treated marmosets.

<p>A dopamine transporter ligand, [¹¹C]PE2I, was intravenously administered to marmosets. The putamen and caudate in the striatum were the target regions, and the cerebellum was a reference region.</p

Binding potentials (BP_ND) of [¹¹C]PE2I.

<p>Binding potentials in the striatum (putamen and caudate) of brains of MPTP-treated and MPTP-free common marmosets are presented.</p>#1<p>:Ratios of mean daily locomotion counts of the post-MPTP period to those of pre-MPTP period (mean ± SD).</p>#2<p>:MPTP cumulative doses (mg/kg).</p>*<p>:p<0.05 against MPTP-free marmosets (Bonferroni test). SD: Standard deviation.</p