a: SPM images of brain dopamine changes.

<p>Significant activated clusters show dopamine (DA) changes in nucleus accumbens for the contrast glucose > sucralose intake (<b>Δ</b>BP_ND). Note that increases in BP_ND reflect DA decreases (less competition from DA for [¹¹C]raclopride to bind to D2/D3 receptors) whereas decreases in BP_ND reflect DA increases with glucose (as compared to sucralose) The SPM images were superimposed onto T2 weighted MR images in sagittal (left upper), coronal (right upper) and transverse (lower) views. The color bar indicates <i>t</i>-score values. <b>b: Correlation between BMI and brain DA changes.</b> The differences between DRD2 availability after the glucose and the sucralose intake (<b>Δ</b>BP_ND) were compared with BMI (kg/m²). The leaner subjects showed the largest DRD2 decreases with glucose in nucleus accumbens (consistent with DA increases) whereas the heavier subjects showed DRD2 increases (consistent with DA decreases). <b>Δ</b>BP*: corrected for changes in blood glucose levels (glucose – sucralose) within PET acquisition (0–60min).</p

Regional glucose metabolism (µg/100 g/min) when subjects were tested during the neutral non-task with placebo (control condition), cognitive task with MP and cognitive task with placebo.

<p>Data corresponds to mean and standard deviation. Subscripts correspond to paired t-test comparisons with respect to the control condition:</p>a<p>p<0.05, ^b p<0.01, ^c p<0.005, ^d p<0.001. The last column corresponds to the significance level for comparison between the cognitive task when given with MP or when given with placebo (PL).</p

Brain activation with the task after placebo (PL) and after methylphenidate (MP).

<p>A. SPM results showing the areas that had increases in metabolism for the cognitive task with placebo versus the control conditions; B. SPM results showing the areas that had increases in metabolism for the cognitive task with MP versus the control conditions. Comparisons correspond to paired t tests (p<0.001 uncorrected >100 pixels). None of the brain regions had higher metabolism for the control condition (neutral non-task with placebo) than for the cognitive task conditions.</p

Differences in brain metabolic activation to the task (percent change) when given with MP when compared with placebo (PL) between subjects in whom MP attenuated brain activation versus those in whom it enhanced activation along with their baseline metabolic measures.

<p>Two subjects showed no differences between MP and placebo (data not included). Comparisons correspond to chi square for the subject numbers (Ss) and to student t-tests (unpaired, two test) for the other comparisons.</p

Differences in task activation between placebo (PL) and methylphenidate (MP).

<p>SPM results showing the areas that had greater increases in metabolism when the cognitive task was given with placebo versus when it was given with methylphenidate (MP). Comparisons correspond to paired t-tests (p<0.005 uncorrected >100 pixels). None of the brain regions had higher metabolism for the cognitive task when given with MP than with placebo.</p

Schematic diagram of experimental procedure.

<p>Placebo (PL) or methylphenidate (MP) was given 60 minutes prior to initiation of Cognitive or Neutral tasks, which lasted 45 minutes. [¹⁸F]FDG was injected 15 minutes after task initiation (75 minutes after MP or PL) and scans were started 35 minutes after injection.</p

Attention rating scales of control subjects in baseline (BL) and in 12 months follow-up (FU) and ADHD subjects prior to (BL) and after 12 months oral methylphenidate treatment (FU).

<p>*CAARS: Conners Adult Attention Rating Scale.</p><p>*SWAN: Strengths & Weaknesses of ADHD Symptoms & Normal-Behaviors.</p><p>*NS: not significant.</p

Clinical characteristics of control subjects and ADHD subjects.

<p>*Ethnic (A: Asian, B: African American, C: Caucasian American, H: Hispanic American, M: More than one race).</p><p>*NS: not significant.</p

Averaged dopamine transporter availability images.

<p>Averaged dopamine transporter availability images of ADHD (n = 18) and control (n = 11) subjects prior to and after 12 months oral MP treatment as well as baseline and 12 follow up scans of control subjects. The images are scaled with respect to the maximum value (distribution volume ratio) obtained on the ADHD subjects at follow up visit and presented using the rainbow scale. Red represents the highest value and dark violet represents the lowest value.</p

Measures [mean (SD)] of dopamine transporter availability (BP_ND) of control subjects at baseline (BL) and 12 months follow-up (FU) and ADHD subjects prior to (BL) and after 12 months oral methylphenidate treatment (FU).

<p>Comparison between BL and FU scans.</p