k_2a (the ligand washout constant in relation to the total amount of radioactivity in the target tissue) increased significantly in the right caudate in the Incongruent condition in ADHD but not in the healthy control group.

<p>NS = non significant.</p

MNI coordinates the striatal areas where significant changes in the rate of ligand displacement were observed in the Incongruent condition.

<p>The table also shows the t-values of the difference in displacement rates observed in the Congruent and Incongruent condition. The data suggests that the locations were almost identical in the ADHD and healthy control volunteers (in the putamen and left caudate) but the changes (t-values) were greater in ADHD.</p

DTI/Hearing Threshold Correlations.

<p>DTI SPM results for all experimental correlation for hypothesized regions: splenium of the corpus callosum (splenium), body of the corpus callosum (CC), lateral lemniscus/superior olivary complex level of the brain stem (LL/SOC), pulvinar thalamus (Pulv. Thal.). Auditory Associative (Aud Assoc.) regions were not hypothesized because of the size of the region. 8^th nerve was not hypothesized because we anticipated very small alignment issues would hinder the findings.</p

Comparison of the mean ligand binding potentials (BP) estimated at rest in ADHD and healthy control volunteers (ADHD>control).

<p>The BP was significantly greater in ADHD volunteers in the right caudate suggesting reduced tonic release of dopamine in this area.</p

MNI coordinates of the maximum values of the ligand BP measured at rest in ADHD and healthy control volunteers in the caudate and putamen.

<p>MNI coordinates of the maximum values of the ligand BP measured at rest in ADHD and healthy control volunteers in the caudate and putamen.</p

Comparison of the ligand BP in ADHD and healthy control volunteers in the Incongruent condition (healthy control >ADHD).

<p>The comparison revealed significantly higher BP in the right caudate of ADHD volunteers. The MNI coordinates of the maxima were, x,y,z = 12,16,6).</p

Regions of negative correlation between DTI FA measures and signal detection thresholds are shown for N0S0, N0SL, N0SR, N0Sπ, and NπS0.

<p>These show regions where tracts are more directional (anisotropic) with better thresholds. While there is a bilateral pattern revealed for N0S0, N0SL, and N0SR, there is no activation seen in this region for N0Sπ and NπS0. Each image is a coronal view, with the MNI template Y coordinate = 13 mm; this location was selected based on a finding of activity between N0Sπ and NπS0 in our previous study within the corpus callosum. A lenient threshold of p<.1, was used to show the potential full extent of the involved regions. Images are displayed with patient's left on the left side of the image, an “L” marks the patient's left on the first image.</p

The ligand BP in ADHD and healthy control volunteers in Incongruent condition.

<p>ADHD volunteers had lower BP in all striatal areas (suggesting higher amount of dopamine release) but the difference was significant (p = 0.004) only in the right caudate. RC = right caudate, LC = left caudate, RP = right putamen, LP = left putamen.</p

Red color indicates increased activity for dichotic condition versus N0S0.

<p>Blue indicates increased activity for N0S0 versus the dichotic condition. The overall patterns for N0Sπ vs. N0S0 (left image) and NπS0 vs. N0S0 (right image) are similar within the left auditory cortex. Regions are threshold at p<.01, uncorrected. Images are spatially normalized to SPM MNI template, but have been rotated (pitch) by .38 radians, to enable the view of the three regions of activation within the axial view. Orthogonal slices were selected to pass through the region of activation for N0Sπ – N0S0 (MNI coordinates: −52, −30, 1 mm) and NπS0 – N0S0 (MNI coordinates: −47, −27, −2 mm).</p

Increased ligand binding potential (BP) during task performance.

<p>In ADHD volunteers the ligand BP increased significantly in the caudate and putamen bilaterally in Incongruent condition which required inhibition of unwanted responses.</p