Group differences for voxel-wise probabilistic diffusion tractography contrast (12 cervical dystonia patients versus 12 matched controls).

*<p>Met significance criteria (p<0.00011 [p<0.05 corrected, or t = 4.70] for t values, and 291 voxels for cluster threshold).</p><p>Negative t values indicate that tractography measures were reduced in cervical dystonia patients relative to control subjects. Positive t values indicate that tractography measures were elevated in cervical dystonia patients relative to control subjects. Note that all regions included in the cluster are reported; however, only one peak within the cluster was required to reach statistical significance (t>4.12). t values are reported for all regions exhibiting peaks of 3.5 or greater. L = left hemisphere; R = right hemisphere; wm = white matter.</p

Clinical characteristics of cervical dystonia patients.

*<p>subjects included in 2006 study using different analyses.</p><p>BFM: Burke Fahn Marsden dystonia rating scale.</p><p>Tsui: Tsui rating scale for cervical dystonia.</p><p>TW: Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) for cervical dyston.</p

Regions of probabilistic diffusion tractography that were significantly different between cervical dystonia patients and controls.

<p>(A) shows reduced tractography from the left AL seed region, and (B) shows elevated tractography from the right pallidal seed region. Arrows point to the region through which we drew ROIs in our previous DTI study, which includes AL fibers. <i>A priori</i> segmented regions are shown as reference points: Pink = red nucleus; White = substantia nigra; Blue = pedunculopontine nucleus. MNI talairach coordinates are indicated for each two dimensional image. Lower images in each panel show three dimensional rendering of clusters; the image for the left AL includes the AL seed region in green, and the patient/control difference is shown in blue. t maps and three dimensional clusters are superimposed on the average FA map for all 24 subjects in the study for anatomical reference, and are thresholded at t = +/−2.07 (the threshold used to identify difference clusters, p<0.05, uncorrected, for df = 22). The color bars indicate the range of t values in each panel, from +/−2.07 to the peak t value for each contrast. Warm tones (red, orange, yellow) indicate regions in which cervical dystonia patients exhibited elevated tractography relative to control subjects. Cool tones (blues) indicate regions in which cervical dystonia patients exhibited reduced tractography relative to control subjects. Three dimensional images are shown in mono-color rather than graded/multi-color to illustrate location rather than significance. LH: left hemisphere; RH: right hemisphere.</p

Significant FA differences in cervical dystonia patients relative to control subjects.

<p>(A) Reduced FA in the left cerebellar white matter in patients. (B) Increased FA adjacent to and overlapping with the left substantia nigra in patients. MNI talairach coordinates are indicated for each image. t maps are superimposed on the average FA map for all 24 subjects in the study, and are thresholded at t = +/−2.5 here for illustrative purposes. The color bar indicates the range of t values in this figure for FA contrasts, from +/−2.5 to the peak positive and negative t values for this contrast. Warm tones (red, orange, yellow) indicate regions in which cervical dystonia patients exhibited elevated FA relative to control subjects. Cool tones (blues) indicate regions in which cervical dystonia patients exhibited reduced FA relative to control subjects. LH: left hemisphere; RH: right hemisphere.</p

Group differences for voxel-wise FA contrast (12 cervical dystonia patients versus 12 matched controls).

*<p>Met significance criteria (p<0.00022, [p<0.05, corrected, or t = 4.42] for t values, and 72 voxels for cluster threshold).</p>†<p>p value was within an order of magnitude of the corrected threshold (a trend).</p><p>Positive t values indicate FA values were elevated in cervical dystonia patients relative to control subjects; negative t values indicate FA values were reduced in cervical dystonia patients relative to control subjects. L = left hemisphere; R = right hemisphere; wm = white matter.</p

Probabilistic diffusion tractography and overlap with <i>a priori</i> areas of evaluation (AOEs) used for the FA and MD contrasts.

<p>(A) Examples of tractography from the left ansa lenticularis (AL) seed region, averaged across control subjects (before contrasts were conducted), thresholded at 500 (samples). Note that tractography bifurcated at the level of the substantia nigra (see axial image). (B) Examples of tractography from the left pallidal seed region, averaged across control subjects (before contrasts were conducted), thresholded at 500. Like AL tractography, pallidal tractography bifurcated at the level of the substantia nigra (see axial image). There were also two projections to the thalamus, one superior and one more ventral (see sagittal image). (C) Intersection of tractography with segmentations of our <i>a priori</i> AOEs, including (in descending order) the ansa lenticularis (green), the substantia nigra (white), the red nucleus (pink), the pedunculopontine nucleus (blue), and the superior cerebellar peduncle (peach). Tractography maps are superimposed on the average FA map for all 24 subjects in the study. (D) Example of type Ib GPi neuron from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031654#pone.0031654-Parent1" target="_blank">[21]</a>, showing extensive arborization, including to the RN and PPN (reprinted with permission from The Journal of Comparative Neurology). MNI talairach coordinates are indicated for all images. LH: left hemisphere; RH: right hemisphere.</p