Decrease of the white matter volume in LDH patients relative healthy controls.

<p>(<i>p</i><0.0001, uncorrected for multiple comparison, cluster threshold of 15 voxel) The group analysis showed decreased subcortical white matter volumes adjacent to the left prefrontal cortex (PFC), the right premotor cortex (PMC) and the anterior limb of the left internal capsule (IC). [Images are presented in neurological convention].</p

Decrease (blue) and increase (red) of gray matter volume in LDH patients relative to healthy controls.

<p>(<i>p</i><0.0001, uncorrected for multiple comparison, cluster threshold of 15 voxel) The group analysis showed decreased gray matter volumes in the right anterolateral prefrontal cortex (alPFC), the right middle temporal gyrus (MTG), the left premotor cortex (PMC), the right caudate nucleus (CN), and the lobule VIIa (Crus I) of the right cerebellum (LVIIa). Increases were found in the right dorsal anterior cingulate cortex (dACC), the left lateral precuneal region (PCu), the left fusiform gyrus (FusG), and the nucleus reticularis of the right brainstem at the level of the basal pons (nRet). Bilateral increases as well as decreases are shown in the orbitofrontal cortex (OFC). [Images are presented in neurological convention].</p

Significant gray and white matter changes in LDH patients relative to healthy controls.

<p>Significant gray and white matter changes in LDH patients relative to healthy controls.</p

ROI-based parameter estimates and FIR time courses.

<p>(<b>A</b>) The analysis of parameter estimates (beta values) revealed enhanced activity in the left SC during saccades into the right visual field and vice versa, as well as enhanced SC activity for centrifugal as compared to centripetal saccades. Data are collapsed across hemispheres displaying collicular activity contralateral (contra) and ipsilateral (ipsi) to the saccade direction. Leftward saccades are considered to be contralateral with respect to the right SC, and ipsilateral with respect to the left SC. Similarly, rightward saccades are considered contralateral and ipsilateral with respect to the left and right SC, respectively. (<b>B</b>) At the same time, centrifugal saccades were associated with a robust prefrontal deactivation that was significantly smaller during centripetal saccades. Data are collapsed across hemispheres and saccade direction. The corresponding ROI-based time courses closely match the differences in parameter estimates within SC (<b>C</b>) and mPFC (<b>D</b>). ROIs were defined orthogonally to condition-specific patterns, i.e. anatomically regarding the SC and on the basis of the contrast <i>‘all saccades versus fixation’</i> within mPFC. Representative ROI locations are displayed on a single-subject's T1-weighted image in the center. Error bars in panels A and B depict the standard error (SE) in each condition across subjects.</p

Paradigm and fMRI-acquisition volume.

<p>(<b>A</b>) Subjects performed saccades away from (centrifugal) and towards (centripetal) the screen center. Centrifugal saccades were cued by a central color change (300 ms), symbolically indicating the direction of the saccade (e.g., blue equals right vs. green equals left). After each centrifugal saccade, the gaze remained at the designated lateral square until a black cross indicated to perform a centripetal saccade back to the center. In fixation trials, indicated by a third cue color (e.g., red), subjects' gaze remained at the center position. The stimulus onset asynchrony (SOA) was jittered between 1500 and 7500 ms for all centrifugal and centripetal cues to facilitate the deconvolution of the event-related fMRI responses. (<b>B</b>) Functional images were acquired as a partial-head volume covering the upper brainstem including the SC, as well as large portions of the occipital and prefrontal cortex. The layout of the 24 functional image slices is superimposed on a single-subject's T1-weighted anatomical scan.</p

Saccade-related BOLD activity.

<p>(<b>A</b>) Saccade execution was associated with robust activity in bilateral medial occipital cortex, putamen, pulvinar, and LGN as compared to cued fixation trials based on the standard HRF model (<i>6sec-model</i>). (<b>B</b>) The same contrast derived from the alternative <i>4.5sec-model</i> (i.e., optimized for the SC) revealed robust saccade-related activity within both the left and right SC. (<b>C</b>) The direct comparison between centrifugal and centripetal saccades revealed higher activity within the SC (<i>4.5sec-model</i>) as well as a stronger prefrontal deactivation for the former (<i>6sec-model</i>). Activations are displayed on the averaged T1-weighted image. Display cut off: T>2.5, extent threshold k>15.</p

Regions exhibiting differential activations in the direct comparison between centrifugal and centripetal saccades.

<p>L: left hemisphere; R: right hemisphere.</p><p>MNI: Montreal Neurological Institute.</p><p>T-value: local maxima thresholded at p = .005, extent threshold k = 15.</p