Intertwining scheme.

<p>Schematic representation of the principle of intertwining of the VSA ring and the PTF ring within each hemisphere, thanks to the major long-range tract fibers.</p

overlap matrix.

<p>(A) Matrix of 30RSN×28BA (Brodmann Area). 20*: BA20+BA38, 41*: BA41+42, 28*: BA28+BA34+BA35+BA36, 32*:BA32+BA24+BA25, 23*:BA23+BA29+BA30+BA31, (B) Matrix of 30RSN×7BAF (Brodmann Area Family), see the details concerning the BAFs and RSNs in the text. Both matrices are reorganized by applying the same Expectation Maximization (EM) algorithm as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Fig. 2C</a>, to reveal the RSNs clusters with a similar topography on the cortical surface. The RSNs are ranked on the vertical axis according to this clustering. BA×RSN matrix clusters: 1 (RSN# 1, 23, 2, 5, 22, 9), 2 (20, 21), 3 (4, 7, 18), 4 (14, 25, 27, 32,17), 5 (24, 13, 29, 28, 30, 11, 19, 31, 26, 16), 6 (3, 15) and 7 (6, 8). matrix clusters: 1 (RSN# 2, 22, 9, 5), 2 (4,7,21), 3 (18), 4 (20), 5 (25, 14, 17, 32), 6 (27, 28, 11, 29, 13, 19, 6, 26, 18, 20, 8 and 24), 7 (3, 15, 30, 16), 8 (31), 9 (23) and 10 (1). Color bars (to the right of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g003" target="_blank">Figures 3A, 3B</a>) indicate: visual (red), somatomotor (orange), auditory (green), left, right and bilateral RSNs (red) and as in Table in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Fig. 2C</a>, RSNs of intermediate region are in (black). Scale bars represent the number of shared voxels.</p

Long distance cortical connections closing the PTF ring.

<p>Comparison of the topography of the two rings (lateral and dorsal views), with superimposed major cortical fiber tracts (see text for details). Mapping of major long-distance fiber tracts on the 3D mask of the PTF ring (Fig. A) and VSA ring (Fig. B). Long-range connections on the VSA ring and the PTF ring, mapped together (Fig. C).</p

Mapping and representativeness of RSNs and similarities in two different populations.

<p>(A) Mapping of the 32 Resting State Networks (RSNs), on the right hemisphere (above) and the left hemisphere (below), on the lateral face (left) and the medial face (right). (B) Representativeness of the 32 RSNs. The color of each bar corresponds to the color of the RSNs network in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g001" target="_blank">Figure 1A</a> and the RSNs are labeled with their representativeness rank. (C) Spatial similarity rate between equivalent RSNs in the Cambridge and Beijing populations.</p

Mapping of VSA and PTF families.

<p>(A) Comparison of clustering results on the 3 matrices , and . All clustering results are obtained with the same method: Mixture Distribution Algorithm. is a cluster of RSNs obtained from matrix (RSNxi), , , where p is the number of clusters. IR: Intermediate Regions are represented by RSN# 1, 23, 27 (B) Mapping of the 2 families which group the RSNs, according to the clustering based on functional specialization (as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Fig. 2</a>) and the clustering based on cortical topography (shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g003" target="_blank">Fig. 3</a>), giving both the same results: VSA family formed by 3 clusters, LR (Left and Right = bilateral) Visual RSNs, in blue; LR Auditory RSNs in green and LR somatomotor RSNs in orange, with similar colors as in Table in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Fig. 2C</a>. PTF family: R (right lateralized) RSNs in dark purple, L (left lateralized) RSNs in light purple and LR (bilateral) RSNs in red, distributed over the parietal, frontal, temporal and cingular regions. (C) The two intertwined rings per hemisphere: the visual, somatomotor and auditory RSNs clusters shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g004" target="_blank">Fig. 4</a> and grouped in the VSA family form the VSA ring, in blue, and the RSNs of the PTF family, distributed over the parietal, temporal, frontal and cingular regions form the PTF ring, in red. The overlap between the two families is shown in purple. The two rings are intertwined as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g007" target="_blank">Fig. 7</a>.</p

RSN×TBN overlap matrix.

<p>(A) RSN×TBN matrix showing overlaps (topographical similarity) between the 32 Resting State Networks (RSN, vertical axis) and the 18 reference Task Based Networks (TBNs, horizontal axis). The RSN are labeled as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g001" target="_blank">Fig. 1</a> and the TBNs are labeled as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone.0067444-Laird1" target="_blank">[14]</a>. The RSNs and TBNs are ranked according to the maximum of their overlaps. (B) RSN×TBN matrix reorganized by applying an Expectation Maximization (EM) algorithm to display the RSN clusters having similar overlaps with the TBNs (see text for details). The RSN×TBN clusters are: 1 (RSN# 2, 5, 22, 9), 2 (20, 7, 18, 21), 3 (4), 4 (14, 25), 5 (32, 17, 27) and 6 (6, 1, 23, 24, 13, 29, 3, 28, 30, 11, 19, 31, 26, 8, 16, 15). The color bars (at the right of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Figure 2B</a>) indicate: visual (blue), somatomotor (orange), auditory (green), left, right and bilateral RSN (red), and RSNs of intermediate region (black). Scale bars represents the nuber of shared voxels. (C) This table shows the correspondence between RSNs and TBNs obtained by the maximal overlap between them, with the main sensory-motor and cognitive functions of the TBNs. The masks, labels and functions of TBNs are taken from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone.0067444-Laird1" target="_blank">[14]</a>. The labels of RSNs correspond to their representativeness in the group of subjects, as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g001" target="_blank">Fig. 1</a>. The colors used for RSNs labels, are the same as color bars in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g002" target="_blank">Fig. 2B</a>.</p

The dual intertwined rings architecture.

<p>(A1) The VSA ring, in blue, forms a continuous cortical ring organized around primary cortices: visual (V), auditory (A) and somatomotor (S) with interspersed bimodal regions: visuo-somatomotor (VS), auditory-somatomotor (SA) and visuo-auditory (VA). (A2) The PTF ring, in red, forms a ring discontinuous over the cortical mantle but closed by major cortical fiber tracts (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g006" target="_blank">Fig. 6</a>), with 3 regions, parietal, temporal and frontal on the lateral (l) aspect of each hemisphere (lP,lT,lF) and 3 regions parietal, temporal and frontal, on the medial (m) aspect (mP,mT,mF). (B) The two rings are intertwined: the PTF ring, in red, is placed in foreground, to show that it is not continuous over the cortical mantle but interrupted by the VSA ring and is closed by major cortical fiber tracts passing below the VSA ring, as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067444#pone-0067444-g006" target="_blank">Fig. 6</a>.</p

Contribution of Corticospinal Tract and Functional Connectivity in Hand Motor Impairment after Stroke

<div><p>Background</p><p>Motor outcome after stroke is associated with reorganisation of cortical networks and corticospinal tract (CST) integrity. However, the relationships between motor severity, CST damage, and functional brain connectivity are not well understood. Here, the main objective was to study the effect of CST damage on the relationship between functional motor network connectivity and hand motor function in two groups of stroke patients: the severely (n=8) and the mildly impaired (n=14).</p> <p>Methods</p><p>Twenty-two carotid stroke patients with motor deficits were studied with magnetic resonance imaging (MRI) at 3 weeks, at 3 and 6 months. Healthy subjects (n=28) were scanned once. The CST injury was assessed by fractional anisotropy values. Functional connectivity was studied from a whole-hand grip task fMRI in a cortical and cerebellar motor network. Functional connectivity indexes were computed between these regions at each time point. The relationship between hand motor strength, ipsilesional CST damage and functional connectivity from the primary motor cortex (M1) was investigated using global and partial correlations.</p> <p>Findings</p><p>In mildly impaired patients, cortico-cortical connectivity was disturbed at three weeks but returned to a normal pattern after 3 months. Cortico-cerebellar connectivity was still decreased at 6 months. In severely impaired patients, the cortico-cortical connectivity tended to return to a normal pattern, but the cortico-cerebellar connectivity was totally abolished during the follow-up. In the entire group of patients, the hand motor strength was correlated to the ipsilesional functional connectivity from M1. Partial correlations revealed that these associations were not anymore significant when the impact of CST damage was removed, except for the ipsilesional M1-contralateral cerebellum connectivity.</p> <p>Conclusion</p><p>Functional brain connectivity changes can be observed, even in severely impaired patients with no recovery. Upper limb function is mainly explained by the CST damage and by the ipsilesional cortico-cerebellar connectivity.</p> </div

Positive and Negative Predictive Values for good outcome as a function of CoRad-rAD values.

<p>The positive predictive values (PPV in green) correspond to the CoRad-rAD values above the threshold (x-axis). The negative predictive values (NPV in red) correspond to the CoRad-rAD values below the threshold. (A) Good outcome is assessed by NIHSS item 5 for upper limb (UL) scores 0–1 at day 7 post-stroke. (B) Very good outcome is assessed by mRS ≤ 1 at 3 months post-stroke. (C) Good outcome is assessed by mRS ≤ 2.</p

Regions-of-Interest for extraction of diffusion parameters.

<p>A preview of the Regions-of-Interest (in red) used in the analysis overlaid on the FMRIB58 fractional anisotropy standard space image. (A) White matter underlying the pre-central gyrus. (B) Corona Radiata. (C) Posterior Limb of Internal Capsule (D) Cerebral Peduncles (E) Genu of the Corpus Callosum.</p