Retinotopic Localization of Cortical Thickness Changes

<p>Flattened maps of the right occipital cortex, gyri, and sulci are indicated as light and dark gray. The borders of retinotopic areas are indicated in white (horizontal meridians, solid lines; upper vertical meridians, dotted lines; lower vertical meridians, dashed lines). The image on the left is taken from our previous data [<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0030402#pmed-0030402-b029" target="_blank">29</a>] and shows the progression of CSD during a visual aura, starting in area V3A, in a single participant. The image on the right shows the average map of the mean thickness difference of 24 migraineurs compared with 15 matched controls, projected on the same brain, with the superimposed retinotopy for one participant. A clear correspondence can be seen between the area of CSD origin in V3A in the left image and cortical thickness difference in the right image. In addition, areas of thickening can be observed in visual area MT+.</p

Cortical Thickness Is Increased in Motion-Processing Areas in Migraineurs

<p>Values are presented in mean millimeters (SD). V3A: MWA, 2.00 (0.09); MWoA, 2.06 (0.19); HCs, 1.86 (0.08). MT+: MWA, 2.11 (0.21); MWoA, 2.10 (0.88); HCs, 1.87 (0.17). Asterisks represent <i>p</i>-value summary * <i>p</i> < 0.05; ** <i>p</i> < 0.01</p

DataSheet1.docx

<p>Recent tract-based analyses provided evidence for the exploitability of 3D-SHORE microstructural descriptors derived from diffusion MRI (dMRI) in revealing white matter (WM) plasticity. In this work, we focused on the main open issues left: (1) the comparative analysis with respect to classical tensor-derived indices, i.e., Fractional Anisotropy (FA) and Mean Diffusivity (MD); and (2) the ability to detect plasticity processes in gray matter (GM). Although signal modeling in GM is still largely unexplored, we investigated their sensibility to stroke-induced microstructural modifications occurring in the contralateral hemisphere. A more complete picture could provide hints for investigating the interplay of GM and WM modulations. Ten stroke patients and ten age/gender-matched healthy controls were enrolled in the study and underwent diffusion spectrum imaging (DSI). Acquisitions at three and two time points (tp) were performed on patients and controls, respectively. For all subjects and acquisitions, FA and MD were computed along with 3D-SHORE-based indices [Generalized Fractional Anisotropy (GFA), Propagator Anisotropy (PA), Return To the Axis Probability (RTAP), Return To the Plane Probability (RTPP), and Mean Square Displacement (MSD)]. Tract-based analysis involving the cortical, subcortical and transcallosal motor networks and region-based analysis in GM were successively performed, focusing on the contralateral hemisphere to the stroke. Reproducibility of all the indices on both WM and GM was quantitatively proved on controls. For tract-based, longitudinal group analyses revealed the highest significant differences across the subcortical and transcallosal networks for all the indices. The optimal regression model for predicting the clinical motor outcome at tp3 included GFA, PA, RTPP, and MSD in the subcortical network in combination with the main clinical information at baseline. Region-based analysis in the contralateral GM highlighted the ability of anisotropy indices in discriminating between groups mainly at tp1, while diffusivity indices appeared to be altered at tp2. 3D-SHORE indices proved to be suitable in probing plasticity in both WM and GM, further confirming their viability as a novel family of biomarkers in ischemic stroke in WM and revealing their potential exploitability in GM. Their combination with tensor-derived indices can provide more detailed insights of the different tissue modulations related to stroke pathology.</p

Fractional Anisotropy Differences in Migraineurs Versus Healthy Controls

<p>Coronal (A) and sagittal (B) sections show the areas exhibiting statistically significant lower FA values in migraineurs compared to HCs. Significant differences can be seen in the WM underlying MT+ and V3A areas (A), in the superior colliculus (SC) (B), and in the left LGN (C).</p

Olivary-cerebellar cortex connections and olivary-dentate-olivary loop.

<p>A) Sagittal tractography view, in a DWI image background on the left, showing the connections between (i) the Inferior olivary nucleus (green region of interest -ROI) and the cerebellar cortex (light bright green fiber trajectories) and (ii) the Inferior olivary nucleus and the Dentate nucleus (dark green fiber trajectories). The ROI in the Inferior olive is shown in the sagittal, coronal, and axial planes in the images at bottom (from left to right). B), C) and D) Axial tractography view, in a DWI background, showing: B) the connections between (i) the Inferior olivary nucleus (green ROI) and the dentate nucleus (DN) through Dentate nucleus climbing fibers (DNCF) and (ii) the connections between the inferior olivary nucleus (green ROI) and the cortex through cortical climbing fibers (CCF); C) the intersection between the CCF and parallel fibers (PF) from the granule cell axons. D) PF in the cerebellar cortex. E) and F) Tractography magnification of an axial view of the cerebellar cortex, in DWI background. PF and on the left, PF intersecting CCF. G), H), I) 3D tractography view, in a DWI background, showing: G) some PF traversing the cerebellar cortex. H) PF crossing CF that are oriented perpendicular to them. I) Higher magnification of H).</p

Dentate nucleus connections.

<p>A) Sagittal view and B) sagittal and axial 3D view of the Dentate nucleus (DN - see yellow ROI) in a b0 background image. We show: (i) a subset of connections between DN and the cerebellar cortex (lateral hemisphere) and (ii) fibers identified by the ROI in the DN travelling in the MCP and the SCP. C) 3D localization of the Dentate Nucleus (yellow ROI) in a b0 background image in sagittal, coronal, and axial views (from left to right).</p

Interpositus and Fastigial nuclei connections.

<p>A) Sagittal view of the region containing the Globose and Emboliform nuclei (interpositus nucleus (IN) yellow ROI), in a b0 background image. We show (i) the connections between the IN and the cerebellar cortex (intermediate cortex) and (ii) the fibers that link these deep cerebellar nuclei with the SCP. B) 3D localization of the location of the Globose and Emboliform nuclei (yellow ROI) in a b0 background image in the sagittal, coronal, and axial planes, from left to right. C) Sagittal view of the Fastigial nucleus (FN) (see orange ROI), in a b0 background image. We show (i) the connections between the FN and the cerebellar cortex (vermis) and (ii) the fibers that link the FN with the SCP and ICP D) 3D localization of the FN (see orange ROI) in a b0 background in bottom figures in the sagittal, coronal, and axial planes, from left to right.</p

The three cerebellar peduncles.

<p>Sagittal b0 image showing the superior (SCP- see purple ROI) and Inferior cerebellar peduncles (ICP – see yellow ROI) crossing in the cerebellar white matter core. From the yellow ROI in the brainstem, a pathway connecting to the diencephalon is also tracked B) Sagittal b0 image showing the middle cerebellar peduncle (MCP – see red ROI & white arrow). C) Sagittal view, no background showing the fiber-crossing region (FC) between the inferior and the superior cerebellar peduncles (white arrows) at higher magnification. D) Coronal b0 image showing the precise location of the ROI used to seed the MCP (red ROI, white arrow).</p

Data_Sheet_1_Brain cortical alterations in COVID-19 patients with neurological symptoms.docx

BackgroundGrowing evidence suggests that the central nervous system is affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), since infected patients suffer from acute and long-term neurological sequelae. Nevertheless, it is currently unknown whether the virus affects the brain cortex. The purpose of this study was to assess the cortical gray matter volume, the cortical thickness, and the cortical surface area in a group of SARS-CoV-2 infected patients with neurological symptoms compared to healthy control subjects. Additionally, we analyzed the cortical features and the association with inflammatory biomarkers in the cerebrospinal fluid (CSF) and plasma.Materials and methodsThirty-three patients were selected from a prospective cross-sectional study cohort during the ongoing pandemic (August 2020–April 2021) at the university hospitals of Basel and Zurich (Switzerland). The group included patients with different neurological symptom severity (Class I: nearly asymptomatic/mild symptoms, II: moderate symptoms, III: severe symptoms). Thirty-three healthy age and sex-matched subjects that underwent the same MRI protocol served as controls. For each anatomical T1w MPRAGE image, regional cortical gray matter volume, thickness, and surface area were computed with FreeSurfer. Using a linear regression model, cortical measures were compared between groups (patients vs. controls; Class I vs. II–III), with age, sex, MRI magnetic field strength, and total intracranial volume/mean thickness/total surface area as covariates. In a subgroup of patients, the association between cortical features and clinical parameters was assessed using partial correlation adjusting for the same covariates. P-values were corrected using a false discovery rate (FDR).ResultsOur findings revealed a lower cortical volume in COVID-19 patients’ orbitofrontal, frontal, and cingulate regions than in controls (p ConclusionOur data suggest that viral-triggered inflammation leads to neurotoxic damage in some cortical areas during the acute phase of a COVID-19 infection in patients with neurological symptoms.</p

Thalamic – and Rubro-cerebellar connections.

<p>A) Sagittal b0 image showing cerebellar connections with thalamus (green). The ROI (yellow) is positioned in the ventro-lateral thalamus, as seen on the left in sagittal, coronal and axial slices, from above to below. Some fiber trajectories connecting the thalamus to the brainstem are also shown (blue fiber tracts). B) The 3D localization of the ROI (red) in the red nucleus is shown at left in the sagittal, coronal and axial slices, from above to below. The sagittal b0 image shows the rubro-cerebellar connections (green). Some fiber trajectories connecting the red nucleus to the brainstem are also identified (blue fiber tracts).</p