Brain, language, and handedness: a family affair

The left planum temporale is a marker of left hemisphere language specialization. We investigated the effect of individual handedness and familial sinistrality on left planum temporale surface area and found the size is reduced in proportion with the number of left-handed immediate family members and is lowest when one's mother is left-handed. This reduction is independent of an individual's handedness or sex and has no counterpart in the right hemisphere

The Skin-Conductance Component of Error Correction in a Logical Reasoning Task

La Réponse ÉlectroDermale (RED) a été mesurée à deux reprises chez les mêmes sujets qui réalisaient une tâche de logique déductive, d’abord en commettant une erreur de raisonnement et ensuite, après un apprentissage, soit en répondant correctement, soit en persévérant dans l’erreur selon les sujets. La RED s’est accrue entre les deux sessions et était significativement plus importante chez les sujets qui corrigeaient leur erreur initiale de raisonnement que chez les autres, révélant la forte interconnexion entre le raisonnement logique et les indices d’états somatiques impliqués dans l’émotion. Cela corrobore les résultats d’études antérieures d’imagerie cérébrale réalisées dans notre groupe et indiquant que l’accès à la logique déductive dépend du cortex préfrontal ventromédian droit dont on connaît l’implication dans la représentation afférente de la RED et dans l’intégration émotion-cognition.Skin Conductance Responses (SCRs) were measured in a deductive logic task performed twice by the same subjects, first making reasoning errors and then, after training, providing logical responses or making errors again, depending on the subject. SCRs increased between the two sessions and were significantly higher in the subjects who corrected their reasoning errors than in those that did not, showing the strong interplay between logical reasoning and indices of somatic states involved in emotion. This fits well with the results of previous brain imaging studies from our group showing that access to deductive logic depends on a right ventromedial prefrontal area involved in SCRs afferent representation and emotion-cognition integration

Cortical Terminations of the Inferior Fronto-Occipital and Uncinate Fasciculi: Anatomical Stem-Based Virtual Dissection

International audienceWe combined the neuroanatomists' approach of defining a fascicle as all fibers passing through its compact stem with diffusion-weighted tractography to investigate the cortical terminations of two association tracts, the inferior fronto-occipital fasciculus (IFOF) and the uncinate fasciculus (UF), which have recently been implicated in the ventral language circuitry. The aim was to provide a detailed and quantitative description of their terminations in 60 healthy subjects and to do so to apply an anatomical stem-based virtual dissection, mimicking classical post-mortem dissection, to extract with minimal a priori the IFOF and UF from tractography datasets. In both tracts, we consistently observed more extensive termination territories than their conventional definitions, within the middle and superior frontal, superior parietal and angular gyri for the IFOF and the middle frontal gyrus and superior, middle and inferior temporal gyri beyond the temporal pole for the UF. We revealed new insights regarding the internal organization of these tracts by investigating for the first time the frequency, distribution and hemispheric asymmetry of their terminations. Interestingly, we observed a dissociation between the lateral right-lateralized and medial left-lateralized fronto-occipital branches of the IFOF. In the UF, we observed a rightward lateralization of the orbito-frontal and temporal branches. We revealed a more detailed map of the terminations of these fiber pathways that will enable greater specificity for correlating with diseased populations and other behavioral measures. The limitations of the diffusion tensor model in this study are also discussed. We conclude that anatomical stem-based virtual dissection with diffusion tractography is a fruitful method for studying the structural anatomy of the human white matter pathways

Structural brain lesions and restless legs syndrome: a cross-sectional population-based study

Objective: To evaluate the association between white matter lesion (WML) volume, silent infarcts and restless legs syndrome (RLS) in a population-based study of elderly individuals. Design: Cross-sectional study. Setting: Population-based Three-City study. Participants: 1035 individuals from the Dijon, France, centre of the Three-City study who had available information on volume of WMLs from MRIs and who answered questions about the prevalence of RLS. Primary outcome measure Prevalence of RLS. Results: WML volume was measured using an automated tissue segmentation method. Logistic regression was used to evaluate adjusted associations between tertiles of WML volume and RLS and between silent infarcts and RLS. 218 individuals (21.1%) were determined to have RLS. Compared with those in the first tertile of WML volume, individuals in the second tertile (OR=1.09; 95% CI 0.75 to 1.60) or third tertile (OR=1.17; 95% CI 0.79 to 1.74) did not have an increased prevalence of RLS. We also did not observe associations between the volume of deep or periventricular WML and RLS; nor did we observe an association between silent brain infarcts and RLS (OR=0.74; 95% CI 0.40 to 1.39). These findings were not modified by age or gender. Conclusions: Higher volume of WML and the presence of silent infarcts were not associated with an increased prevalence of RLS in this population-based cohort of elderly individuals

Effects of blood pressure lowering on cerebral white matter hyperintensities in patients with stroke: the PROGRESS (Perindopril Protection Against Recurrent Stroke Study) Magnetic Resonance Imaging Substudy.: The PROGRESS MRI Substudy.

International audienceBACKGROUND: The prevalence of white matter hyperintensities (WMHs) detected on cerebral MRI is associated with hypertension, but it is not known whether blood pressure lowering can arrest their progression. We report here the results of an MRI substudy of PROGRESS (Perindopril Protection Against Recurrent Stroke Study), a randomized trial of blood pressure lowering in subjects with cerebrovascular disease. METHODS AND RESULTS: The substudy comprised 192 participants who had a cerebral MRI both at baseline and after a mean follow-up time of 36 months (SD=6.0 months). At the first MRI, WMHs were graded with a visual rating scale from A (no WMH) to D (severe WMH). Participants were assigned to a combination of perindopril plus indapamide (or their placebos; 58%) or to single therapy with perindopril (or placebo). At the time of the second MRI, the blood pressure reduction in the active arm compared with the placebo arm was 11.2 mm Hg for systolic blood pressure and 4.3 mm Hg for diastolic blood pressure. Twenty-four subjects (12.5%) developed new WMHs at follow-up. The risk of new WMH was reduced by 43% (95% CI -7% to 89%) in the active treatment group compared with the placebo group (P=0.17). The mean total volume of new WMHs was significantly reduced in the active treatment group (0.4 mm3 [SE=0.8]) compared with the placebo group (2.0 mm3 [SE=0.7]; P=0.012). This difference was greatest for patients with severe WMH at entry, 0.0 mm3 (SE=0) in the active treatment group versus 7.6 mm3 (SE=1.0) in the placebo group (P<0.0001). CONCLUSIONS: These results indicate that an active blood pressure-lowering regimen stopped or delayed the progression of WMHs in patients with cerebrovascular disease

Multiple indices of diffusion identifies white matter damage in mild cognitive impairment and Alzheimer's disease

The study of multiple indices of diffusion, including axial (DA), radial (DR) and mean diffusion (MD), as well as fractional anisotropy (FA), enables WM damage in Alzheimer's disease (AD) to be assessed in detail. Here, tract-based spatial statistics (TBSS) were performed on scans of 40 healthy elders, 19 non-amnestic MCI (MCIna) subjects, 14 amnestic MCI (MCIa) subjects and 9 AD patients. Significantly higher DA was found in MCIna subjects compared to healthy elders in the right posterior cingulum/precuneus. Significantly higher DA was also found in MCIa subjects compared to healthy elders in the left prefrontal cortex, particularly in the forceps minor and uncinate fasciculus. In the MCIa versus MCIna comparison, significantly higher DA was found in large areas of the left prefrontal cortex. For AD patients, the overlap of FA and DR changes and the overlap of FA and MD changes were seen in temporal, parietal and frontal lobes, as well as the corpus callosum and fornix. Analysis of differences between the AD versus MCIna, and AD versus MCIa contrasts, highlighted regions that are increasingly compromised in more severe disease stages. Microstructural damage independent of gross tissue loss was widespread in later disease stages. Our findings suggest a scheme where WM damage begins in the core memory network of the temporal lobe, cingulum and prefrontal regions, and spreads beyond these regions in later stages. DA and MD indices were most sensitive at detecting early changes in MCIa

Motor function in the elderly: evidence for the reserve hypothesis.

International audienceThe reserve hypothesis accounts for the lack of direct relationship between brain pathology and its clinical manifestations. Research has mostly focused on cognition; our objective is to examine whether the reserve hypothesis applies to motor function. We investigated whether education, a marker of reserve, modifies the association between white matter lesions (WMLs), a marker of vascular brain damage, and maximum walking speed (WS), an objective measure of motor function. We also examined the cross-sectional and longitudinal association between education and WS. Data are from 4,010 participants aged 65-85 years in the longitudinal Three-City-Dijon Study with up to 4 WS measures over 10 years. We examined the interaction between education and WMLs for baseline WS. We studied the association between education and repeated WS measures using linear mixed models, and the role of covariates in explaining the education-WS association. Education was strongly associated with baseline WS; the difference in mean WS between the high and low education groups (0.145 m/s, 95% confidence interval = 0.125-0.165) was equivalent to 7.4 years of age. WMLs were associated with slow WS only in the low education group (p interaction = 0.026). WS declined significantly over time (-0.194 m/s/10 years, 95% confidence interval = -0.206, -0.182), but education did not influence rate of decline. Anthropometric characteristics, parental education, general health, and cognition had the strongest role in explaining the baseline education-WS association. Participants with more education were less susceptible to WMLs' effect on motor function. Higher education was associated with better motor performances but not with motor decline. These results are consistent with the passive reserve hypothesis

3D Segmentation of Perivascular Spaces on T1-Weighted 3 Tesla MR Images With a Convolutional Autoencoder and a U-Shaped Neural Network

We implemented a deep learning (DL) algorithm for the 3-dimensional segmentation of perivascular spaces (PVSs) in deep white matter (DWM) and basal ganglia (BG). This algorithm is based on an autoencoder and a U-shaped network (U-net), and was trained and tested using T1-weighted magnetic resonance imaging (MRI) data from a large database of 1,832 healthy young adults. An important feature of this approach is the ability to learn from relatively sparse data, which gives the present algorithm a major advantage over other DL algorithms. Here, we trained the algorithm with 40 T1-weighted MRI datasets in which all "visible" PVSs were manually annotated by an experienced operator. After learning, performance was assessed using another set of 10 MRI scans from the same database in which PVSs were also traced by the same operator and were checked by consensus with another experienced operator. The Sorensen-Dice coefficients for PVS voxel detection in DWM (resp. BG) were 0.51 (resp. 0.66), and 0.64 (resp. 0.71) for PVS cluster detection (volume threshold of 0.5 within a range of 0 to 1). Dice values above 0.90 could be reached for detecting PVSs larger than 10 mm(3) and 0.95 for PVSs larger than 15 mm(3). We then applied the trained algorithm to the rest of the database (1,782 individuals). The individual PVS load provided by the algorithm showed a high agreement with a semi-quantitative visual rating done by an independent expert rater, both for DWM and for BG. Finally, we applied the trained algorithm to an age-matched sample from another MRI database acquired using a different scanner. We obtained a very similar distribution of PVS load, demonstrating the interoperability of this algorithm.Stopping cognitive decline and dementia by fighting covert cerebral small vessel diseas

Headache, migraine, and structural brain lesions and function: population based Epidemiology of Vascular Ageing-MRI study

Objective To evaluate the association of overall and specific headaches with volume of white matter hyperintensities, brain infarcts, and cognition

Fish Intake and MRI Burden of Cerebrovascular Disease in Older Adults

BACKGROUND AND OBJECTIVE: Fish intake may prevent cerebrovascular disease (CVD), yet the mechanisms are unclear, especially regarding its impact on subclinical damage. Assuming that fish may have pleiotropic effect on cerebrovascular health, we investigated the association of fish intake with global CVD burden based on brain MRI markers. METHODS: This cross-sectional analysis included participants from the Three-City Dijon population-based cohort (aged >/=65 years) without dementia, stroke, or history of hospitalized cardiovascular disease, who underwent brain MRI with automated assessment of white matter hyperintensities, visual detection of covert infarcts, and grading of dilated perivascular spaces. Fish intake was assessed through a frequency questionnaire and the primary outcome measure was defined as the first component of a factor analysis of mixed data applied to MRI markers. The association of fish intake with the CVD burden indicator was studied using linear regressions. RESULTS: In total, 1,623 participants (mean age, 72.3 years; 63% women) were included. The first component of factor analysis (32.4% of explained variance) was associated with higher levels of all three MRI markers. Higher fish intake was associated with lower CVD burden. In a model adjusted for total intracranial volume, compared to participants consuming fish /=4 times per week had a beta = -0.19 (95% CI, -0.37; -0.01) and beta = -0.30 (-0.57; -0.03) lower indicator of CVD burden, respectively (P trend /=75 years. For comparison, in the younger age group, consuming fish 2-3 times a week was roughly equivalent (in opposite direction) to the effect of hypertension. DISCUSSION: In this large population-based study, higher frequency of fish intake was associated with lower CVD burden, especially among participants younger than 75 years, suggesting a beneficial effect on brain vascular health before manifestation of overt brain disease. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in individuals without stroke or dementia, higher fish intake is associated with lower subclinical CVD at MRI