Ami Tsuchida

University of Bordeaux

Cerebral small vessel disease (cSVD) is a leading cause of vascular cognitive impairment and dementia. Mounting evidence suggests that early life factors contribute to cSVD. Genetic risk loci for white matter hyperintensities (WMH), the most common MRI‐marker of cSVD in older age, were recently found to show strong associations with white matter mi...

Perivascular space (PVS) burden is an emerging MRI‐marker of cerebral small vessel disease (cSVD), a leading cause of stroke and dementia. Underlying mechanisms of PVS are unknown. PVS are thought to be related to the glymphatic system, involved in brain clearance of molecules such as amyloid beta. We aimed to decipher the genetic underpinnings of...

Perivascular space burden (PVS) is an emerging and possibly the earliest magnetic resonance imaging (MRI)-marker of cerebral small vessel disease (cSVD), a leading cause of stroke and dementia. Its molecular underpinnings are unknown. Genome-wide and whole-exome association studies in 40,095 participants (21 population-based cohorts, 66.3±8.6 years...

Background Subcortical brain structures play a key role in pathological processes of age-related neurodegenerative disorders. Mounting evidence also suggests that early-life factors may have an impact on the development of common late-life neurological diseases, including genetic factors that can influence both brain maturation and neurodegeneratio...

We report on MRi-Share, a multi-modal brain MRI database acquired in a unique sample of 1870 young healthy adults, aged 18–35 years, while undergoing university-level education. MRi-Share contains structural (T1 and FLAIR), diffusion (multispectral), susceptibility-weighted (SWI), and resting-state functional imaging modalities. Here, we described...

The relationship between hippocampal subfield volumetry and verbal list-learning test outcomes have mostly been studied in clinical and elderly populations, and remain controversial. For the first time, we characterized a relationship between verbal list-learning test outcomes and hippocampal subfield volumetry on two large separate datasets of 447...

Human brain white matter undergoes a protracted maturation that continues well into adulthood. Recent advances in diffusion-weighted imaging (DWI) methods allow detailed characterizations of the microstructural architecture of white matter, and they are increasingly utilized to study white matter changes during development and aging. However, relat...

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...

Background and Objectives: Young adults represent an increasingly large proportion of healthy volunteers in brain imaging research, but descriptions of incidental findings (IFs) in this age group are scarce. We aimed to assess the prevalence and severity of IFs on brain MRIs of healthy young research participants aged 18–35 years, and to describe t...

Human brain white matter undergoes a protracted maturation that continues well into adulthood. Recent advances in diffusion-weighted imaging (DWI) methods allow detailed characterizations of the microstructural architecture of white matter, and they are increasingly utilised to study white matter changes during development and ageing. However, rela...

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were...

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...

The frontal lobes have long been implicated in inhibitory control, but a full understanding of the underlying mechanisms remains elusive. The stop-signal task has been widely used to probe instructed response inhibition in cognitive neuroscience. The processes involved have been modelled and related to putative brain substrates. However, there has...

The size of the human head is determined by growth in the first years of life, while the rest of the body typically grows until early adulthood. Such complex developmental processes are regulated by various genes and growth pathways. Rare genetic syndromes have revealed genes that affect head size, but the genetic drivers of variation in head size...

We report on MRi-Share, a multi-modal brain MRI database acquired in a unique sample of 1,870 young healthy adults, aged 18 to 35 years, while undergoing university-level education. MRi-Share contains structural (T1 and FLAIR), diffusion (multispectral), susceptibility weighted (SWI), and resting-state functional imaging modalities. Here, we descri...

Parameters of water diffusion in white matter derived from diffusion-weighted imaging (DWI), such as fractional anisotropy (FA), mean, axial, and radial diffusivity (MD, AD, and RD), and more recently, peak width of skeletonized mean diffusivity (PSMD), have been proposed as potential markers of normal and pathological brain ageing. However, their...

Navigating our complex social world requires effective processing of subtle emotional signals, such as those conveyed by facial expressions. Failure to do so may underlie some of the disabling social-emotional deficits common in a range of neuropsychiatric and neurological conditions. Prefrontal cortex (PFC) has long been implicated in these proces...

Adaptive decision making involves selecting the most valuable option, typically by taking an action. Such choices require value comparisons, but there is debate about whether these comparisons occur at the level of stimuli (goods-based) value, action-based value, or both. One view is that value processes occur in series, with stimulus value informi...

Existing tools for rapid cognitive assessment in HIV-positive individuals with mild cognitive deficits lack sensitivity or do not meet psychometric requirements for tracking changes in cognitive ability over time. Seventy-five nondemented HIV-positive patients were evaluated with the Montreal Cognitive Assessment (MoCA), a brief battery of standard...

Background / Purpose: This study attempts to clarify the precise roles played by right inferior frontal cortex (RIFC) and dorsomedial frontal cortex (DMF) in the performance of tasks requiring motor response inhibition.It has been proposed that these areas are important not for response inhibition per se, but for other aspects of the task, such a...

Damage to the orbitofrontal cortex (OFC) has been linked to impaired reinforcement processing and maladaptive behavior in changing environments across species. Flexible stimulus-outcome learning, canonically captured by reversal learning tasks, has been shown to rely critically on OFC in rats, monkeys, and humans. However, the precise role of OFC i...

Although prefrontal cortex is clearly important in executive function, the specific processes carried out by particular regions within human prefrontal cortex remain a matter of debate. A rapidly growing corpus of functional imaging work now implicates various areas within prefrontal cortex in a wide range of "executive" tasks. Loss-of-function stu...