Publications associées à Axone géant

Axial and radial axonal diffusivities and radii from single encoding strongly diffusion-weighted MRI

Erick Jorge Canales Rodriguez, Marco Pizzolato, Tim Bjørn Dyrby

We enable the estimation of the per-axon axial diffusivity from single encoding, strongly diffusion-weighted, pulsed gradient spin echo data. Additionally, we improve the estimation of the per-axon radial diffusivity compared to estimates based on spherica ...

ELSEVIER2023

Does powder averaging remove dispersion bias in diffusion MRI diameter estimates within real 3D axonal architectures?

Marco Pizzolato, Tim Bjørn Dyrby

Noninvasive estimation of axon diameter with diffusion MRI holds the potential to investigate the dynamic properties of the brain network and pathology of neurodegenerative diseases. Recent studies use powder averaging to account for complex white matter a ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

Bundle-Specific Axon Diameter Index as a New Contrast to Differentiate White Matter Tracts

Jean-Philippe Thiran, David Paul Roger Romascano, Gabriel Girard, Alessandro Daducci, Cristina Granziera, Muhamed Barakovic, Maxime Descoteaux, Giorgio Innocenti

In the central nervous system of primates, several pathways are characterized by different spectra of axon diameters. In vivo methods, based on diffusion-weighted magnetic resonance imaging, can provide axon diameter index estimates non-invasively. However ...

2021

MorphoSONIC: A morphologically structured intramembrane cavitation model reveals fiber-specific neuromodulation by ultrasound

Silvestro Micera, Esra Neufeld, Elena Vicari, Théo Lemaire

Low-Intensity Focused Ultrasound Stimulation (LIFUS) holds promise for the remote modulation of neural activity, but an incomplete mechanistic characterization hinders its clinical maturation. Here we developed a computational framework to model intramembr ...

CELL PRESS2021

A modeling framework to understand and optimize ultrasound neuromodulation

Théo Lemaire

Over the last decade, Low Intensity Focused Ultrasound Stimulation (LIFUS) has emerged as an attractive technology to modulate the activity of deep neural targets without invasive procedures. However, the underlying mechanisms by which ultrasonic waves can ...

EPFL2021

Axon morphology is modulated by the local environment and impacts the noninvasive investigation of its structure-function relationship

Jean-Philippe Thiran, Jonathan Rafael Patino Lopez, Tim Bjørn Dyrby

Axonal conduction velocity, which ensures efficient function of the brain network, is related to axon diameter. Noninvasive, in vivo axon diameter estimates can be made with diffusion magnetic resonance imaging, but the technique requires three-dimensional ...

National Academy of Sciences2020

DWI Simulation-Assisted Machine Learning Models for Microstructure Estimation

Jean-Philippe Thiran, Erick Jorge Canales Rodriguez, Gabriel Girard, Jonathan Rafael Patino Lopez, Thomas Yu, Muhamed Barakovic, Marco Pizzolato

Diffusion MRI (DW-MRI) allows for the detailed exploration of the brain white matter microstructure, with applications in both research and the clinic. However, state-of-the-art methods for microstructure estimation suffer from known limitations, such as t ...

Springer Nature2020

The Target of Exuberant Projections in Development

Giorgio Innocenti

In addition to neuronal death and elimination of synapses, the production of transient, exuberant axons, and axonal branches is a general phenomenon in development across species and systems. To understand what drives the decision of which axons are mainta ...

2020

Diversity of Cortico-descending Projections: Histological and Diffusion MRI Characterization in the Monkey

Jean-Philippe Thiran, Graham Knott, Maxime Descoteaux, Giorgio Innocenti, Tim Bjørn Dyrby

The axonal composition of cortical projections originating in premotor, supplementary motor (SMA), primary motor (a4), somatosensory and parietal areas and descending towards the brain stem and spinal cord was characterized in the monkey with histological ...

OXFORD UNIV PRESS INC2019

Towards quantitative brain connectomics: microstructure informed tractography via convex optimization

Muhamed Barakovic

Tractography is the only non-invasive technique which is used to reconstruct the white mat- ter structural connectivity of the human brain. It relies on a specific Magnetic Resonance Imaging (MRI) acquisition, called diffusion MRI, which is sensitive to th ...

EPFL2019

Towards non-parametric reconstruction of axon diameter distributions using diffusion MRI and regularized discrete linear modeling

David Paul Roger Romascano

The distribution of axon diameters (ADD) is an important white matter feature: it influences action potential speed, it has been shown to evolve during development, and also to be affected during pathological processes. Diffusion Magnetic Resonance Imaging ...

EPFL2019

In vivo diffusion magnetic resonance imaging of the white matter microstructure from dictionaries generated by Monte Carlo simulations: development and validation

Gaëtan Olivier D Rensonnet

Non-invasive virtual histology of white matter tissues is the ultimate promise of diffusion-weighted MRI (DW-MRI). This hope is fueled by the exquisite sensitivity of DW-MRI to micrometer-scale displacement of diffusing water molecules, averaged over a who ...

EPFL2019

Assessing feasibility and reproducibility of a bundle-specific framework on in vivo axon diameter estimates at 300mT/m

Jean-Philippe Thiran, Gabriel Girard, David Paul Roger Romascano, Jonathan Rafael Patino Lopez, Alessandro Daducci, Muhamed Barakovic, Giorgio Innocenti, Maxime Descoteaux

In vivo quantitative estimation of axon diameter in the white matter could bring new tools to study the structural and functional architecture of the brain. Recently, the feasibility of axon diameter estimation with diffusion-weighted MRI (DW-MRI) has been ...

2018

Validation strategies for the interpretation of microstructure imaging using diffusion MRI

Giorgio Innocenti, Tim Bjørn Dyrby

Extracting microanatomical information beyond the image resolution of MRI would provide valuable tools for diagnostics and neuroscientific research. A number of mathematical models already suggest microstructural interpretations of diffusion MRI (dMRI) dat ...

2018

The Crossed Projection to the Striatum in Two Species of Monkey and in Humans: Behavioral and Evolutionary Significance

Giorgio Innocenti, Tim Bjørn Dyrby

The corpus callosum establishes the anatomical continuity between the 2 hemispheres and coordinates their activity. Using histological tracing, single axon reconstructions, and diffusion tractography, we describe a callosal projection to n caudatus and put ...

Oxford University Press2017

Cortical neurons gradually attain a post-mitotic state

Johannes Gräff

Once generated, neurons are thought to permanently exit the cell cycle and become irreversibly differentiated. However, neither the precise point at which this post-mitotic state is attained nor the extent of its irreversibility is clearly defined. Here we ...

Inst Biochemistry & Cell Biology2016

Multi-Modal Optical Imaging of the Cerebellum in Animals

Graham Knott, Ludovico Silvestri

Thanks to their flexibility, optical techniques could be the key to explore anatomy, plasticity, and functionality of the cerebellum. As an example, an in vivo analysis of the dynamic remodeling of cerebellar axons by nonlinear microscopy can provide funda ...

Springer2016

Accelerated Microstructure Imaging via Convex Optimization (AMICO) from diffusion MRI data

Jean-Philippe Thiran, Alessandro Daducci, Erick Jorge Canales Rodriguez, Tim Bjørn Dyrby, Hui Zhang

Microstructure imaging from diffusion magnetic resonance (MR) data represents an invaluable tool to study non-invasively the morphology of tissues and to provide a biological insight into their microstructural organization. In recent years, a variety of bi ...

Elsevier2015

Accurate and Fast Simulation of Channel Noise in Conductance-Based Model Neurons by Diffusion Approximation

Michele Giugliano

Stochastic channel gating is the major source of intrinsic neuronal noise whose functional consequences at the microcircuit- and network-levels have been only partly explored. A systematic study of this channel noise in large ensembles of biophysically det ...

2011

Evolution amplified processing with temporally dispersed slow neuronal connectivity in primates

Hassan Ghaziri, Giorgio Innocenti

The corpus callosum (CC) provides the main route of communication between the 2 hemispheres of the brain. In monkeys, chimpanzees, and humans, callosal axons of distinct size interconnect functionally different cortical areas. Thinner axons in the genu and ...

National Academy of Sciences2009