Cellule amacrine | EPFL Graph Search

Les cellules amacrines sont des interneurones unipolaires, présents dans l'œil des vertébrés, souvent dépourvus d'axone. On les trouve au niveau de la rétine. Les cellules granulaires du bulbe olfactif sont aussi des exemples de cellule amacrine. Elles font partie de la classification histologique des neurones unipolaires. Catégorie:Neurone Catégorie:Anatomie de l'œil

Semi-automatic 3D morphological reconstruction of neurons with densely branching morphology: Application to retinal All amacrine cells imaged with multi -photon excitation microscopy

Bas-Jan Zandt

Background: Accurate reconstruction of the morphology of single neurons is important for morphometric studies and for developing compartmental models. However, manual morphological reconstruction can be extremely time-consuming and error-prone and algorithms for automatic reconstruction can be challenged when applied to neurons with a high density of extensively branching processes. New method: We present a procedure for semi-automatic reconstruction specifically adapted for densely branching neurons such as the All amacrine cell found in mammalian retinas. We used whole-cell recording to fill All amacrine cells in rat retinal slices with fluorescent dyes and acquired digital image stacks with multi-photon excitation microscopy. Our reconstruction algorithm combines elements of existing procedures, with segmentation based on adaptive thresholding and reconstruction based on a minimal spanning tree. We improved this workflow with an algorithm that reconnects neuron segments that are disconnected after adaptive thresholding, using paths extracted from the image stacks with the Fast Marching method. Results: By reducing the likelihood that disconnected segments were incorrectly connected to neighboring segments, our procedure generated excellent morphological reconstructions of All amacrine cells. Comparison with existing methods: Reconstructing an All amacrine cell required about 2 h computing time, compared to 2-4 days for manual reconstruction. To evaluate the performance of our method relative to manual reconstruction, we performed detailed analysis using a measure of tree structure similarity (DIADEM score), the degree of projection area overlap (Dice coefficient), and branch statistics. Conclusions: We expect our procedure to be generally useful for morphological reconstruction of neurons filled with fluorescent dyes. (C) 2017 Elsevier B.V. All rights reserved.

Elsevier2017

Single-cell transcriptional logic of cell-fate specification and axon guidance in early-born retinal neurons

Pierre Raymond Fabre, Gioele La Manno, Marion Leleu

Retinal ganglion cells (RGCs), cone photoreceptors (cones), horizontal cells and amacrine cells are the first classes of neurons produced in the retina. However, an important question is how this diversity of cell states is transcriptionally produced. Here, we profiled 6067 single retinal cells to provide a comprehensive transcriptomic atlas showing the diversity of the early developing mouse retina. RNA velocities unveiled the dynamics of cell cycle coordination of early retinogenesis and define the transcriptional sequences at work during the hierarchical production of early cell-fate specification. We show that RGC maturation follows six waves of gene expression, with older-generated RGCs transcribing increasing amounts of guidance cues for young peripheral RGC axons that express the matching receptors. Spatial transcriptionally deduced features in subpopulations of RGCs allowed us to define novel molecular markers that are spatially restricted. Finally, the isolation of such a spatially restricted population, ipsilateral RGCs, allowed us to identify their molecular identity at the time they execute axon guidance decisions. Together, these data represent a valuable resource shedding light on transcription factor sequences and guidance cue dynamics during mouse retinal development.

2019

Semi-automatic 3D morphological reconstruction of neurons with densely branching morphology: Application to retinal All amacrine cells imaged with multi -photon excitation microscopy

Bas-Jan Zandt

Elsevier2017