scholarly journals Three-dimensional synaptic organization of the human hippocampal CA1 field

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Marta Montero-Crespo ◽  
Marta Dominguez-Alvaro ◽  
Patricia Rondon-Carrillo ◽  
Lidia Alonso-Nanclares ◽  
Javier DeFelipe ◽  
...  
Keyword(s):  
Human Brain ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Reconstruction Method ◽  
Synaptic Organization ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
Hippocampal Ca1 Field ◽  
Cortical Inputs

The hippocampal CA1 field integrates a wide variety of subcortical and cortical inputs, but its synaptic organization in humans is still unknown due to the difficulties involved studying the human brain via electron microscope techniques. However, we have shown that the 3D reconstruction method using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) can be applied to study in detail the synaptic organization of the human brain obtained from autopsies, yielding excellent results. Using this technology, 24,752 synapses were fully reconstructed in CA1, revealing that most of them were excitatory, targeting dendritic spines and displaying a macular shape, regardless of the layer examined. However, remarkable differences were observed between layers. These data constitute the first extensive description of the synaptic organization of the neuropil of the human CA1 region.

scholarly journals Three-dimensional synaptic organization of the human hippocampal CA1 field

2020 ◽  
Author(s):  
Marta Montero-Crespo ◽  
Marta Domínguez-Álvaro ◽  
Patricia Rondón-Carrillo ◽  
Lidia Alonso-Nanclares ◽  
Javier DeFelipe ◽  
...  
Keyword(s):  
Human Brain ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Reconstruction Method ◽  
Synaptic Organization ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
Hippocampal Ca1 Field ◽  
Cortical Inputs

AbstractThe hippocampal CA1 field integrates a wide variety of subcortical and cortical inputs, but its synaptic organization in humans is still unknown due to the difficulties involved studying the human brain via electron microscope techniques. However, we have shown that the 3D reconstruction method using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) can be applied to study in detail the synaptic organization of the human brain obtained from autopsies, yielding excellent results. Using this technology, 24,752 synapses were fully reconstructed in CA1, revealing that most of them were excitatory, targeting dendritic spines and displaying a macular shape, regardless of the layer examined. However, remarkable differences were observed between layers. These data constitute the first extensive description of the synaptic organization of the neuropil of the human CA1 region.

scholarly journals Author response: Three-dimensional synaptic organization of the human hippocampal CA1 field

2020 ◽  
Author(s):  
Marta Montero-Crespo ◽  
Marta Dominguez-Alvaro ◽  
Patricia Rondon-Carrillo ◽  
Lidia Alonso-Nanclares ◽  
Javier DeFelipe ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Author Response ◽  
Synaptic Organization ◽  
Hippocampal Ca1 ◽  
Hippocampal Ca1 Field

scholarly journals Three-dimensional synaptic organization of layer III of the human temporal neocortex

2021 ◽  
Author(s):  
Nicolás Cano-Astorga ◽  
Javier DeFelipe ◽  
Lidia Alonso-Nanclares
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Functional Organization ◽  
Ion Beam ◽  
Three Dimensional ◽  
Cortical Layer ◽  
Cortical Region ◽  
Synaptic Organization ◽  
Synaptic Density ◽  
Temporal Neocortex

AbstractIn the present study we have used Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) to perform a study of the synaptic organization of layer III of Brodmann’s area 21 in human. We analyzed the synaptic density, 3D spatial distribution, and type (excitatory/inhibitory), as well as the shape and size of each synaptic junction of 4945 synapses that were fully reconstructed in 3D. Moreover, the postsynaptic targets of 1888 synapses were determined. We also compared several electron microscopy methods and analysis tools to estimate the synaptic density in the same brain tissue. We have shown that FIB/SEM is much more reliable and robust than the majority of the other commonly used EM techniques. The present work constitutes a detailed description of the synaptic organization of cortical layer III. Further studies on the rest of the cortical layers are necessary to better understand the functional organization of this temporal cortical region.

scholarly journals 3D Ultrastructural Study of Synapses in the Human Entorhinal Cortex

2020 ◽  
Vol 31 (1) ◽  
pp. 410-425 ◽  
Author(s):  
M Domínguez-Álvaro ◽  
M Montero-Crespo ◽  
L Blazquez-Llorca ◽  
J DeFelipe ◽  
L Alonso-Nanclares
Keyword(s):  
Entorhinal Cortex ◽  
Focused Ion Beam ◽  
Functional Organization ◽  
Structural Parameters ◽  
Ion Beam ◽  
Three Dimensional ◽  
Ultrastructural Level ◽  
3D Analysis ◽  
Synaptic Organization ◽  
Health And Disease

Abstract The entorhinal cortex (EC) is a brain region that has been shown to be essential for memory functions and spatial navigation. However, detailed three-dimensional (3D) synaptic morphology analysis and identification of postsynaptic targets at the ultrastructural level have not been performed before in the human EC. In the present study, we used Focused Ion Beam/Scanning Electron Microscopy to perform a 3D analysis of the synapses in the neuropil of medial EC in layers II and III from human brain autopsies. Specifically, we studied synaptic structural parameters of 3561 synapses, which were fully reconstructed in 3D. We analyzed the synaptic density, 3D spatial distribution, and type (excitatory and inhibitory), as well as the shape and size of each synaptic junction. Moreover, the postsynaptic targets of synapses could be clearly determined. The present work constitutes a detailed description of the synaptic organization of the human EC, which is a necessary step to better understand the functional organization of this region in both health and disease.

scholarly journals 3D Synaptic Organization of the Rat CA1 and Alterations Induced by Cocaine Self-Administration

2020 ◽  
Author(s):  
L Blazquez-Llorca ◽  
M Miguéns ◽  
M Montero-Crespo ◽  
A Selvas ◽  
J Gonzalez-Soriano ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Cocaine Addiction ◽  
Stratum Radiatum ◽  
Inhibitory Synapses ◽  
Synaptic Organization ◽  
Self Administration ◽  
Synaptic Density ◽  
Brain Circuit

Abstract The hippocampus plays a key role in contextual conditioning and has been proposed as an important component of the cocaine addiction brain circuit. To gain knowledge about cocaine-induced alterations in this circuit, we used focused ion beam milling/scanning electron microscopy to reveal and quantify the three-dimensional synaptic organization of the neuropil of the stratum radiatum of the rat CA1, under normal circumstances and after cocaine-self administration (SA). Most synapses are asymmetric (excitatory), macular-shaped, and in contact with dendritic spine heads. After cocaine-SA, the size and the complexity of the shape of both asymmetric and symmetric (inhibitory) synapses increased but no changes were observed in the synaptic density. This work constitutes the first detailed report on the 3D synaptic organization in the stratum radiatum of the CA1 field of cocaine-SA rats. Our data contribute to the elucidation of the normal and altered synaptic organization of the hippocampus, which is crucial for better understanding the neurobiological mechanisms underlying cocaine addiction.

3D Observation of Elemental Distribution of Si-Device using a Dedicated FIB/STEM System

2005 ◽  
Author(s):  
T. Yaguchi ◽  
M. Konno ◽  
T. Kamino ◽  
M. Ogasawara ◽  
K. Kaji ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Elemental Distribution ◽  
Multivariate Statistical ◽  
X Ray ◽  
Sample Rotation ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Elemental Maps

Abstract A technique for preparation of a pillar shaped sample and its multi-directional observation of the sample using a focused ion beam (FIB) / scanning transmission electron microscopy (STEM) system has been developed. The system employs an FIB/STEM compatible sample rotation holder with a specially designed rotation mechanism, which allows the sample to be rotated 360 degrees [1-3]. This technique was used for the three dimensional (3D) elemental mapping of a contact plug of a Si device in 90 nm technology. A specimen containing a contact plug was shaped to a pillar sample with a cross section of 200 nm x 200 nm and a 5 um length. Elemental analysis was performed with a 200 kV HD-2300 STEM equipped with the EDAX genesis Energy dispersive X-ray spectroscopy (EDX) system. Spectrum imaging combined with multivariate statistical analysis (MSA) [4, 5] was used to enhance the weak X-ray signals of the doped area, which contain a low concentration of As-K. The distributions of elements, especially the dopant As, were successfully enhanced by MSA. The elemental maps were .. reconstructed from the maps.

scholarly journals Investigation of the selective color-changing mechanism of Dynastes tityus beetle (Coleoptera: Scarabaeidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Color Change ◽  
Incidence Angle ◽  
Ion Beam ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Photonic Materials ◽  
Local Color ◽  
Water Contact ◽  
Color Changes

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.

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