The Effect of Visual Stimulation on GABA and Macromolecule Levels in the Human Brain in vivo

BIOPHYSICS ◽  
2020 ◽  
Vol 65 (1) ◽  
pp. 51-57
Author(s):  
A. Yakovlev ◽  
A. Manzhurtsev ◽  
P. Menshchikov ◽  
M. Ublinskiy ◽  
O. Bozhko ◽  
...  
Keyword(s):  
Human Brain ◽  
Visual Stimulation

scholarly journals Human brain glycogen content and metabolism: implications on its role in brain energy metabolism

2007 ◽  
Vol 292 (3) ◽  
pp. E946-E951 ◽  
Author(s):  
Gülin Öz ◽  
Elizabeth R. Seaquist ◽  
Anjali Kumar ◽  
Amy B. Criego ◽  
Luke E. Benedict ◽  
...  
Keyword(s):  
Human Brain ◽  
Glycogen Content ◽  
Visual Stimulation ◽  
Occipital Lobe ◽  
Glycogen Metabolism ◽  
Adult Brain ◽  
Brain Glycogen ◽  
Free Glucose ◽  
Time Courses

The adult brain relies on glucose for its energy needs and stores it in the form of glycogen, primarily in astrocytes. Animal and culture studies indicate that brain glycogen may support neuronal function when the glucose supply from the blood is inadequate and/or during neuronal activation. However, the concentration of glycogen and rates of its metabolism in the human brain are unknown. We used in vivo localized 13C-NMR spectroscopy to measure glycogen content and turnover in the human brain. Nine healthy volunteers received intravenous infusions of [1-13C]glucose for durations ranging from 6 to 50 h, and brain glycogen labeling and washout were measured in the occipital lobe for up to 84 h. The labeling kinetics suggest that turnover is the main mechanism of label incorporation into brain glycogen. Upon fitting a model of glycogen metabolism to the time courses of newly synthesized glycogen, human brain glycogen content was estimated at ∼3.5 μmol/g, i.e., three- to fourfold higher than free glucose at euglycemia. Turnover of bulk brain glycogen occurred at a rate of 0.16 μmol·g−1·h−1, implying that complete turnover requires 3–5 days. Twenty minutes of visual stimulation ( n = 5) did not result in detectable glycogen utilization in the visual cortex, as judged from similar [13C]glycogen levels before and after stimulation. We conclude that the brain stores a substantial amount of glycogen relative to free glucose and metabolizes this store very slowly under normal physiology.

In Vivo 1H MR Spectroscopic Imaging of Human Brain

1994 ◽  
Vol 31 (2) ◽  
pp. 185
Author(s):  
Yong Whee Bahk ◽  
Kyung Sub Shinn ◽  
Tae Suk Suh ◽  
Bo Young Choe ◽  
Kyo Ho Choi
Keyword(s):  
Human Brain ◽  
Spectroscopic Imaging ◽  
Mr Spectroscopic Imaging

scholarly journals A deep convolutional visual encoding model of neuronal responses in the LGN

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Eslam Mounier ◽  
Bassem Abdullah ◽  
Hani Mahdi ◽  
Seif Eldawlatly
Keyword(s):  
Firing Rate ◽  
Visual Information ◽  
Visual Stimulation ◽  
Neuronal Population ◽  
Neuronal Firing ◽  
Electrode Arrays ◽  
Deep Convolutional Neural Networks ◽  
Firing Rates ◽  
Spatiotemporal Representation

AbstractThe Lateral Geniculate Nucleus (LGN) represents one of the major processing sites along the visual pathway. Despite its crucial role in processing visual information and its utility as one target for recently developed visual prostheses, it is much less studied compared to the retina and the visual cortex. In this paper, we introduce a deep learning encoder to predict LGN neuronal firing in response to different visual stimulation patterns. The encoder comprises a deep Convolutional Neural Network (CNN) that incorporates visual stimulus spatiotemporal representation in addition to LGN neuronal firing history to predict the response of LGN neurons. Extracellular activity was recorded in vivo using multi-electrode arrays from single units in the LGN in 12 anesthetized rats with a total neuronal population of 150 units. Neural activity was recorded in response to single-pixel, checkerboard and geometrical shapes visual stimulation patterns. Extracted firing rates and the corresponding stimulation patterns were used to train the model. The performance of the model was assessed using different testing data sets and different firing rate windows. An overall mean correlation coefficient between the actual and the predicted firing rates of 0.57 and 0.7 was achieved for the 10 ms and the 50 ms firing rate windows, respectively. Results demonstrate that the model is robust to variability in the spatiotemporal properties of the recorded neurons outperforming other examined models including the state-of-the-art Generalized Linear Model (GLM). The results indicate the potential of deep convolutional neural networks as viable models of LGN firing.

scholarly journals Diffusion MRI microstructure models with in vivo human brain Connectome data: results from a multi-group comparison

2017 ◽  
Vol 30 (9) ◽  
pp. e3734 ◽  
Author(s):  
Uran Ferizi ◽  
Benoit Scherrer ◽  
Torben Schneider ◽  
Mohammad Alipoor ◽  
Odin Eufracio ◽  
...  
Keyword(s):  
Human Brain ◽  
Diffusion Mri ◽  
Group Comparison ◽  
Brain Connectome

scholarly journals O-012 Evidence of arterial collapse in a human brain model and in-vivo with aspiration thrombectomy

2021 ◽  
Author(s):  
Y Liu ◽  
D Gebrezgiabhier ◽  
J Arturo Larco ◽  
S Madhani ◽  
A Shahid ◽  
...  
Keyword(s):  
Human Brain ◽  
Aspiration Thrombectomy

scholarly journals Role of SHH in Patterning Human Pluripotent Cells towards Ventral Forebrain Fates

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 914
Author(s):  
Melanie V. Brady ◽  
Flora M. Vaccarino
Keyword(s):  
Stem Cell ◽  
Human Brain ◽  
Human Development ◽  
Disease Modeling ◽  
Model Systems ◽  
Advantages And Disadvantages ◽  
Technical Ability ◽  
Cellular Phenotypes

The complexities of human neurodevelopment have historically been challenging to decipher but continue to be of great interest in the contexts of healthy neurobiology and disease. The classic animal models and monolayer in vitro systems have limited the types of questions scientists can strive to answer in addition to the technical ability to answer them. However, the tridimensional human stem cell-derived organoid system provides the unique opportunity to model human development and mimic the diverse cellular composition of human organs. This strategy is adaptable and malleable, and these neural organoids possess the morphogenic sensitivity to be patterned in various ways to generate the different regions of the human brain. Furthermore, recapitulating human development provides a platform for disease modeling. One master regulator of human neurodevelopment in many regions of the human brain is sonic hedgehog (SHH), whose expression gradient and pathway activation are responsible for conferring ventral identity and shaping cellular phenotypes throughout the neural axis. This review first discusses the benefits, challenges, and limitations of using organoids for studying human neurodevelopment and disease, comparing advantages and disadvantages with other in vivo and in vitro model systems. Next, we explore the range of control that SHH exhibits on human neurodevelopment, and the application of SHH to various stem cell methodologies, including organoids, to expand our understanding of human development and disease. We outline how this strategy will eventually bring us much closer to uncovering the intricacies of human neurodevelopment and biology.

scholarly journals EFFECTS OF POLYMERIC NANOPARTICLE SURFACE PROPERTIES ON INTERACTION WITH BRAIN TUMOR ENVIRONMENT

Nano LIFE ◽  
2013 ◽  
Vol 03 (04) ◽  
pp. 1343003 ◽  
Author(s):  
BRANDON MATTIX ◽  
THOMAS MOORE ◽  
OLGA UVAROV ◽  
SAMUEL POLLARD ◽  
LAUREN O'DONNELL ◽  
...  
Keyword(s):  
Human Brain ◽  
Surface Charge ◽  
Cellular Uptake ◽  
Drug Clearance ◽  
Cellular Interaction ◽  
Normal Tissues ◽  
Poly Ethylene ◽  
Uptake Studies ◽  
Effect Of Surface

Current chemotherapy treatments are limited by poor drug solubility, rapid drug clearance and systemic side effects. Additionally, drug penetration into solid tumors is limited by physical diffusion barriers [e.g., extracellular matrix (ECM)]. Nanoparticle (NP) blood circulation half-life, biodistribution and ability to cross extracellular and cellular barriers will be dictated by NP composition, size, shape and surface functionality. Here, we investigated the effect of surface charge of poly(lactide)-poly(ethylene glycol) NPs on mediating cellular interaction. Polymeric NPs of equal sizes were used that had two different surface functionalities: negatively charged carboxyl ( COOH ) and neutral charged methoxy ( OCH 3). Cellular uptake studies showed significantly higher uptake in human brain cancer cells compared to noncancerous human brain cells, and negatively charged COOH NPs were uptaken more than neutral OCH 3 NPs in 2D culture. NPs were also able to load and control the release of paclitaxel (PTX) over 19 days. Toxicity studies in U-87 glioblastoma cells showed that PTX-loaded NPs were effective drug delivery vehicles. Effect of surface charge on NP interaction with the ECM was investigated using collagen in a 3D cellular uptake model, as collagen content varies with the type of cancer and the stage of the disease compared to normal tissues. Results demonstrated that NPs can effectively diffuse across an ECM barrier and into cells, but NP mobility is dictated by surface charge. In vivo biodistribution of OCH 3 NPs in intracranial tumor xenografts showed that NPs more easily accumulated in tumors with less collagen. These results indicate that a robust understanding of NP interaction with various tumor environments can lead to more effective patient-tailored therapies.

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