scholarly journals Network remodeling induced by transcranial brain stimulation: A computational model of tDCS-triggered cell assembly formation

2018 ◽  
Author(s):  
Han Lu ◽  
Júlia V. Gallinaro ◽  
Stefan Rotter
Keyword(s):  
Recurrent Network ◽  
Inhibitory Neurons ◽  
Brain Diseases ◽  
Cell Assembly ◽  
Excitatory Synapses ◽  
Non Invasive ◽  
Duty Cycles ◽  
Transcranial Brain Stimulation ◽  
A Cell ◽  
The Impact

AbstractTranscranial direct current stimulation (tDCS) is a variant of non-invasive neuromodulation, which promises treatment for brain diseases like major depressive disorder. In experiments, long-lasting aftereffects were observed, suggesting that persistent plastic changes are induced. The mechanism underlying the emergence of lasting aftereffects, however, remains elusive. Here we propose a model, which assumes that tDCS triggers a homeostatic response of the network involving growth and decay of synapses. The cortical tissue exposed to tDCS is conceived as a recurrent network of excitatory and inhibitory neurons, with synapses subject to homeostatically regulated structural plasticity. We systematically tested various aspects of stimulation, including electrode size and montage, as well as stimulation intensity and duration. Our results suggest that transcranial stimulation perturbs the homeostatic equilibrium and leads to a pronounced growth response of the network. The stimulated population eventually eliminates excitatory synapses with the unstimulated population, and new synapses among stimulated neurons are grown to form a cell assembly. Strong focal stimulation tends to enhance the connectivity within new cell assemblies, and repetitive stimulation with well-chosen duty cycles can increase the impact of stimulation even further. One long-term goal of our work is to help optimizing the use of tDCS in clinical applications.

scholarly journals Network remodeling induced by transcranial brain stimulation: A computational model of tDCS-triggered cell assembly formation

2019 ◽  
Vol 3 (4) ◽  
pp. 924-943 ◽  
Author(s):  
Han Lu ◽  
Júlia V. Gallinaro ◽  
Stefan Rotter
Keyword(s):  
Recurrent Network ◽  
Inhibitory Neurons ◽  
Brain Diseases ◽  
Cell Assembly ◽  
Excitatory Synapses ◽  
Duty Cycles ◽  
Transcranial Brain Stimulation ◽  
A Cell ◽  
Noninvasive Neuromodulation ◽  
The Impact

Transcranial direct current stimulation (tDCS) is a variant of noninvasive neuromodulation, which promises treatment for brain diseases like major depressive disorder. In experiments, long-lasting aftereffects were observed, suggesting that persistent plastic changes are induced. The mechanism underlying the emergence of lasting aftereffects, however, remains elusive. Here we propose a model, which assumes that tDCS triggers a homeostatic response of the network involving growth and decay of synapses. The cortical tissue exposed to tDCS is conceived as a recurrent network of excitatory and inhibitory neurons, with synapses subject to homeostatically regulated structural plasticity. We systematically tested various aspects of stimulation, including electrode size and montage, as well as stimulation intensity and duration. Our results suggest that transcranial stimulation perturbs the homeostatic equilibrium and leads to a pronounced growth response of the network. The stimulated population eventually eliminates excitatory synapses with the unstimulated population, and new synapses among stimulated neurons are grown to form a cell assembly. Strong focal stimulation tends to enhance the connectivity within new cell assemblies, and repetitive stimulation with well-chosen duty cycles can increase the impact of stimulation even further. One long-term goal of our work is to help in optimizing the use of tDCS in clinical applications.

scholarly journals Long-Term Enhancement of NMDA Receptor Function in Inhibitory Neurons Preferentially Modulates Potassium Channels and Cell Adhesion Molecules

2022 ◽  
Vol 12 ◽  
Author(s):  
Dan Xia ◽  
Xinyang Zhang ◽  
Di Deng ◽  
Xiaoyan Ma ◽  
Samer Masri ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Primary Auditory Cortex ◽  
Inhibitory Neurons ◽  
Brain Diseases ◽  
The Impact

Effectively enhancing the activity of inhibitory neurons has great therapeutic potentials since their reduced function/activity has significant contributions to pathology in various brain diseases. We showed previously that NMDAR positive allosteric modulator GNE-8324 and M-8324 selectively increase NMDAR activity on the inhibitory neurons and elevates their activity in vitro and in vivo. Here we examined the impact of long-term administering M-8324 on the functions and transcriptional profiling of parvalbumin-containing neurons in two representative brain regions, primary auditory cortex (Au1) and prelimbic prefrontal cortex (PrL-PFC). We found small changes in key electrophysiological parameters and RNA levels of neurotransmitter receptors, Na+ and Ca2+ channels. In contrast, large differences in cell adhesion molecules and K+ channels were found between Au1 and PrL-PFC in drug-naïve mice, and differences in cell adhesion molecules became much smaller after M-8324 treatment. There was also minor impact of M-8324 on cell cycle and apoptosis, suggesting a fine safety profile.

Evaluation and Diagnosis of Brain Diseases based on Non-invasive BCI

2021 ◽  
Author(s):  
Zuoting Song ◽  
Tao Fang ◽  
Jing Ma ◽  
Yuan Zhang ◽  
Song Le ◽  
...  
Keyword(s):  
Brain Diseases ◽  
Non Invasive

scholarly journals Flexible Potentiometric Sensor System for Non-Invasive Determination of Antioxidant Activity of Human Skin: Application for Evaluating the Effectiveness of Phytocosmetic Products

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Aleksey V. Tarasov ◽  
Ekaterina I. Khamzina ◽  
Maria A. Bukharinova ◽  
Natalia Yu. Stozhko
Keyword(s):  
Antioxidant Activity ◽  
Human Skin ◽  
Skin Diseases ◽  
Silver Chloride ◽  
Potentiometric Sensor ◽  
Sensor System ◽  
Non Invasive ◽  
Pet Film ◽  
The Impact

In contemporary bioanalysis, monitoring the antioxidant activity (AOA) of the human skin is used to assess stresses, nutrition, cosmetics, and certain skin diseases. Non-invasive methods for skin AOA monitoring have certain advantages over invasive methods, namely cost-effectiveness, lower labor intensity, reduced risk of infection, and obtaining results in the real-time mode. This study presents a new flexible potentiometric sensor system (FPSS) for non-invasive determination of the human skin AOA, which is based on flexible film electrodes (FFEs) and membrane containing a mediator ([Fe(CN)6]3–/4–). Low-cost available materials and scalable technologies were used for FFEs manufacturing. The indicator FFE was fabricated based on polyethylene terephthalate (PET) film and carbon veil (CV) by single-sided hot lamination. The reference FFE was fabricated based on PET film and silver paint by using screen printing, which was followed by the electrodeposition of precipitate containing a mixture of silver chloride and silver ferricyanide (SCSF). The three-electrode configuration of the FPSS, including two indicator FFEs (CV/PET) and one reference FFE (SCSF/Ag/PET), has been successfully used for measuring the skin AOA and evaluating the impact of phytocosmetic products. FPSS provides reproducible (RSD ≤ 7%) and accurate (recovery of antioxidants is almost 100%) results, which allows forecasting its broad applicability in human skin AOA monitoring as well as for evaluating the effectiveness of topically and orally applied antioxidants.

scholarly journals Transcranial Magnetic Stimulation as a Tool to Investigate Motor Cortex Excitability in Sport

2021 ◽  
Vol 11 (4) ◽  
pp. 432
Author(s):  
Fiorenzo Moscatelli ◽  
Antonietta Messina ◽  
Anna Valenzano ◽  
Vincenzo Monda ◽  
Monica Salerno ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Motor Coordination ◽  
Cortical Excitability ◽  
Non Invasive ◽  
Motor Cortex Excitability ◽  
Invasive Method ◽  
And Control ◽  
The Impact

Transcranial magnetic stimulation, since its introduction in 1985, has brought important innovations to the study of cortical excitability as it is a non-invasive method and, therefore, can be used both in healthy and sick subjects. Since the introduction of this cortical stimulation technique, it has been possible to deepen the neurophysiological aspects of motor activation and control. In this narrative review, we want to provide a brief overview regarding TMS as a tool to investigate changes in cortex excitability in athletes and highlight how this tool can be used to investigate the acute and chronic responses of the motor cortex in sport science. The parameters that could be used for the evaluation of cortical excitability and the relative relationship with motor coordination and muscle fatigue, will be also analyzed. Repetitive physical training is generally considered as a principal strategy for acquiring a motor skill, and this process can elicit cortical motor representational changes referred to as use-dependent plasticity. In training settings, physical practice combined with the observation of target movements can enhance cortical excitability and facilitate the process of learning. The data to date suggest that TMS is a valid technique to investigate the changes in motor cortex excitability in trained and untrained subjects. Recently, interest in the possible ergogenic effect of non-invasive brain stimulation in sport is growing and therefore in the future it could be useful to conduct new experiments to evaluate the impact on learning and motor performance of these techniques.

Numerical Simulation of Heat Transfer Mechanisms in Spray Cooling

2010 ◽  
Author(s):  
Eelco Gehring ◽  
Mario F. Trujillo
Keyword(s):  
Heat Transfer ◽  
Heated Surface ◽  
Spray Cooling ◽  
Impingement Zone ◽  
Ongoing Work ◽  
Efficient Suppression ◽  
A Cell ◽  
Cooling Behavior ◽  
Free Surface Capturing ◽  
The Impact

A primary mechanism of heat transfer in spray cooling is the impingement of numerous droplets onto a heated surface. This mechanism is isolated in the present and ongoing work by numerically simulating the impact of a single train of FC-72 droplets employing an implicit free surface capturing methodology. The droplet frequency and velocity ranges from 2000–4000 Hz, and 0.5–2 m/s, respectively, with a fixed drop size of 239 μm. This gives a corresponding Weber and Reynolds range of 10–170 and 330–1300, respectively. Results show that the impingement zone is largely free of phase change effects due to the efficient suppression of the local temperature field well below the saturated value. Due in part to the relatively high value of the Prandtl number and the compression of the boundary layer from the impingement flow, a cell size on the order of 1 μm is necessary to adequately capture the heat transfer dynamics. It is shown that the cooling behavior increases in relation to increasing frequency and impact velocity, but is most sensitive to velocity. In fact, for sufficiently low velocities the calculations show that the momentum imparted on the film is insufficient to maintain a near stationary liquid crown. The consequence is a noticeable penalty on the cooling behavior.

scholarly journals The brain timewise: how timing shapes and supports brain function

2015 ◽  
Vol 370 (1668) ◽  
pp. 20140170 ◽  
Author(s):  
Riitta Hari ◽  
Lauri Parkkonen
Keyword(s):  
Human Brain ◽  
Brain Imaging ◽  
Brain Function ◽  
Temporal Dynamics ◽  
Generative Models ◽  
Network Activity ◽  
Brain Diseases ◽  
Specific Information ◽  
Non Invasive ◽  
The Brain

We discuss the importance of timing in brain function: how temporal dynamics of the world has left its traces in the brain during evolution and how we can monitor the dynamics of the human brain with non-invasive measurements. Accurate timing is important for the interplay of neurons, neuronal circuitries, brain areas and human individuals. In the human brain, multiple temporal integration windows are hierarchically organized, with temporal scales ranging from microseconds to tens and hundreds of milliseconds for perceptual, motor and cognitive functions, and up to minutes, hours and even months for hormonal and mood changes. Accurate timing is impaired in several brain diseases. From the current repertoire of non-invasive brain imaging methods, only magnetoencephalography (MEG) and scalp electroencephalography (EEG) provide millisecond time-resolution; our focus in this paper is on MEG. Since the introduction of high-density whole-scalp MEG/EEG coverage in the 1990s, the instrumentation has not changed drastically; yet, novel data analyses are advancing the field rapidly by shifting the focus from the mere pinpointing of activity hotspots to seeking stimulus- or task-specific information and to characterizing functional networks. During the next decades, we can expect increased spatial resolution and accuracy of the time-resolved brain imaging and better understanding of brain function, especially its temporal constraints, with the development of novel instrumentation and finer-grained, physiologically inspired generative models of local and network activity. Merging both spatial and temporal information with increasing accuracy and carrying out recordings in naturalistic conditions, including social interaction, will bring much new information about human brain function.

scholarly journals Analytical Model for Estimating the Impact of Changing the Nominal Power Parameter in LTE

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
A. B. Vallejo-Mora ◽  
M. Toril ◽  
S. Luna-Ramírez ◽  
M. Regueira ◽  
S. Pedraza
Keyword(s):  
Analytical Model ◽  
Mobile Networks ◽  
Radio Resource Management ◽  
Estimation Accuracy ◽  
Model Assessment ◽  
Power Parameter ◽  
Management Procedure ◽  
Proposed Model ◽  
A Cell ◽  
The Impact

UpLink Power Control (ULPC) is a key radio resource management procedure in mobile networks. In this paper, an analytical model for estimating the impact of increasing the nominal power parameter in the ULPC algorithm for the Physical Uplink Shared CHannel (PUSCH) in Long Term Evolution (LTE) is presented. The aim of the model is to predict the effect of changing the nominal power parameter in a cell on the interference and Signal-to-Interference-plus-Noise Ratio (SINR) of that cell and its neighbors from network statistics. Model assessment is carried out by means of a field trial where the nominal power parameter is increased in some cells of a live LTE network. Results show that the proposed model achieves reasonable estimation accuracy, provided uplink traffic does not change significantly.

scholarly journals Mobile Health (mHealth) and Advances in Noninvasive Diagnosis of Anemia: An Overview

2020 ◽  
Vol 13 (02) ◽  
pp. 042-047
Author(s):  
Thiago Mazzu-Nascimento ◽  
Danilo Nogueira Evangelista ◽  
Obeedu Abubakar ◽  
Emanuel Carrilho ◽  
Diego Furtado Silva ◽  
...  
Keyword(s):  
Mobile Health ◽  
Public Health Problem ◽  
Noninvasive Diagnostics ◽  
Non Invasive ◽  
Palpebral Conjunctiva ◽  
Unified Health System ◽  
Bone Marrow Disease ◽  
Video Frames ◽  
The Government ◽  
The Impact

AbstractAnemia is a public health problem that can have different causes, such as iron deficiency, vitamin deficiency, inflammation, hemolytic anemias, and anemias associated with bone marrow disease. Anemia shows a decrease in the concentration of hemoglobin, a pigmented molecule in the erythrocytes. The objectives of this review were to highlight the impact of nutritional factors on morbidity and mortality caused by anemia and to present different non-invasive approaches that use a smartphone to analyze hemoglobin levels to detect anemia. According to the records of the Brazilian Unified Health System (SUS, in the Portuguese acronym), ∼ 440,000 people checked in hospitals due to anemia between January 2015 and April 2020, with 215,000 deaths. The government spent ∼ 294 million Brazilian Reais (more than 50 million US dollars) on anemia hospitalization cases during this period. There is a worldwide search to provide noninvasive diagnostics and mobile health (mHealth) tools to help diagnosing anemia. The smartphone appears to be a viable device to detect anemia by a camera with colorimetric analysis of images providing a quantitative, instantaneous, and noninvasive result. These images can be obtained as a photograph or extracted from video frames. The review presents three different methods of detecting anemia using a smartphone: i) photoplethysmograph from video obtained from the tip of the index finger, ii) photo of the palpebral conjunctiva, and iii) fingernail photo app. Therefore, it seems urgent that these approaches may be applied in routine clinical diagnosis to allow remote, needy, low-tech locations to have access to anemia screening.

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