Extracellular Stimulation
Extracellular Stimulation - Related Videos
04:31
In Vitro Stimulation and Visualization of Macrophage Extracellular Traps
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2025
This video demonstrates in vitro stimulation of macrophage extracellular traps (METs) in human monocyte-derive macrophages using different inflammatory stimuli such as TNF-alpha, PMA, and HOCL. The video also demonstrates the method of SYTOX dye staining of METs for visualization.
07:26
Stimulation of Vascular Endothelial Cells Using Neutrophil Extracellular Traps in the Presence of Low-Density Lipoprotein
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2025
A series of methods is described, including the isolation of low-density lipoprotein (LDL) from human plasma, differentiation of HL-60 cells into neutrophil-like cells, preparation of neutrophil extracellular traps (NETs) in the presence of LDL, and stimulation of human aortic endothelial cells with a mixture of NETs and LDL.
11:02
Combining Transcranial Magnetic Stimulation and fMRI to Examine the Default Mode Network
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Cited by 17 •
2010
In this article, we examine the methodology and considerations relevant to the combination of TMS and fMRI to examine the effects of brain stimulation on the default network.
14:17
Neutrophil Extracellular Traps: How to Generate and Visualize Them
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Cited by 296 •
2010
Neutrophil Extracellular Traps (NETs) are an important innate immune mechanism to fight pathogenic bacteria, fungi and parasites. Here we describe methods to isolate neutrophil granulocytes from human blood and to activate them to form NETs. We present preparation techniques to visualize NETs in light and electron microscopy.
12:45
Mechanical Stimulation of Chondrocyte-agarose Hydrogels
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Cited by 29 •
2012
The biosynthesis of cartilaginous extracellular matrix by chondrocytes can be affected by application of mechanical stimuli. This method describes the technique of applying dynamic compressive strains to chondrocytes encapsulated in 3D constructs and the evaluation of induced changes in chondrocyte metabolism.
FAQs
Whether a cell fires depends on more than stimulus intensity. The applied signal must produce a sufficient change in membrane potential, and the response reflects the combined influence of amplitude, duration, and frequency. A stimulus that remains below threshold may modulate excitability without driving an action potential, whereas reaching threshold can produce a discrete neural event. This distinction helps investigators separate activation from modulation.
Electrode placement determines where the externally generated electric field is strongest relative to the target cells. Consequently, changing the electrode's position can alter which neural elements experience membrane-potential changes, even when the signal settings remain unchanged. Careful placement is therefore essential when interpreting responses, because an observed effect reflects both the applied electrical signal and the spatial relationship between the electrode and excitable tissue.
Frequency determines how often electrical perturbations are delivered and can therefore influence the resulting neural response over time. In experiments, varying frequency alongside amplitude and duration helps distinguish responses tied to individual stimuli from changes that emerge across repeated stimulation. This parameter is especially relevant when examining synaptic or network behavior, where the measured outcome may reflect coordinated activity rather than a single-cell event.
At the cellular level, the external electric field redistributes charge across the membrane. That redistribution changes membrane potential, which is the electrical difference across the membrane, and can either alter excitability or drive an action potential if threshold is reached. This mechanism connects electrode-generated signals to measurable neural activity and explains why membrane effects are central to interpreting extracellular stimulation experiments.
A basic experiment begins by positioning an electrode relative to the neural tissue, selecting stimulus amplitude, duration, and frequency, and delivering controlled electrical signals. Researchers then examine the resulting cellular, synaptic, or network response. Keeping these variables explicit allows the experimenter to relate an observed change to stimulation conditions and supports comparisons across brain, spinal, or peripheral-nerve contexts.
Extracellular stimulation is useful for mapping neural circuits because researchers can apply signals at defined locations and observe how activity changes elsewhere in the system. It also supports studies of synaptic and network responses, extending analysis beyond whether one cell produces an action potential. These applications help connect local electrical perturbations with broader patterns of neural communication.
In neuroprosthetics and clinical interventions, the same stimulation principles are used to restore or regulate nervous-system function. The relevant design problem is not simply producing activity, but selecting electrode placement and signal parameters that produce the intended modulation. Neuroscience studies therefore provide a foundation for translating controlled electrical effects into approaches for the brain, spinal cord, and peripheral nerves.