Electrophysiology facts for kids

Electrophysiology is the study of the electrical properties of biological cells and tissues. It involves measurements of voltage change or electrical current flow on a wide variety of scales from single ion channel proteins, to whole tissues like the heart. In neuroscience, it includes measurements of the electrical activity of neurons, and particularly action potential activity.

Definition and scope

Classical electrophysiologic techniques

Classical electrophysiology involves placing electrodes into various preparations of biologic tissue. The principle types of electrodes are: 1) simple solid conductors, such as discs and needles (singles or arrays), 2) tracings on a printed circuit boards, and 3) hollow tubes filled with an electrolyte, such as glass pippettes. The principal preparations include 1) living organisms, 2) excised tissue (acute or cultured), 3) dissociated cells from excised tissue (acute or cultured), 4) artificially grown cells or tissues, or 5) hybrids of the above.

If an electrode is small enough in diameter (on the order of microns), then the electrophysiologist may choose to insert the tip into a single cell.

Many particular electrophysiological readings have specific names:

• Electrocardiography - for the heart
• Electroencephalography - for the brain
• Electrocorticography - from the cerebral cortex
• Electromyography - for the muscles
• Electrooculography - for the eyes
• Electroretinography - for the retina
• Electroantennography - for the olfactory receptors in arthropods

Images for kids

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  "Current Clamp" is a common technique in electrophysiology. This is a whole-cell current clamp recording of a neuron firing due to it being depolarized by current injection

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  A schematic diagram showing a field potential recording from rat hippocampus. At the left is a schematic diagram of a presynaptic terminal and postsynaptic neuron. This is meant to represent a large population of synapses and neurons. When the synapse releases glutamate onto the postsynaptic cell, it opens ionotropic glutamate receptor channels. The net flow of current is inward, so a current sink is generated. A nearby electrode (#2) detects this as a negativity. An intracellular electrode placed inside the cell body (#1) records the change in membrane potential that the incoming current causes.

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  Schematic drawing of the classical patch clamp configuration. The patch pipette is moved to the cell using a micromanipulator under optical control. Relative movements between the pipette and the cell have to be avoided in order to keep the cell-pipette connection intact.

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  Scanning electron microscope image of a patch pipette.

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  In planar patch configuration, the cell is positioned by suction. Relative movements between cell and aperture can then be excluded after sealing. An antivibration table is not necessary.

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  Scanning electron microscope image of a planar patch clamp chip. Both the pipette and the chip are made from borosilicate glass.

See also

In Spanish: Electrofisiología para niños