This densely packed spatial arrangement and the power of the climbing fiber led us to wonder whether the climbing fiber’s input alone could generate an electric field large enough to influence the activity of neighboring Purkinje cells. Their somas are spaced only a few microns apart. Purkinje cells are positioned in a single layer with their dendrites parallel to one another. The famous dendrites of the Purkinje cell resemble the sea fans of a coral reef. VGlut2 indicates inputs from the climbing fiber Purkinje Cell in red, and VGlut2 in green. These climbing fiber to Purkinje cell synapses are excitatory, and the resulting currents are often immeasurably large. The climbing fiber originates in the inferior olive and each one of approximately 7 axon branches wraps around the proximal dendrites of 7 matching Purkinje cells. We looked within the cerebellum at the climbing fiber to Purkinje cell input because it is a classic synapse known for its power and specificity-both good hallmarks for ephaptic effects. It is probably for this reason that, while every neuron in principle has the ability to influence others via its electrical field, research in this area is quite sparse. Instead, we very often rely on inference and exclusion to identify ephaptic effects. Unlike for example, chemical transmission, there are few manipulations that allow one to specifically and accurately manipulate a neuron’s electric field and its ephaptic coupling. However, ephaptic coupling is notoriously difficult to study. These fields, if strong enough and/or positioned precisely, are able to influence the electrical excitability of neighboring neurons near-instantaneously. Because neurons are electrogenic, they produce electric fields. In principle, ephaptic coupling is quite simple. In this study, we examined an even less-discussed, third form of communication that is not mediated by chemicals or physical connections: ephaptic coupling. When the conversation gets more exotic, we might be referring to an actual physical connection between neurons that allows charge to flow freely between them-often referred to as gap junctions or electrical synapses. You can find more experiments like this one at, and in my books Kitchen Science Lab for Kids (Quarry Books), Outdoor Science Lab for Kids (Quarry Books), and my upcoming book STEAM Lab for Kids: 52 Creative Projects Exploring Science, Technology, Art and Math (available wherever books are sold).Most of the time we talk about communication between neurons we are referring to the transmission of chemicals across the synapse. However, a colder glow stick will glow longer since it’s reacting and releasing light energy more slowly. How brightly the sticks glow depends on the temperature of their environment.Īdding heat to a chemical reaction makes it happen faster, so adding heat to a glow stick makes it produce more light energy for a short period of time. When you mix the chemicals together by cracking the glow stick, they react to make new chemicals and release excess energy in the form of light, transforming chemical energy into light energy. No light can be released until the chemicals are mixed together. Glow sticks contain potential energy in the form of chemicals: fluorescent dyes and a chemical called hydrogen peroxide. Stored energy is called potential energy. Step 10: Optional: Let her test the same thing using different colored glow sticks to see whether some colors glow brighter than others.Ĭrack two glow sticks to activate them. Step 9: Have your child put the sticks in order from brightest to dimmest. Ask your child if she can see a difference between them. Step 8: After three minutes, remove the glow sticks from the water and place them side-by-side on the table with the room temperature glow stick. Step 7: Help your child set a timer for three minutes and ask her to observe the glow sticks to see what is happening. Step 6: Use the tongs to place one glow stick in the hot water and one in the ice water. Step 5: Ask whether she thinks a glow stick will glow brighter in hot or cold water. Have her shake the sticks up to mix the chemicals inside together. Step 5: Let your young learner bend each of the three glow sticks until it cracks (to activate it). Step 4: Use the permanent marker to label one stick “hot,” one stick “cold,” and the third stick “room temperature.” Step 3: Have your child add ice to a second cup and fill it with cold water. Step 2: Fill one foam cup with hot water from the tap. Tell her that the bubbles contain chemicals. Ask what she sees when she looks at it closely. Step 1: Give your child a glow stick to observe. At least 3 glow sticks that are the same size and color
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