A century ago, Henry Dale – born on this day in 1875 – discovered that communication between neurons takes place using chemical signals, across terminals known as synapses. Fine branching threadlike dendrites from each cell form synapses when they meet, facilitating the transmission of electrical signals along the neuron. Scientists can now measure the strength of the chemical signals produced. A neuron (left, stained red) receives a signal from another (stained green). Researchers have found that signals are usually stronger at synapses near the bulbous cell body (left, red). Bluish squares (right) represent weaker signals and reddish squares, stronger ones. It is not yet known why this is the case, but it could be key to understanding information processing in the brain.
Written by Andrew Purcell
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