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How to Trigger a Synapse

Although it is common to speak of "triggering synapses," it is more accurate to say "triggering neural impulses." The synapse is the connection point between two neurons (nerve cells); it does not "fire" or generate electrical impulses.

The main body of the neuron is the soma, where electrical impulses are processed. Dendrites branch off the soma; they are the "input" part of the neuron and gather signals from adjacent neurons. The axon is a long neural fiber extending from the soma; this "output" structure transmits information. The synapse is the connection between the axon of one neuron and the dendrites of another.

A neuron is negatively charged relative to its surrounding fluid. This "resting potential" is maintained by ions passing through the neuron such as Na+ and K+. An external stimulus causes the neurons to undergo a series of changes, resulting in the transmission of an electrical impulse to another neuron.

Instructions

- 1
  Receive an external stimulus (incoming information from dendrites at the synaptic connection with other neurons) and cause Na+ (sodium) ions to flow into the cell. Change the charge of the neuron in a positive direction, away from its resting potential, as positive ions enter the soma.
- 2
  Trigger an action potential -- in other words, "fire" the neuron -- when the charge at the base of the axon (the axon hillock) hits the threshold point. Allow the K+ ions to flow out of the cell and begin the cell's move back toward its resting potential.
- 3
  Pump ions in and out of the neuron to bring it back to its resting potential.
- 4
  Respond to the action potential at the base of the axon (the axon hillock) by generating a chain reaction that travels down the length of the axon, section by section, until it reaches the synapses with neighboring neurons.
- 5
  Begin the cycle again. Stimulate the dendrites of the neighboring neurons at the synapse. If there is enough change in electrical charge, they will reach their thresholds and generate action potentials as well. If there is not enough stimulation to the neighboring neurons, they will not be triggered and will not fire.

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