Now THIS Is a Synapse
Every time I read about the synapse, the all-important junction between two neurons, the cartoon above pops into my head. It shows the gist of how a synapse works: An electrical pulse enters the cell on the left and activates those little blue balls, called vesicles, to release their chemical contents, called neurotransmitters. The neurotransmitters spill out into the space between the cells, called the cleft, and activate those blue rectangles, called ion channels. The channels trigger the cell on the right to fire its own electrical pulse, or action potential, and this message travels on to the next cell. It’s pretty neat. Our brains are full of trillions of synapses, each with the capability of converting an electrical signal into a chemical one and back again.
My doodle is conceptually useful for understanding many neuroscience studies. It helped me visualize, for example, how researchers record the messages of brain cells, and how the synapse plays a role in developmental disorders, and how the firing patterns of all of these synapses provide our brains with a sophisticated coding scheme.
The downside of the cartoon synapse is that it gives a false impression. It makes it seem as if the synapse is simple and all figured out, when actually it’s mostly baffling. I was reminded of its complexity by a study published in today’s issue of Science. Researchers in Germany used an array of techniques — including Western blot, mass spectrometry, electron microscopy, and super-resolution fluorescence microscopy — to create a three-dimensional model of a typical synapse in the adult rat brain.
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