Closing the Gaps – Inside and Out

So, considering how seamlessly this intricate process works together, do all those gaps within our neurology actually matter? Yes, there’s a ton of distance embedded in our bodies. But so what? The biochemical / neuroanatomical processes of our sensory processing systems make those gaps seem almost beside the point. If we can’t even notice the distance embedded in our systems, why spend all this time talking about it?

Because separation matters. For all its virtual invisibility, it serves a purpose – and an absolutely critical purpose, at that. It protects us and it connects us. On the one hand, it keeps us safe from people and things which can injure us, if we stand too close. Nobody’s going to object to a few feet of space between them and a chain-saw-wielding worker wearing ear plugs who’s not aware they’re nearby. Closing that distance when the worker’s turning around with the running saw can cause you to lose a limb – or your life. Likewise, when you’re approached by someone who seems threatening, you pull back to put some space between them and yourself – buying some time to figure out what to do.

Just as distance buffers us from threats on the outside, it also ensures we can function properly on the inside. As we discussed earlier, our disparate organs and appendages need to be separate, in order to do their jobs. But there’s something even more integrally useful at work here, for separation sets the stage for the dynamic process of connection at our most intimate, cellular level. If there were no synaptic clefts between millions upon millions of axons and dendrites, electrical sensory data could likely still travel the length of nerves from skin or source to brain, and back again. But without the synaptic clefts, electrical impulses wouldn’t need to be converted into that wealth of neurotransmitters which color our lives and drive our experiences.

Now, there are purely electrical synapses in our systems which conduct signals directly from one nerve cell to another. They have little “bridges” of protein that cross the gaps and make two-way communication possible between those cells. Electrical synapses are fast – and they can be found in parts of the nervous system which rely on speed and synchronization of reactions. But they’re also simple. And unlike chemical synapses (which “recharge” at each synapse) they run out of “juice” as they pass through successive synapses. The nature of the information being transmitted along their lines doesn’t change much (aside from losing signal strength, due to resistance in the neurons along their routes). Electrical synapses work together with chemical synapses in ways we’re really only beginning to understand, and their activity is very different in nature from their neurotransmitter-powered partners.

Chemical synapses, by comparison, are slower, but they’re also more varied. And they’re intricately connected with each other in dynamic networks of interaction which modulate the sensory data as it’s moving throughout the system. Adjoining neurons can excite each other, or they can inhibit each other… or they can do a combination of both. The signals passing between axons and dendrites and cell bodies don’t simply get passed along like a baton going from one relay racer to another. It’s more like a game of “Telephone”, where their strength may be modulated “up” or “down”, or even transformed into something different. The signal strength is also boosted with each chemical synapse, so the messages getting through are more complete than electrical signals would be across equivalent distances. The intricacy and complexity of these interactions would take years to discuss – and we’re learning more every day – but there’s a lot going on, and the differences in how our neurotransmitters negotiate crossing those myriad clefts can mean the difference between joy and pain, life and death.