How do nerves transmit information


How do nerves take in information?


Our brain consists of over a trillion nerve cells, and a large part of them are there to process impressions from our environment. The type of transmission is very different from sense organ to sense organ, but they all have one thing in common: They work electrically.

A nerve cell - also called a neuron - can be thought of as a small battery. But how can you transfer information with a battery? The secret lies in the connections between nerve cells. Each cell is connected to up to several thousand other cells via long nerve fibers. Where such a fiber meets the next cell, there is a synapse, a chemical junction. When a synapse is active, it releases chemicals that literally “raise the tension” in the adjacent neuron. If many of these synapses act simultaneously on a single neuron, the tension can increase considerably. And then something unexpected happens: The tension continues to rise, even though the synapses are no longer working, it reaches a peak - and then falls back to its resting value. This so-called “spike” now has enough strength to travel along the entire nerve fiber and, at the end, to activate synapses for the next cell.

Spikes and synaptic activity are the language in which the brain processes information. Sensory impressions now have to be translated into this language. For this, there are so-called “receptors” in every sense organ, which are connected to a number of neurons and whose tension they can influence in exactly the same way as the synapses. In the eye, for example, these receptors are located on the retina. Whenever light strikes a certain point on the retina, the receptors located there become active and trigger spikes in the neurons assigned to them. Since these neurons are spatially arranged in the same way as the receptors on the retina, an image of what is seen is created, similar to a pixel graphic on the screen. However, this is only the first stage of processing. The “raw data” from the sensory organs are now passed through a whole chain of processing steps. Due to the way they are interconnected, each nerve cell in the sensory systems becomes a specialist who only reacts to very specific impressions, for example to a color, a pitch or the position of objects in space. In this way, all aspects of reality that are important to us can be recorded: If a certain aspect occurs in the environment, the corresponding nerve cell becomes active and begins to “fire” spikes. The specialists then in turn serve as suppliers for further nerve cells, which combine the many individual aspects into a coherent overall picture. This gives the impression that we have all information from the environment at our disposal at all times. But this impression is deceptive. Because which aspects are important and what is a coherent overall picture determine the evolution and personal development of every person. That is no reason to no longer trust your senses, but to be aware of their limits.