Types of synapses and how they work in the brain

These are the different ways in which neurons communicate with each other.

When we think about the way the brain works, we often fall into the simple: we assume that it is an organ that 'generates' emotions and thoughts, as if its functioning can be described in terms of its overall functioning. But the truth is that the key to what we think, feel and do lies at a microscopic scale, at the level of neurons.

These nerve cells are mainly responsible for generating a constant flow of information that travels from one side of the nervous system to the other and is processed by the different organs of the brain. But, once again, the key to understanding the psyche is not to be found in something as easy to isolate and observe as a neuron. It is to be found in what we know as synapses and their different types..

In this article we will see what synapses are and how they are part of the basic functioning of the nervous system of almost any animal.

Synapses: a communication space between neurons

A simple definition of what a synapse is may be the following: it is the connection established between two neurons. the connection established between two neurons which transmit information related to electrical impulses to each other.

Thus, the synapse is not exactly an organ, and it is not even technically an anatomical part of a nerve cell. It is a place where two neurons send information to each other to affect the functioning of the other.

In many cases, synapses are established between one end of a nerve cell and the other end of a nerve cell. between one end of a part of the neuron called the axon, and the dendrite, a part of the receiving neuron.a part of the receiving neuron. However, there are also other connections in which synapses are established, for example, from one axon to another axon.

Types of synapses

The different types of synapses can be classified in different ways. Let's see.

According to how the information is transmitted.

On the other hand, it is important to note that although the function of the synapse is to provide a context in which one neuron can either propitiate or inhibit the occurrence of an electrical impulse in another neuronThe synapse is not usually an electrical signal, at least in the case of human beings.

This is because there are two main types of synapses, which are as follows.

Electrical synapse

In these cases, there is an electrical current that passes from one neuron to anotherdirectly. In humans, this type of synapse is only present in some parts of the retina.

Chemical synapse

In most of the human nervous system, this is the only type of synapse that exists. In this synapse, the electric current that reaches the end of the neuron closest to the nerve cell to be influenced generates the release of certain chemical substances, called neurotransmitters, which travel through the synaptic space.

Some of them are captured by structures called synaptic receptorswhich then trigger one process or another depending on the molecule that has reached them (or, in some cases, are momentarily blocked).

According to their location

From the point at which a neuron communicates with another neuron through the synaptic space, the following types of synapses are possible.

Axosomatic

In this case, the terminal button of the axon comes into contact with the surface of the soma, i.e. the body of the nerve cell. with the surface of the soma, i.e. the body of the nerve cell..

Axodendritic

This is the type of synapse par excellence. In it, the axon comes into contact with the dendritic spines of the dendrites.

Axoaxonic

One axon comes into contact with another.

How do neurotransmitters work?

We have already seen that a large part of the mechanics of synapses is based on the use of neurotransmitters, which are a very diverse range of neurotransmitters. are a very varied range of molecules that, in some cases which, in certain cases, also act as hormones if they pass into the bloodstream.

Although this aspect of neuroscience is extremely complex and each substance is associated with hundreds of different interactions that also vary depending on the context, the part of the nervous system in which they act and their effects on the different neuronal receptors, it can be said that the fundamental role of these particles can be divided into two: excitation and inhibition.. In other words, at a synapse, a neurotransmitter can increase the probability that a nerve impulse does not appear in the post-synaptic neuron, or it can increase it.

On the other hand, neurotransmitters do not always have a direct action on the nerve cells that receive them. For example, some of them do not even reach their destination, and are captured by receptors of the same neuron that has released them to be subsequently broken down and recycled, and others, despite reaching the postpsynaptic neuron, only influence it indirectly, by activating a series of second messengers. by activating a series of second messengers that interact with many elements of the nerve cell before generating an effect beyond this.