Engrams: The Traces That Experiences Leave Us In The Brain
We suffered a traffic accident, a red car crashed into our vehicle. This accident caused us a series of injuries from which we ended up recovering, but at the cost of great suffering and anxiety. The day comes when we take the car again, and we notice that when we see any red car, we shudder and get very nervous. The reason for this fact seems logical to most of us. However, what is not so well known is what generates it at the brain level.
That is, we know that various neurons will be activated that will generate different effects, largely mediated by the limbic system. But how exactly are these neurons related to react in a concrete way to situations similar to experiences already lived? In this sense, there are neuronal circuits that are formed throughout development and life, and that after being formed remain more or less stable: we are talking about the engrams
We understand by engram that stable neuronal structure generated by stimulation, whether external or internal, and that is linked to the activation of specific responses, whether unconscious or conscious. The engram is the group of neurons, or neural circuit, which is activated upon the perception of certain information
Another common term to refer to this type of structure is neuronal loop. In summary, it could be understood as the biological basis of a trace or scheme of functioning derived from experimentation, such as the set of brain changes resulting from learning and what we memorize. It would be the process of forming specific neuronal connections that When activated they reproduce the subjective experience that generated the event that gave rise to them.
Engrams can be both sensory and motor, containing the basic programming of how to perceive or act upon stimulation. Both may be related. Although the formation of engrams is unconscious, these structures generate and influence both conscious and unconscious processes. They can trigger the generation of thoughts, emotions, movements or activation of physiological mechanisms.
In our brain there are a large number of these structures, engrams being generic neuronal structures that They participate in a large number of mental and physiological functions It is a system that generates synaptic facilitation and connection between different neurons, generating a closed circuit that reacts to stimulation, in turn awakening other engrams that react and generate different responses.
Training and psychobiology
The formation of engrams occurs due to the coding of experience and the neuronal activation that this generates. Repeated exposure to certain stimulation or derivatives of this cause specific neurons or nerve pathways to be consistently activated. The information that activates them can come from very different sensory pathways or modalities.
At the cellular level, the axon of the presynaptic neuron generates the excitation of the postsynaptic neuron repeatedly, which in the long run generates a change in both in such a way that the efficiency of their intercommunication is improved. It also allows more synapses to be established reinforcing the circuit and connecting with other loops that generate a response to stimulation.
At the neurotransmitter level, the communication of the neurons that are part of an engram is mainly carried out by acetylcholine, although other hormones such as norepinephrine also have a certain effect.
However, it is necessary to take into account so that the engram is fixed It is considered necessary that there be an activation of the limbic system especially those regions linked to motivation, due to the need for us to give importance to a fact in order to generate automatisms.
Its role in memory
Engrams are important in allowing information to be stored in a stable manner and remembering previous information: they are stable neural structures, which will be activated in a certain way and will continue to function in the same way unless changes are introduced or are born. new synapses.
They are essential when it comes to allowing memory storage, thus being the biological basis on which the repetition of certain behaviors or ways of reacting to certain situations is based, for example. Engrams make us sensitive to specific stimulations and make it easier for us to react to them in previously learned ways.
This, for example, causes a person who has suffered some type of aggression or abuse to have generated changes that make them, when faced with similar stimulations (for example, the physical contact of someone of the attacker’s sex, even though the person who is now approaching us is not attacking us), and do not have bad intentions) may react with fear or defensiveness.
We are not saying that all engrams correspond to negative or traumatic experiences, but also to those that generate very positive emotions in us. For example, a child ends up generating engrams that relate the maternal or paternal figure with feelings of security and protection, which is why he may feel bad if they are not there or seek their closeness in case of discomfort.
So far we have mainly talked about the engram as a brain circuit linked to learning and memory But the truth is that engrams are not limited to that sphere: if we think of engrams as brain circuits that are activated by information, aspects such as perception, motor skills (how to walk for example), knowledge (including theory of the mind), language, emotional experience and expression are also determined (although modifications and changes can be introduced) by these structures.
