He Reptilian brain , Also called complex R, and S the phylogenetically oldest area of the brain, and takes care of the most primitive and instinctive functions. Its main objective is to ensure the survival of oneself and of the species.
Carl Sagan in his book Cosmos, talks about the theory of the triune brain from which comes the idea of the reptilian brain.
Yellow: Neocortex. Light orange: Middle brain. Dark orange: Reptilian brain.
Explain it as follows:
"Inside the skull of each of us there is something like the brain of a crocodile. Surrounding this complex lies the limbic system of the mammalian brain, which evolved tens of millions of years ago into ancestors who were mammals but not yet primates. It is an important source of our mood and emotions.
And finally on the outside, living in an uncomfortable truce with the most primitive brains below, is the cerebral cortex. It evolved millions of years ago in our primate ancestors."
The reptilian brain is located in Brain structures Deeper functions for the most basic functions. It occupies 5% of our brain mass, and mainly its task is to react to stimuli of the environment.
It is not a reflective area, nor does it take into account the past or the future. Mainly it initiates fight or flight responses to face the threats of the environment. It is also responsible for involuntary and unconscious behaviors, such as cardiac and respiratory functions.
In addition, it seems that our fear of change comes from the reptilian brain. For, to ensure survival, it evaluates what is known as safe and the unknown as dangerous.
The theory of the triune brain
One of the best known models for understanding the complex structure of the brain was the triune or triune brain theory. It was developed by American neuroscientist Paul MacLean from 1950.
Although this theory has been very influential over the years, several of its elements have been revised to update the more recent neuroanatomic findings.
The MacLean model attempts to describe the mammalian brain as a series of evolutionary developments.
From this perspective, the brain is essentially a reptilian brain to which two sections have been added: the limbic system And the neocortex. This has meant a process of evolution of more than 250 million years, since the mammals arose with a different lineage.
Then the development of the brain has taken place progressively, integrating increasingly complex functions. The most primitive functions continued to be processed by the same ancient structures.
Carl Sagan, in his famous book Cosmos, explains that the structure of the brain reflects the phases through which it has passed. Describing MacLean's theory, he states that the deepest part of the brain is the phylogenetically older part. It is located in the brain stem, the one in charge of the most basic functions. They include rhythms of life, heartbeats and breathing.
Sagan also points out that in the depths of our skull is something similar to the brain of a crocodile: the complex R. That is"the seat of aggression, ritual, territoriality and social hierarchy."
Surrounding this structure is the limbic system. This system evolved from our mammal ancestors, and is a source of our moods and emotions .
On the outside is the cerebral cortex, which evolved from the primate ancestors. This is where ideas, inspirations, where you read and write. In short, where the conscious life is regulated, what differentiates man from other animals.
These three parts of the brain do not function independently. On the contrary, they are connected by multiple paths and influence each other.
The three brains evolved in the form of layers, as explained below:
Reptilian brain
It consists of the Brain stem , the Basal ganglia , The reticular system and the cerebellum . As already indicated, it is concerned with ensuring our survival. It is the first filter by which we process the information.
Through the reptilian brain we act in the face of threats, emitting an attack or flight response. Their functions are explained in more detail below.
Limbic brain
This brain arose in early mammals. It allows us to memorize the answers for use in future situations. It is composed of the thalamus, the amygdala (Emotions), the Hypothalamus , the Olfactory bulbs , The septal region and the hippocampus (memory).
The limbic brain is a second filter, and categorizes the stimuli as they cause pain or pleasure. Thus, when these emotions are experienced, the limbic brain will keep them in memory and generate behaviors of approach or struggle.
It is the seat of value judgments that we sometimes do unconsciously, and that have a great influence on our behavior.
The cognitive-executive brain (neocortex)
This part is what differentiates us from the rest of the animals, because this brain allows us to consciously process the information.
Here, the higher intellectual processes are generated, such as social behavior, empathy , Inhibition, planning, logic, imagination, processing of future experiences, etc.
Functions of the reptilian brain
The reptilian brain has been used by some authors as a concept to explain why we are often afraid, we resist changes, we are not flexible or just look for our survival.
The reptilian brain keeps us in a safe environment away from danger, although it tends to be somewhat rigid and repetitive.
Seth Godin, an American entrepreneur, speaks in his book"Are you essential?"Of the reptilian brain, indicating that:
"The lizard brain is hungry, afraid, angry... And it just wants to eat and be safe. He cares what others think, because the status of the tribe is essential for their survival. [...] But, of course, survival and success are not the same thing."
According to Godin, the reptilian brain in humans is the source of resistance to getting what we want. For it is the reason why we are afraid and sometimes, rather than protect us, prevents us from advancing.
Apparently, the reptilian brain is associated with a series of functions that you can read below:
- Basic vital functions: the reptilian brain seems to regulate those basic and unconscious functions such as blood pressure, respiration, body temperature, eye movements, balance or swallowing.
- Automatic coping responses to environmental stimuli and challenges. Typical responses to danger, for example, are rapid fighting reactions. Either escape or search for hiding.
Thus, reptile survival instincts are attacks to protect your own life or to escape or to hide. Humans can act like reptiles before an unexpected stimulus that scares us, a threat or possible harm.
In fact, before a stimulus like a loud noise, our most immediate reaction is the shock and the paralysis. This is an example of the mechanism of the reptilian brain to react quickly to potentially dangerous stimuli of the medium.
- Basic emotions such as anger or aggression. Showing anger would be a manifestation of the reptilian brain, in which the individual tries to prove that he is stronger than his enemy. Thus, it prevents the other from starting an aggression, imposing respect and frightening him. It is a way to protect yourself or your loved ones from others.
- Avoid pain and seek pleasure or pleasant sensations automatically. This also keeps us in a comfortable and safe environment.
- The revenge. Faced with a conflict perceived as unjust, the reptilian brain can react by triggering a need for reprisals. Thus, he punishes others for actions or words that have previously harmed the individual.
It is an instinctive behavior that can lead to spread conflicts and wars, when in reality the most adaptive would be to solve the problem in another way. That is, in a more reflective way and with the participation of cortical structures.
- Territorial and tribal behavior. Our reptilian instincts lead us to increase our security through the defense and definition of the space in which we live. Therefore, one struggles to maintain and care for one's own home and belongings.
In addition, the reptilian brain tries to be in tune with the other members of our"tribe", avoiding to show behaviors or ideas that do not fit with those of that group.
- Reproductive need. It is what leads us to feel attracted to other people of our species with whom we have common qualities. This maintains the survival of the species.
Reptilian brain and decision making
The reptilian brain is a name that has been popularly given to an area of the brain called the fluted . Belongs to Forebrain , And sends information mainly to the basal ganglia. At the same time, it receives information from the entire cerebral cortex, limbic system and thalamus.
As mentioned, it is an older structure in the timeline of evolution. It seems that the establishment of connections between the striatum and the Pale globe Was decisive for the evolution of amphibians to reptiles. This helped the reptiles to successfully adapt to a totally terrestrial habitat.
In this way, the pale balloon acts as a kind of filter before executing the action. By making the information coming from more primitive structures be processed before reacting.
The same thing happens in mammals, but at a higher level, since they use cortico-striated circuits. That is, first the sensory regions of the thalamus that capture the stimuli of the medium project to cortical regions, which then innervate the striatum to act.
Thus, the information that comes from the environment passes through structures that process it, making sure that the best decision will be made. This is because not always an impulsive and involuntary response, typical of the"reptilian brain", is the best option.
Therefore, a participation of cortex and an interaction of cortex with the reptilian brain, causes us to behave and think more flexibly.
In short, to make decisions, our neocortex interprets the information that comes from the reptilian brain and the limbic brain. Thus, it tries to inhibit impulses that are not adaptive and deploy behaviors more appropriate for the situation.
References
- Godin, S. (2011). Are You Essential? Barcelona: Management 2000.
- The theory of the Triune Brain. (January 22, 2013). Retrieved from Blue Smart Europe: bluesmarteurope.wordpress.com.
- Lee, A.M., Tai, L.H., Zador, A., & Wilbrecht, L. (2015). Between the primate and 'reptilian' brain: rodent models demonstrate the role of corticostriatal circuits in decision making. Neuroscience, 296, 66-74.
- Naumann, R.K., Ondracek, J.M., Reiter, S., Shein-Idelson, M., Tosches, M.A., Yamawaki, T. M., & Laurent, G. (2015). The reptilian brain. Current Biology, 25 (8), R317-R321.
- Reptilian complex. (S.f.). Retrieved on January 22, 2017, from Psychology Wiki: psychology.wikia.com.
- Reptilian Coping Brain. (S.f.). Retrieved on January 22, 2017, from Coping Skills for Kids: copingskills4kids.net.
- Sagan, C. (1982). Cosmos (6th ed.). Barcelona: ed. Planet.
- The Brain from Top to Bottom. (S.f.). Retrieved on January 22, 2017, from McGill: thebrain.mcgill.ca.