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Neuroscience

The Three-in-One Brain

The nervous system is the biological support for the human mind.  The brain is the tool we use to face and try to understand life, but is it reliable as an instrument for acquiring knowledge? Do we really see what is there?  Do we perceive reality objectively?

Although it is true that the brain constantly receives stimuli, it is also true that we do not perceive these stimuli at all, meaning that they enter our brains in a subliminal way(under the threshold of our level of consciousness), and we are affected by them.

It is worthwhile to take a look at the structure of our brain, to try and understand this phenomenon and the influence it can have on our capacity to see reality objectively.

“In our heads, we still have cerebral structures that are very similar to those of a horse and a crocodile,” according to neo-physiologist Paul MacLean from the National Institute of Mental Health, in the U.S.

MacLean developed a model of the human cerebral structure that is known as the “brain trio,” where the human brain is made up of three parts:

• The R-Complex or reptilian brain, (the crocodile we have inside).
• The limbic brain system (the horse).
• The neo-cortex (the part that is distinctively more “human”).

These three parts, although very different anatomically and with regard  to functionality, overlap each other.  The reptilian brain is underneath and the neo-cortex above the other two, in a perfect representation of the ascendant evolution of life.

• The R-Complex or reptilian brain, according to MacLean, is the “oldest” part, evolutionarily speaking.  This brain is similar in its structure and function to those of reptiles, hence the name.  It is that part of the brain that regulates the impulses or animal instincts that are indispensable for the survival of the species, such as the “fight or flight response,” as well as basic metabolic functions such as eating, sleeping, mating, etc.  It is oriented towards action and learns through repetition.  It has very little capacity to adapt to change.
• The limbic system is also called the middle brain.  It is that portion of the brain that is situated immediately under the cerebral cortex.  It includes important centers such as the thalamus, hypothalamus, hippocampus and the cerebral amygdale.  All mammals have these structures;  they are the seat of emotions.  This is where we process emotions: sadness, anguish,  intense happiness, fear and aggression.  For example, patients with damage to the amygdale are not able to recognize the facial expression of happiness or sadness.
• The limbic system is oriented towards emotions and learns through association. That’s why it is important for memory development. For example, when we smell a familiar smell and it takes us back to a situation from the past, we are using the limbic system.
• The cerebral cortex or neo-cortex is the “newest” part of the human brain.It covers and engulfs the more primitive R-Complex and limbic systems.  The neo-cortex is the seat of higher cognitive functions, starting with the ability to reason.  The greatest part of our thoughts or plans, language, imagination, creativity and the capacity for abstract thought comes from that region of the brain which crowns the nervous system.  Supposedly, the great achievements of humankind  have been generated in this part of the brain.

Bear in mind, however, that the neo-cortex is not alone and that the “three brains” interact with each other.  Continuing with McLean’s example, it’s as if in our brain there is a crocodile, a horse and a human co-habitating and “decisions” are made among the three, (although they do not always agree with each other).

For example, the level of vigilance of the cerebral cortex depends on the impulses it receives from the thalamus (which is part of the limbic system, or rather the horse). This explains how if something catches our attention and enthusiasm, we pay attention quickly; whereas if something is boring, the thalamus stops sending impulses to the neo-cortex and we feel sleepy.  Therefore, it is the horse within us that decides what is interesting and what is not.

“We only see that which we know,” said Goethe. Through the analysis of the brain structure, we can start to understand that objectivity depends on an adequate management of our cognitive system.  When our “inner horse” doesn’t want to see something, it will simply make the cerebral cortex ignore it.

The concept of CONSCIOUSNESS acquires a more profound significance when we understand the barriers we must overcome to have access to a faithful and objective view of reality:

• A level of alertness that will activate the neo-cortex, to be capable “to reason”.
• Sufficient motivation to overcome the resistance of the limbic system which associates each stimulus with the subliminal emotional memory of our experiences.
• Self-control to overcome the barrier of instinctive impulses that make us act without processing reality beforehand.

The biological support of the human mind is the nervous system and all of its functions stem from this triple brain. Only CONSCIOUSNESS can make our real BEING govern our brains to attain knowledge in such a way that we will be permitted access to true reality beyond all the barriers.