Esoteric psychology explains that humanoids have three brains:

1. an intellectual brain
2. emotional brain
3. a motor/instinctive/sexual brain

These are not "physical brains" or physical matter. Rather, they are psychological divisions of organized activity. Each brain functions and operates independent of the others, and each one has a host of jobs and duties that only it can accomplish.

When analyzed in more detail, the third brain is understood as having three distinct functions. Thus, the three brains can also be called the five centers:

1. intellectual center, located within the brain: processing of thought; reasoning, logic
2. emotional center, located in the solar plexus and in the specific nervous centers of the grand sympathetic nervous system: feelings
3. motor center or the center of movement, located in the upper part of the dorsal spine: activities of movement, habits, actions of the physical body
4. instinctual center, located in the lower part of the dorsal spine: root impulses and functions of the organism that are not conscious: digestion, survival instinct, etc.
5. sexual center, located in the genital organs: the root power of creation, reproduction, growth, and much more

Each brain or center is a machine that utilizes and transforms specific types of energy. When utilized consciously and intelligently, they harmonize and elevate the human being. Yet, when abused or misused, great disequilibrium, suffering, illness, and even death can result.

In general, all sicknesses are the outcome of the wrong use of the three brains. - Samael Aun Weor, Tarot and Kabbalah

There are two additional centers that are activated when awakening consciousness:

1. The superior intellectual center
2. The superior emotional center

These two can only express themselves through the authentic Astral Solar Body and the legitimate Mental Solar Body [Samael Aun Weor, The Perfect Matrimony].

Quotes about the Three Brains

A perfect equilibrium between personality and Essence, the harmonious development of thought, emotion, and movement, and a revolutionary ethics are what constitute the basis of a fundamental education. - Samael Aun Weor, Fundamentals of Gnostic Education

In the staged arts of long ago, the individual would receive information in his three brains: motor, emotional, and intellectual.  In the schools of today however, only the intellectual brain receives information. Neurosis and the sick states of the mind are due to this. Mental disequilibrium is avoided by balancing the three brains. - Samael Aun Weor, Tarot and Kabbalah

Perfect mental equilibrium is of vital importance for those who want spiritual progress.  Almost all the aspirants of esotericism easily lose their mental equilibrium and usually fall into the most absurd things.  Whosoever yearns for direct knowledge must ensure that their minds are in perfect equilibrium. - Samael Aun Weor, The Perfect Matrimony

The "I" exercises control over the five inferior centers of the human machine. [...] Whosoever wants to dissolve the "I" must study its functionalism within the five inferior centers. We must not condemn the defects; we must not justify them either. What is important is to comprehend them. It is urgent to comprehend the actions and reactions of the human machine. Each one of these five inferior centers has a whole set of extremely complicated actions and reactions. The "I" works with each one of these five inferior centers. Therefore, by deeply comprehending the whole mechanism of each one of these centers, we are on our way to dissolving the "I." - Samael Aun Weor, The Perfect Matrimony

Learn more about the Three Brains

• The Three Brains (audio lecture)
• The Three Brains and the Five Centers (lecture)
• Erroneous Functioning of the Five Centers (audio lecture)