When we think of general divisions of the body, the first the comes up is of mind/body. This is a classic Cartesian split, and the thrust of Modern Allopathic Medicine. That something can either be divided into a mechanistic, parts-oriented “body” division, and is thus treated by Allopathic/Western Medicine and pharmaceuticals, or is considered the realm of the “mind”, meaning non-physical, emotionally based, and is treated by modern forms of psychotherapy and psychiatry.
In terms of Eastern/Asiatic Medicines, this split is often described as mind/body/spirit, but the idea of this is to introduce the idea that these concepts interweave and inform one another. This means that you are not just a mechanistic piece of machinery or a mind, you are both, and are a spirit as well, all informing and influencing one another.
In terms of Energy Medicine and Spiritual/Shamanic Healing, the consideration is of the whole, meaning that there is no split. Although there are divisions of the body (like chakras, or levels of the energy body like the etheric, or even the energies within the body like the energetic matrix that at the basest level comprises who we are) we are considered one unit- these energies do not just inform and interweave one another, they are one another, and are reflected in one another. Your physical state is simply a representation of what is going on emotionally, spiritually, energetically.

In terms of development of the human brain, the tribrain system is often the base model. There is a split between the reptilian brain, the limbic brain, and the neocortex. The reptilian brain is that of the dinosaurs, formed first, and responsible for things of a simple, physical nature, such as brute strength, movement, and respiration. The reptilian brain is not a thinking brain, it is what makes up our very basic instincts of survival- our drive to get through a situation no matter what. It makes up the base instinctual part of ourselves, a simple brain that reacts and acts on instinct.

The limbic brain is made up of our higher instincts, and our emotions. The limbic brain drives our behaviors out of feelings- primarily those of fear. This is also the space of our selves that reacts to the hierarchy of needs- fears of being properly taken care of, fed, sexual drives, and basic social skills and ability to gather in groups for a common purpose, as well as wars, arguments, and seeing people different from us as “other” and something to be labeled and feared. This is the caveman brain, and is not capable of higher thought, but of reacting to emotions, mainly fear.

The neocortex is the last of the tribrain model. It is the higher brain, responsible for higher levels of intelligence, insight, and thought patterns. Mathematics, spatial reasoning, foresight, philosophy, technology, language, writing, music, art, architecture- most things you can think, study in school (arguably), or see in modern society are from the development of this region of the brain.

So why am I introducing this concept (or re-introducing?)
Although we consider ourselves to be high-minded, intelligent creatures, the reptilian brain, limbic brain, and the neocortex all react differently and are triggered by different areas in our lives. For example, by understanding that the limbic brain largely comes from a place of fear, a place of war and pointing out of differences, we can understand how when that emotion comes up (fear, anxiety, really any emotion), we can understand why we feel the need to put others down, argue, or even fight.

Limbic Brain Meditation
Let us look at a fear you have. It can be of anything, small or large. Something as simple as a fear of not getting work done on time by the deadline this week to something as complex and loaded as the fear of death and dying.
• Consider the situation you are thinking of in terms of fear
• Feel that fear in your body, how does it affect you physically? What areas of your body does it affect?
• What other emotions come up with that fear? Grief, sadness, anger?
• What does this fear make you want to do? Hide, fight, eat?
• Connect this fear to the drive you discovered. Say this out loud:
example: my fear over losing my parent makes me feel grief, tightness in my chest, nausea, makes me want to hide in my room and never come out, and eat sugar.
• Sit with this understanding for a moment. Let your body understand what you just said out loud.

Do this Meditation every time you feel a strong emotion come up. The limbic brain is a gateway, meaning that it has access to both the reptilian as well as the neocortex. By coming up with an emotion (limbic), understanding your primal drives and decisions derived from that emotion (limbic and reptilian) as well as speaking it out loud and coming to an intellectual understanding/creating a story about this emotion (neocortex), you are linking aspects of this system, and gradually will be able to change how you react to situations.