• Sam

Brain Blog Part Two

Updated: Nov 18, 2018



This is the second blog in a series on the Tripartite Brain. In the previous blog, we looked at the most primitive part of the brain, the reptilian brain—the part of the brain that keeps us safe and alive. In this blog, we will take a very brief look at the middle part of the brain, the part of the brain that allows us to feel emotions. In our next blog, we will look at the third, most advanced, part of the brain, the part that allows us to reason, plan, and worry.


Again, please remember that this is a hopefully helpful oversimplification of a very complex and only recently understood way of looking at what it means to be human.


The Limbic System, the Paleomammalian Brain, is the part of the brain we share with lower mammals such as dogs, cats, horses, etc. The Limbic System is responsible for our emotional life. It also has a lot to do with the formation of memories. In many ways, it is the quarterback of the brain. It mediates between the Fight, Flight, Freeze simplicity and immediacy of the reptilian brain and the plodding but nuanced ruminations of the cerebral cortex (or neomammalian brain).


The paleomammalian brain can ask and answer more complex questions than the reptilian brain such as, “Do I like this?” “Does this feel good?” “Do I feel happy?” It is the home of the famous triad of basic emotions: “Sad, Mad, Glad.”


If we leave our dog home alone for a few hours, he is genuinely happy to see us. His tail wags (actually his whole body wags), and he makes a sort of grunting, happy noise. He will often grab an old sock or a chew toy and want to play–to engage with us.


And here is an important distinction between the reptilian and the paleomammalian brains: Mammals can engage in relationships. According to a report published in the New York times on April 17, 2015, “Japanese researchers found that dogs who trained a long gaze on their owners had elevated levels of oxytocin, a hormone produced in the brain that is associated with nurturing and attachment, similar to the feel-good feedback that bolsters bonding between parent and child. After receiving those long gazes, the owners’ levels of oxytocin increased, too.”


The report went on to note, “In a way, domesticated dogs could hijack our social circuits, and we can hijack their social circuits, as each species learned how to raise the other’s oxytocin levels, facilitating connection.”


Mammals have mothering/fathering capacities. Reptiles lay eggs and leave their offspring to fend for themselves. Even lower-order mammals care for their young by feeding them and teaching them how to get food and how to relate to their pack or herd. These rudimentary nurturing and relational behaviors hint at the more complex and human thoughts and interactions that are seated in the final layer of brain, the cerebral cortex.


Next time . . . How being human gets us into--and out of--trouble . . .

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© 2018 by Dr. Sam Pascoe