Three Levels of Mind
The brainstem is equivalent to the reptilian brain, the limbic system developed in the mammals, and the cortex developed to make up the three levels of the human brain.
From Struggle to Healing:
There are quite a number of factors that came together that enabled me to stay the journey that went deep into my feelings and sensations. The cognitive reality I lived with for 55 years of my life was super-ceded by a reality based on my feelings and sensations.