Within the Brain Stem, the structure called Reticular Formation is identical to Soul or Spirit described in religious scriptures and philosophical writings. Description from wholedude.com. I searched for this on bing.com/images
The Reticular Formation (Integrative Systems) Part 1
reticular formation- activating and connecting the brain
Introverted individuals are in possession of a more easily stimulated reticular formation and so are less likely to seek out stimulation, while extroverts actively seek out stimulation because theirreticular formation is somewhat underactive. It could be hypothesised that addicted patients are in possession of an underactive reticular formation and so therefore crave stimulation.
The reticular formation is a set of interconnected nuclei. This “web of gray matter” runs vertically throughout the brainstem and has connections with the cerebrum. This has over 100 neural networks that use different neurotransmitters that function in: Somatic motor control, Cardiovascular control, Pain modulation, Sleep and consciousness, and Habituation. The two components of this formation are the ascending and descending reticular formation.