For thousands of years, everyone from great thinkers, priests and philosophers to psychologists and neuroscientists have battled to understand human consciousness.
As far back as the ancient Maya and Inca four millennia ago, whole civilizations have struggled to define consciousness. Countless philosophers since then as well as many leading minds in many different fields today continue to do so.
There are many questions relating to what consciousness is from a philosophical standpoint…
But, up until recently, there were just as many questions on the physical side too:
Specifically, which region of the brain is necessary for consciousness?
In the past few years, scientists think they might have found at least part of the answer to this latter question…
To understand the answer though, we need to know a little about how the human brain works:
What are the main parts of the brain?
In order to comprehend what part of the brain controls consciousness, it is useful to understand a little more about what the different parts of the brain are and what they do.
The brain consists of three major parts and a couple of minor but important ones. These include:
- The cerebrum: this takes up the majority of the brain’s volume. It controls intelligence and reason, emotions and memory as well as other sensory and cognitive abilities.
- The cerebral cortex: the main part of the outer part of the cerebrum is your cerebral cortex, which is the part which processes the sensory and motor data. Of interest to us and the study of consciousness, it may also be responsible for controlling our awareness.
- The cerebellum: The cerebellum is smaller and is positioned towards the rear of the brain. It controls things like movement and balance.
- The brain stem: connects both hemispheres of your brain to the spinal cord. Your sleep, blood pressure, breathing and several other involuntary functions are controlled here. Critically, to the study of consciousness, the brain stem is also thought to control arousal.
- The thalamus: situated beneath the cerebrum, the thalamus is a group of neurons which passes sensory data to your cerebral cortex.
Where is consciousness in the brain?
Scientists trying to figure out which part of the brain is responsible for consciousness already understand some of the basics which are required for consciousness. These include:
- The state of being awake, psychologically and physiologically
- Being able to know and perceive things
They have also looked at patients at times when consciousness was absent in order to see the differences.
A great many studies have been conducted. In recent years, they’ve started to show clear results…
Perhaps none more so than the team under Michael Fox at Beth Israel Deaconess Medical Center in Boston, which is part of Harvard Medical School.
The Harvard study
Back in 2016, in an effort to analyze the brain stem’s responsibility for arousal and its connection to which region of the brain is necessary for consciousness, the team at Harvard studied 36 hospital patients.
All of these patients had some form of damage to their brain stems. Some were conscious and some were in comas.
The scientists found that:
1) Brain stem damage
Most of the unconscious patients had damage to a specific part of their brain stem which the conscious patients did not have. This led the scientists to suspect they have located the part of the brain stem responsible for arousal.
2) Links to parts of the cerebral cortex
Following links from that specific portion of the brain stem to parts of the cerebral cortex in the cerebrum (specifically one part under the left temple and one part deep behind the center of the forehead) – both of which had been indicated as being related to awareness in other studies – they think they have also identified two other parts of the brain which play key roles in controlling or facilitating consciousness.
What part of the brain is responsible for consciousness?
To recap, from the experiment conducted by the team, we now know that it is very likely that the parts of the brain responsible for consciousness are the:
- Brain stem
- Two sections of the cerebral cortex
More importantly, it is the network of neural pathways between these parts of the brain – called the Reticular Activating System – and the way they interact with each other which seems to make consciousness possible.
If anything interrupts the chemical signals which are sent along the Reticular Activating System, a person can experience altered states of consciousnesses.
This may be responsible for the altered states of consciousness experienced by people with the sacred plant brew ayahuasca. As it contains MOAIs, a Monoamine Oxidase Inhibitor, ayahuasca increases levels of noradrenaline and serotonin. These may, in turn, increase activation of the ascending reticular activating system.
Why is this useful?
For people in an unconscious state that are unable to wake up, there may be a possibility for some sort of therapy as scientists start understanding what parts of the brain control consciousness – and thus, what parts to target. This would be similar to the way deep brain stimulation is currently being experimented with as a treatment for Parkinson’s Disease.
It also might be possible to stimulate some parts of the brain to address depression as well as a variety of consciousness disorders.
While this theory of consciousness discussed above is based on the scientific model of the brain producing consciousness, there is another theory that consciousness may actually be non-local.
This implies that consciousness is not something generated by the brain; rather it is something that exists by itself. This theory is based on having out of body or non-local experiences in modified states of consciousness that can take place in lucid dreams, deep meditative states, or induced states with sacred plants such as ayahuasca.
The theory of non-local consciousness is more aligned with spiritual systems that talk about parallel universes, reincarnation, and other non-physical phenomena such as the spirit realm and energetic beings. In these systems, the consciousness of a being comes from a source that is beyond the physical realm. We are not speaking of a specific source as may be defined in some systems, but something that is still a mystery or unknown to us.
One of the most interesting ways to explore the topic of consciousness is through having personal experiences in different states of consciousness. One of the ways to do this is by ingesting the sacred plant brew ayahuasca. This should be done with the proper mindset and in the right setting, such as a well-managed and safely organized retreat at the Spirit Vine center which is located in the jungle, the native habitat of the plants. With the proper preparation and support structure for integrating the experiences, the ayahuasca experience gives people a chance to witness first-hand what is consciousness and how far we can go with it.