This article was based on the Mind Science Foundation presentation, “The Neuroscience of the Unconscious,” by Heather Berlin.
|Heather Berlin The Neuroscience of the Unconscious|
The Brain as a Machine
Neuroscience is the study of how the brain creates all of our subjective experiences, thoughts, feelings, and emotions. The brain is a complex piece of machinery made up of cells called neurons, which basically serve to send information. There are over 100 billion neurons in the human brain, and each one has about 1,000 to 10,000 synapses, or connections.
There is a significant amount of money being spent on research to map the human brain. Unfortunately, even if we could map every connection in the brain, this would not give us the answers as to why the neurons and chemicals give us our subjective feelings.
You can think of the brain as an information processing machine. It includes our thoughts, feelings, and perceptions. However, even though there is a whole field dedicated to studying the neural basis of consciousness, much of what happens in this piece of machinery is outside of our awareness.
We only become aware of our intention to make a decision after the brain has made it. That leaves us to question what happened in our subconscious to guide the behaviour. How do these unconscious processes impact our behaviour?
To test this in a lab, we can use stimuli that appear so quickly the person does not realise they have seen anything even though the brain is processing it. Alternatively, we can present stimuli in a very subtle form, so the brain is processing it even though the person is not aware of it. These are known as subliminal messages.
What is interesting about these kinds of subliminal stimuli, is that even though the stimuli do not change, the perception in your mind does. We want to track the neural basis of perception or what changes in your mind when you see something versus when you don’t.
This kind of information is getting into your brain and is being processed without your awareness. If you were aware of all of the information that was coming into your brain all day long, it would be overwhelming. The unconscious is limitless and can process a great deal of information while it only filters out very few pieces.
The same stimuli can be perceived in different ways based on what we have been exposed to. What we see in our mind, does not necessarily correlate to what is out there in the real world. The brain is interpreting physical stimuli and manipulating it based on its experiences.
We want to track the neural basis of consciousness of what we are perceiving, and we can do this by using these bistable images. You can prime someone to see something particular or then you can change their focus to see a different image in the same picture. Even though there may be two perceptions of the same image, you can never see them both at the same time. We want to track what is happening when your brain decides what it sees.
The Process of Conscious Awareness
In order to do this, you can look at the brain when something comes into context. You will see the neurons start to fire. You can think of the brain as having a competition among the neurons. Some are trying to suppress the others, and they are constantly battling each other to come into consciousness. There is a coalition of neurons occurring across the large circuit of the brain.
The thinking is that the neurons start to fire in sync with each other. They are in coordination with each other, similar to an orchestra where the instruments come together even though they are not all playing the same note. It’s a coordinated action.
The global neuronal workspace of consciousness is a theory that says that when something is presented subliminally, it activates the primary visual cortex. You have a spike of activation early on when the image is presented. As it moves further into consciousness, higher-order visual areas are activated. When it reaches consciousness, you get activation in the prefrontal areas in feedback loops. The more brain activation, the more it comes into conscious awareness.
The End Goal
There are many other theories that have been presented to try to determine how we process information. Our understanding of how the conscious versus unconscious brain functions has come a long way in the past decades, but there is still much that we do not understand. The implications of a better understanding of the subconscious can help us improve how disorders of the brain are treated. In the end, the long-term goal of these studies is to help people live better and happier lives.