What is consciousness? 

A simplistic explanation could be:

1. it is that which we lose when we fall into deep sleep without dreams, or when we go under anesthesia, 

2. It is what we regain when we recover from sleep or from anesthesia. 

But what is exactly that stuff that we lose under anesthesia, or when we are in deep, dreamless sleep? 

1. A mind which is a flow of mental images. 

2. Mental Images? - The flow of mental images is mind. Images that can be sensory (auditory, visual) patterns.

3.  But we are not passive exhibitors of visual or auditory or tactile images. 

4. We have selves. We have a Me that is automatically present in our minds right now. We own our minds

5.  So in order to have a conscious mind, you have a self within the conscious mind. So a conscious mind is a mind with a self in it.

6. we are only fully conscious when self comes to mind. So what we need to know to even address this mystery is,

   1. how are minds are put together in the brain,

   2. how selves are constructed. 

How are minds put together in the brain?

1. The brain builds mental image, dot by dot. Like the computer screen builds image, pixel by pixel.

2. Everyone of these pixels or dots are actually a neurone. And it just as a pixel it cab ne lit or not. Or lit in various colours. Together all the pixels (neurones) an image is constructed in the mind

3. The same way the audio or a touch is built in the brains - dot by dot. Neurone by neurone.

4. Your mental experience is directly correlated to the activity of these neurones. Various parts of the brain takes care of processing various sensory inputs.

5. These regions of the brains builds mental experience based on their signals that it gets from the neurones.

6. These signal-processing parts pass on the inputs to other parts called association cortex where the record is kept of all things that happened in image processing regions.

7.  And the great beauty is that you can then go from memory, out of those association cortices, and produce back images in the very same regions that have perception. So think about how wonderfully convenient and lazy the brain is. So it provides certain areas for perception and image-making. And those are exactly the same that are going to be used for image-making when we recall information. 

How selves are constructed?

1. For a long time, scientists did not even want to touch this field, because they'd say, "How can you have this reference point, this stability, that is required to maintain the continuity of selves day after day?" 

2. Point to be noted is that we never lose the sense of ‘self‘. That’s one thing that is constant with us every moment of our conscious life. And it’s indestructible and constantly

3. So let me tell you just a little bit about how I came to this. I came to this because, if you're going to have a reference that we know as self -- the Me, the I in our own processing -- we need to have something that is stable, something that does not deviate much from day to day. Well it so happens that we have a singular body. We have one body, not two, not three. And so that is a beginning. 

4. here is just one reference point, which is the body. But then, of course, the body has many parts, and things grow at different rates, and they have different sizes and different people; however, not so with the interior. The things that have to do with what is known as our internal milieu -- for example, the whole management of the chemistries within our body are, in fact, extremely maintained day after day for one very good reason. If you deviate too much in the parameters that are close to the midline of that life-permitting survival range, you go into disease or death. So we have an in-built system within our own lives that ensures some kind of continuity. I like to call it an almost infinite sameness from day to day. Because if you don't have that sameness, physiologically, you're going to be sick or you're going to die. So that's one more element for this continuity.

5. And the final thing is that there is a very tight coupling between the regulation of our body within the brain and the body itself, unlike any other coupling

6. So for example, I'm making images of you, but there's no physiological bond between the images I have of other people and my brain. However, there is a close, permanently maintained bond between the body regulating parts of my brain and my own body.

7. There is the brain stem in between the cerebral cortex and the spinal cord. And it is within that region that we have this housing of all the life-regulation devices of the body. This is so specific that, for example, if you look at the part that is covered in red in the upper part of the brain stem, if you damage that as a result of a stroke, for example, what you get is coma or vegetative state, which is a state, of course, in which your mind disappears, your consciousness disappears. What happens then actually is that you lose the grounding of the self, you have no longer access to any feeling of your own existence, and, in fact, there can be images going on, being formed in the cerebral cortex, except you don't know they're there. You have, in effect, lost consciousness when you have damage to that red section of the brain stem. But if you consider the green part of the brain stem, nothing like that happens. It is that specific.So in that green component of the brain stem, if you damage it, and often it happens, what you get is complete paralysis, but your conscious mind is maintained. You cannot have a conscious mind if you don't have the interaction between cerebral cortex and brain stem. You cannot have a conscious mind if you don't have the interaction between the brain stem and the body. 

There are three levels of self:

1. Proto

2. Core

3. Autobiographical

The first two types are shared with many species. They are really coming out largely of the brain stem and whatever there is of cortex in those species. It's the autobiographical self which some species have.

The autobiographical self is built on the basis of past memories and memories of the plans that we have made; it's the lived past and the anticipated future. And the autobiographical self has prompted extended memory, reasoning, imagination, creativity and language. And out of that came the instruments of culture -- religions, justice, trade, the arts, science, technology. And it is within that culture that we really can get -- and this is the novelty -- something that is not entirely set by our biology. It is developed in the cultures. It developed in collectives of human beings.

Why should we bother about understanding all these:

1. Curiosity

2. Understanding of society and culture and medicine

3. How to enhance our happiness levels

Ref: Self Comes to Mind: Constructing the Conscious Brain Kindle Edition by Antonio Damasio