Question: What Is the Biological Basis of Consciousness?

Sam Geen answered on 28 Jun 2013:

Hey! I know nothing about this, so I asked my very excellent sister, who studied psychology, for advice. She says:

“Ack, you had to ask the hardest question in the book! But it’s also a very important and majorly popular question right now and even though we don’t have any answers that are very satisfying (at least to my mind) everyone wants in on it. There are certainly a lot of crazy theories flying around though, from those that claim consciousness doesn’t exist, has no biological basis, that it does but scientific answers based on what electricity firing in brain cells are doing can’t fully explain why we feel stuff in a particular way (e.g. how does stuff happening in your brain lead to your experience of the colour red, or the taste of pizza – this is what people call the hard problem of consciousness), to those that think it’s something to do with quantum mechanics (a silly and unnecessary idea but one supported by some big names in science).
Are you confused yet? So I am, and I’m not ashamed to admit that I’ve read many big fat books on the issue without feeling I’ve really understood the question any better.

Part of the problem is that consciousness itself is hard to define (we all think we know what it is, but how do we break this idea down into something concrete enough for science to poke at?), has blurry boundaries (have you ever drifted in a state between sleep and wakefulness in which you felt like you were partly conscious and yet not as much as normal? And which animals can be called conscious and to what degree?) and is very likely modular (reliant on different parts working in unison or even alone) rather than an as an overarching black or white state.

Another issue is that the term has two dimensions, 1. to do with arousal (ie. awake, kind of awake, very ‘excited’) and 2. its contents (i.e. what is a person conscious of (pizza, a rose, a dog) and what are the qualities of this (cheesy? Smelly? Wet?).)
The first is the easiest to answer, as a history of patients in comatose states has shown that parts of the brain, such as the thalamus, midbrain and pons, have to be working for a person to be aware and ‘conscious’ i.e. awake at all, so we can say with certainty that these areas are part of the answer.

However, the second part of the issue is much harder and is without doubt one of the most complex questions facing contemporary scientists. Again, certainly the cerebral cortex is involved (this is the wrinkly bit on the outside of the brain), but this is a very varied and complex area so saying it plays a part isn’t a very satisfactory answer, as there’s loads of stuff that goes on in the cerebral cortex (and thalamus, midbrain, pons) that have nothing to do with consciousness.

To give you an idea about how difficult the problem is, consider a crazy condition called ‘blindsight’ – people with this condition have brain damage to an area called ‘V1’ and as a result say that they are blind and that they have no conscious awareness of vision – yet they can still avoid objects or even post letters through letterboxes placed at a variety of angles. In other words they can’t see, but they’re still using their eyes to do stuff! So V1 is essential for conscious awareness of vision, but not ‘unconscious vision’, nor for conscious awareness of smell, hearing, sound, touch or any other things we would associate with consciousness. This means that different parts of conscious awareness can be knocked out whilst others remain, or even be knocked out and yet the information is still acted upon.

There is good evidence that many many such areas of the brain work together to form consciousness by exhibiting “enhanced synchrony”, aka a state where the cells sort of communicate in a harmonious pattern. If this is true it means that the biological basis of consciousness is a bunch of widely dispersed areas of brain that are ticking away separately, with the synchrony “binding” them together into the apparently seamless whole we experience as consciousness.

One last note, but it’s also very important to note that, whilst most answers to this question focus on the brain, the body is also a vital biological component as it’s from our senses that consciousness gets the inputs it works on! Indeed, it is very likely that consciousness evolved as part of a programming package to increase the chances of these squish body things we all have (are?) staying out of danger and producing baby bodies with more success.

I fear that this is an awfully long answer to basically say ‘really, we don’t really understand very well yet’ but you did ask what many people consider to be the most complex question there is!”