The cardinal error of modern neuroscience – or more often, naive consumers of modern neuroscience – is its implicit belief that brain mapping will eventually allow it to identify the source of consciousness in the brain.
Now it is absolutely not the case that different parts of the brain do not perform different psychological functions. They do. For example it is beyond doubt at this point that that the occipital cortex is involved in the construction of what eventually become visual images, while the spinal cord, for example, is not. There are masses of neurons in both places, but the two groups do not both process visual information.
For this reason annual conferences of such organizations as Human Brain Mapping or the Society for Neuroscience, as well as many others, feature thousands of poster and lecture presentations of the results of brain mapping efforts, in which neuroscience takes on the important task of determining what sorts of information are processed where in the brain. Eventually this knowledge will improve the treatment of a range of neurological and psychiatric problems; indeed it already is. People with epilepsy and brain tumors routinely undergo “functional scanning” prior to surgery so that their neurosurgeons can know what the functional effects of their operations will be. Moreover in psychiatry, deep brain stimulation (DBS) and transcranial magnetic stimulation (TMS) are used with increasing frequency to treat depression, and eventually other conditions, by stimulating or suppressing neural activity in specific brain regions. For example, stimulation of the occipital lobe is unlikely to alter mood (but to alter vision), while stimulation of the subgenual cingulate cortex can improve mood instantaneously (while leaving vision intact).
Where human brain mapping has gone wrong is in the effort to locate the neural source of consciousness. And to understand this, a clear distinction between consciousness per se and the contents of consciousness must be made.
The distinction is easy to understand by analogy. If I gave you an unlabled compact disk and asked you what song, easily located on iTunes, was on it, you would stick it into a CD player to find out. But if I stopped you and said “no no, tell me without playing it” you would think I was nuts. There are, at this point, what – a million songs on iTunes? The odds of your guessing what song is on the CD are miniscule.
You would know this because you know the difference between a CD and a song. The CD stores the song, and without the CD the song cannot “exist”. But the song is its “own thing” and can be easily replaced by another.
The analogy becomes more useful when we go a step further, and call the CD a medium and the song information. As we all know by now, in the digital age information is encoded as strings of 1’s and 0’s, each one a “bit” or “binary digit,” and these digit-strings – billions of digits long, often – have to be written somewhere. They can’t be written in thin air – yet. But you can write any given string in any number of places – on a flash drive or a hard drive or a CD or, if you have a very good musical memory, in your brain. The reason information can be copied from place to place – from the internet “cloud” to your hard drive to an iPhone flash drive to the earphone speakers into your brain, to take a common sequence – is because there is a “double dissociation” between information and medium. Any given medium can have any string of information written on it, and any given string of information can be written on any appropriate medium.
What bears ad nauseum emphasis, because it is about to have such shocking implications if you have never had the thought before, is that the information cannot exist without a medium. And what this means, in turn, is that the information is always perfectly correlated with, and therefore easily mistaken for, its medium. And vice versa.
I want to say this again, because it is – really truly! – that important:
Information is easily mistaken for its medium, and vice versa.
Okay, now with this idea beaten into our heads – and if you ever lose it, go back to the CD versus Song dichotomy – we need to have one more insight before we are ready to cash it in for the insight that neuroscience is prone to huge mistake in its thinking about consciousness.
The final insight is this. When you play a song, it is very, very easy to become confused about what the medium is. The song is just the song, and is always the song, and you never get confused about that. Miley Cyrus never sounds like Justin Bieber. Wait, bad example. Miley Cyrus never sounds like Sigur Ros. The information strings – the 1’s and 0’s – are totally different. So different, in fact, that you can hear it without seeing the 1’s and 0’s. But the medium blends in to its environment. When you are listening to a song, where is the information? Now shortly I am going to answer that question correctly, but for now I want to empathize with people who don’t know the answer – among whom I was once numbered – and give a variety of plausible answers that you could give without shame; they would all seem reasonable:
- The information is in my mind.
- The information is in my brain.
- The information is in the air between the headphones and my brain.
- The information is in the headphones – its in the movement of the speaker.
- The information is in the wire between the headphones and the iPhone.
- The information is in the iPhone.
- The information is on the flash drive of the iPhone.
And guess what? All these answers are correct. The information is indeed in all of those places as you are listening to a song on your iPhone. The song is a communication between your device and you, and the data is flowing from one to the other. And, indeed, you could trace the song back all the way to Cupertino, California and the Miley Cyrus recording studio as well.
But something fascinating is therefore true. Each of these 7 areas – if we confine our thinking to just these 7 things, your mind, brain, air, headphones, wire, iPhone and flash drive – is very highly correlated with every other. If I could “image” you and your iPhone, I would find evidence of a Miley Cyrus song in every place at once. And if anyone were to forget this, it would be easy for them to become fixated on the idea that the information was in just one of those places. Which is why many people who don’t know anything about electronics feel very confident saying the song “really” is in their iPhone. While others, perhaps more philosophically minded, say the song “really” is in their mind. Who’s right? Both? Neither?
Okay, this said, we’re ready for the last part. Let’s cash our analogy in.
When you have a thought – say the image of this word coming right up in 3, 2, 1 words – yes, the word “words” – where is that thought? Where is “words”?
It is absolutely positively reasonable for you to think that it is in your brain. It is! Your brain is a medium for the information string that makes “words.”
But what is not reasonable – and what modern neuroscience often assumes, or at the very least implies in its dealings with the general public – is to assume that your brain is the only medium in which the information string “words” exists. That would be like saying that the Miley Cyrus song is “really” in the iPhone.
The truth is that there are a lot of different mediums hierarchically layered on top of one another in the brain, and the physical brain – the neurons and so forth – are just one of these layers. And as we will see in Neuroenlightenment, neurons are not the most fundamental layer. Just as the plastic and metal case of an iPhone is not the fundamental medium on which Miley Cyrus songs are stored.
neuroself 
consciousness mapping! How impossible. Although don’t hemispatial neglect patients give clues to consciousness’ “general area”? The burning house task indicates they still perceive things, but are not conscious of perceiving them. Could the superior temporal gyrus and inferior parietal be the ones to study further for consciousness?
What’s the temporal resolution on fMRI and magnetoencephalography anyway? It seems to me that we will finally have a chance to understand the brain when temporal resolutions reach the millisecond range and spatial resolution reaches the micron range.
Well, that’s the big question. Consciousness mapping is impossible if consciousness is not a “thing in the world.” That is, if it is made of neither fermions nor bosons, and has no energy or matter associated with it, and is therefore invisible to the world, then you are right – mapping is impossible. Alternately, if consciousness is made of either fermions or bosons, and what we call consciousness is the inner experience of that component of the universe, then in principle it is mappable. Stating that consciousness mapping is impossible and then hypothesizing particular brain regions where it might be located needs a bit more explanation.
I reread the post. If I understand correctly, consciousness is an un-mappable abstract concept that may not necessarily manifest physically. I agree. It would be like trying to map ‘morality’. Experts may describe their work as ‘mapping the source of consciousness’, however what they are really doing is…attempting to solve the binding problem? Describing multisensory integration for a unified experience? I believe I proved your point at first; consciousness, awareness, and unified experience have been used interchangeably outside academia. My original post then, was really talking about advances in technologies needed to help solve the unified experience problem. That would be exciting, because that is the closest we could get to understanding “consciousness”.
I guess my point with the hemispatial patients was that binding surely has a neural substrate, since lesions inhibit bound cognition.
Hi Peter,
Thanks for the interesting and thoughtful post.
I’m wondering if it’s fair to say that “what modern neuroscience often assumes, or at the very least implies in its dealings with the general public – is to assume that your brain is the only medium in which the information string “words” exists”? As neuroscientists are necessarily focused on brain function/structure, I suspect it’s not that they believe the information is in a single medium, but that the words they chose (reasonably) might lead many others to assume this is so.
On a related note, the notion that I find it’s easier to use (imprecise) dualistic language to help with many neuro-explanations comes to mind – though following such metaphors forward might lead to incorrect conclusions. Moreover, I suspect that neuroscientists are focused on the brain as the most interesting medium given that only information in the brain can be interpreted through consciousness (or so the current evidence suggests).
I’m wondering if you are at all familiar with Damasio’s work, in particular his book “Self Comes to Mind”? He gives probably the most comprehensive analysis and empirically investigated theory of the neural correlates of consciousness to date. I think he is proving those who believe consciousness’s correlates can’t be found incorrect. Also, work on the Default Mode is starting to have important implications for a theory of the neural correlates of consciousness (Qin and Northoff, 2011). However, I would absolutely agree that it is naive to believe that there is a single brain region, e.g., the cingulate cortex (Northoff et al., 2006; Qin and Northoff, 2011) involved in consciousness. It’s easy to forget that the body itself is part of consciousness. And of course, our experience of consciousness, is also a part of consciousness, which can’t be found via scientific observation (although even scientific observation is a part of our consciousness). If anything I would say that a quest for the neural correlates of consciousness is absolutely possible, and a unique endeavor, in that it’s one of the few situations, and perhaps only, where one can objectively observe though empirical investigation that which they are subjectively experiencing, simultaneously.
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