Chapter 4: Neuroscience and consciousness

If you could look right inside a brain and see everything that was happening there, would you then understand consciousness? That is what this chapter opens with.

And yes, some would say yes. Materialists and identity theories would agree that, of you could see and understand everything of the brain, then the problem of consciousness would be solved entirely. However, any of the theorists that believe that consciousness is something extended, something other would disagree. Because after all, the mind, the soul is something that isn’t physical, so how could examining the brain help with understanding it?

Noë is one of these people, who says ‘you are not your brain’. We always have tried to look at consciousness as something inside the brain but what if it isn’t there? What if it is somewhere else in the body, or even outside of it? You wouldn’t find it by studying matter and neural connections. This is what is the called the fallacy of neurocentrism – believing that everything happens inside the brain.

Then, there are also the mysterians, who seem to believe that there is never a way to understand consciousness and many would also say that we are not meant to understand it. They, too, would thus disagree that examining the brain would help not in the slightest bit when it comes to understanding the consciousness. Some other mysterians also simply believe that at this point in time and technology, we will never understand conscious, but maybe in the future we might.

Interesting is that nobody flat out said that the brain has nothing to do with consciousness, they just disagree on what extend it does. The naked eye doesn’t reveal much about that big grey lump in our heads, however, attaching some electrodes or looking at a slice through a microscope helps a lot.

What is a human brain? ;) (exercise 1)

It’s said to be one of the most complex things in the universe, holding over 80 billion neurons and trillions of neural connection. You can understand why it is hard to grasp everything that the brain does. But those neural connections don’t end with the brain. They are also spread out over the entire body, and with the spinal cord together form the Central Nervous System (CNS).

Quick recap of the brain:

• Brainstem (medulla, pons, midbrain): essential for life. Helps cardiac and respiratory functions, controls sexual hormones etc.
• Cerebellum: motor control
• Thalamus: sensory input
• Cortex (central, pre-frontal, thalamus): pretty much everything else

The brain is relatively systematic in it’s build, with two halves, four lobes per half and an overall of six layers. This is relatively the same as to other animals, though our brain has much more grey matter and a larger brain to body ratio.

Relating back to the hard and easy problems, theorist often first try to tackle the easy problems by looking at what they call ‘neural correlates of consciousness’ (NCC’s)

What does correlations before cause mean?

The study of NCCs means that you study some neural activity and try to link it to something someone consciously does. It thus helps contrasting the imaging against something someone does unconsciously.

Most often this is tested in vision, particularly when an image can mean two things (take those famous staircase painting that seem to go up and down at the same time). This is called rivalry – two image that want to both be seen. It is impossible to see them both at the same time so, even if your eyes do not move, the image keeps going back and forth in your brain. Binocular rivalry is the same thing, except then it’s about different images from each of the eyes. This was first tested on monkeys, who would flip a lever on which direction the currently saw a disc turning (both eyes seeing a different disc). In the visual cortex, they didn’t find any different impulse even when the monkey flipped the lever, but they did find some interesting input in the Inferior Temporal Cortex (IT). The problem is that we are not 100% sure that monkeys are as conscious as we are, so we cannot be sure.

It’s a great example of consciousness, because the two images seem to compete against each other. They used to thing the flipping was because f the movement of the eyes, but because it still happened when you do not move the eyes, it suggest it is something in the brain itself, not the eyes.

Like you probably already know, correlation is not causation. This is the same with NCCs. We do not know if the activity in the IT of the monkey can from the flipping of the mental image, or maybe simply from the action of flipping the lever. Sometimes things are obvious. If the bell rings in school and everybody rises to their feet, you can conclude it is because of the bell that everybody does so. But if you’re at a station and the platform slowly gets fuller, and then a train appears, you might incorrectly conclude that hey, maybe the people made the train appear. Of course, you use common sense and know that both the people and the train are related to the schedule the train is on, but you get the point. So watch out assuming that neural activity is caused by consciousness or vice versa. It might not be the case.

What is conscious vision?

Francis Crick (co-discoverer of DNA) had a similar approach to the hard problem as many; we need to solve the easy problems first. He wanted to find not NCCs but NCs of conscious experiences. They mostly looked at visual experiences because as they claimed, ‘humans are largely visual creatures’.

Together with Christof Koch, they looked for something in the brain that corresponded with the vivid picture of the world that we see. They didn’t quite find it though. They did state that the front of the brain seems to be more in ‘automatic zombie’ mode, while in the back of the brain, stimuli are constantly competing and moving, creating a series of visual snapshots that have the implication of motion.

They, however, got stuck on the consciousness of it all. If some actions of some cells are conscious, while others are not, where then lies the difference. What give those specific cells and actions that little bit extra?

The thing with searching for NCCs is that you believe in the hard problem, but at the same time deflect it and, like everyone before you, wind up saying that it applies to some brains area’s but not others, without an explanation as to why. Some say it has to do with the amount or strength of impulses, while others say it has to do with the type of sensory experience. Crick and Koch hypothesise that ‘it is the transient results of the computations which correlate with qualia; most of the computations leading up to those results are likely to be unconscious’. Yes, that explains a lot… not.

That there is a specific place where consciousness happens is what Dennett calls the Cartesian theatre – the place where all that makes consciousness happen comes together. A dualistic approach to a monist point of view. Descartes had his pineal gland and James believed that the entire brain was involved in creating consciousness.

In the 18-hundreds, the idea of a ‘bridge locus’ arose; the idea that somewhere there was a metaphorical bridge spanning between matter and the consciousness – and the idea was formed that neural activity near the region of this bridge had to be high. However, though several visual areas have been found with high neural activity, a specific location for this so called ‘bridge’ was never discovered.

Keep in mind though, the difference between simple brain imagine during activity and the research to NCCs, which is particular to the difference of conscious and unconscious activity.

For instance, there had been research with people in a Permanent Vegetative State, people who seem to be awake without consciousness. Loud sounds, bright flashes and pain stimuli all led to some activation in the brainstem, thalamus etc, but nothing in the higher brain regions.

The cells in V1 (primary visual cortex) for instance, register primary visual input, but cannot tell the difference between whether it is because of eye movement or movement of the world that something in the vision shifted. Phenomenal experience is thus higher up the visual tract. This implies that prior to all conscious experiences, there are unconscious ones, but again – Cartesian theatre – there is something special, magic, that makes something turn conscious, which cannot be explained.

And it’s really easy to just ignore the problem – to continue the research and not address the hard problem. But it thus seems that NCC research doesn’t bring us any closer to the truth about consciousness either.

Then there is also the criticism that they forget there are two types of NCCs, the P- and the A-consciousness, and that not all that is consciously experienced is up for accessible explanation (P-consciousnes without A-con).

Why is there competition for consciousness?

It is not ethical to put electrodes in the human brain (by now also not in the brain of an animal either) but the fMRI made is possible to perform the monkey test with the lever on humans too. They found many area’s of the brain involved with the switch, the flipping of the lever and started a research to possible patterns.

Back in 1901, the theory was already introduced that both the inputs give each other negative feedback. The dominant one sends out signals to inhibit the other – but, while being inhibit the other also sends out signals to inhibit. Thus, you create a back and forth, causing the images to flip.

Though the research for binocular rivalry is interesting, it also has quite some issues with it. Firstly, it only provides us with correlations, which say nothing concrete. Secondly, it does not remove that magic, Cartesian theatre component of why this is conscious at all.

Unconsciousness and the brain

Imagine your friend in the hospital. Her eyes are open, but she cannot move, cannot speak. Occasionally her finger might twitch. Is she still in there, conscious and tapped in an unmoving body? Or is she in a PVS, as mentioned before? In this case, sensory imaging such as FMRI can make a big difference.

Anaesthetics can bring somebody from a conscious to an unconscious state – so why does that happen? Modern technology seems to suggest anaesthetics suppress action in the thalamus, among other things and thus prevent sensory input from being processed, and thus reducing a person to an unconscious state. This suggest that the thalamus can be a ‘consciousness switch’. It also shows that consciousness is not ‘all or nothing’. It is a gradual field that allows you to be semi- or partially conscious as well. However, not all anaesthetics such as ketamine of NMDA work like this.

Though it seems that a useful way of studying consciousness is the absence of it, it is still hard to define. Do we mean wakefulness? Awareness?  What do we define as unconscious if we don’t know what conscious is? See the problem? If you learn something new, like a language, could you tell us exactly when you stopped struggling with it and you switched from consciously having to focus on it to doing it unconsciously well? Probably not.

This leads to the dual-process theory, the idea that there are two types of processes – automatic and effortful. New things are often effortful, while familiar things are automatic. Focussing on automatic can often make them effortful and often also suddenly perceived a lot harder. (Exercise 2)

Pain

Pain hurts. Pain can hurt a little or really bad and there is no way of telling if my pain is worse than your pain, just like I can’t be sure that my red is the same of your red.

Even so, neural activity and pain seem to be correlated, so there is a way to measure it. Even so, pain remains a subjective experience, and even if the neural activity is the same, there is no way of saying two people experience the same amount of pain. There seems to be a proper correlation between pain and the amount of neural activity when it is expected, unexpected, sudden or long lasting. But this still doesn’t tell us anything. Does the pain cause the activity, does the activity cause the pain? Or are both caused by something else?

Some people, paralysed from the waist down, still have a reflexive reaction when a leg or foot comes in contact with something. Is this pain? They can’t feel it, but the body still reacts. This seems to go against the notion that knowing you are in pain causes you to feel it. If the paralysed person sees a massive cut on their leg, they rationally know they should be in pain, even if they don’t feel it.

It’s something interesting to think about.

Exercises

4.1. Try drawing an image of the brain. How much do you know? Where would you guess it’s located?

4.2. You automatically ignore the sound of your own breathing. Not try to effortfully ignore it. Hard, huh? Some things are necessary to be automatic and impossible to be effortful.