A Theory of Consciousness

Lately, I’ve been reading Oliver Sacks’s new-ish book Musicophilia. While it’s not quite the tour de force that The Man Who Mistook his Wife for a Hat was, it’s gotten me thinking once again about the neurology of consciousness, and after a few days’ contemplation (and a few years spent reading neurological books), I think I finally have a rough sketch for my own theory of how consciousness comes into existence. Of course, I’m not a neurologist. I don’t know the details of how all this works, and none of it is based on empirical evidence, but that’s the beauty of the Internet: you can talk about ideas abstractly. And, since that’s what I’m good at, that’s what I’m going to do. So, here goes: consciousness.

There are a few structures which are vital to conscious experience. These are:

  • The thalamus
  • The brainstem
  • the prefrontal cortex (and the rest of the cerebral cortex as well)

The other structures are more involved in the contents of consciousness. They are the raw material that the conscious structures process. Here’s how it seems to me that consciousness happens:

  1. Sensory information enters via the brainstem.
  2. The brainstem preprocesses the information and sends it to the thalamus.
  3. The thalamus takes in the preprocessed sensory information and combines it with information about the state of the cortex itself.
  4. The thalamus relays this information to the relevant cortical structures. The prefrontal cortex may play a role here in organizing the arrival of the information, and perhaps in weighting it emotionally.
  5. The cortex processes the sensory information, and the prefrontal cortex reads the results and generates judgments based on emotional weighting from the limbic system. It may generate some of its own emotional reactions as well.
  6. The prefrontal cortex sends the interpreted brain state back to the thalamus. There may also be other loops between the thalamus and the other cortical regions.
  7. The processed mental state enters the thalamus, along with a new set of sensory information.
  8. Repeat.

Of course, this says nothing about memory formation, which is very important for making sense of conscious awareness. It just so happens that I have a theory for how memories form as well.

  1. An emotional signal is sent by the amygdala (or some other part of the emotional system) to the hippocampus, which “reads” sensory information currently being process, thus forming connections between the disparate kinds of information.
  2. This association is stored in the temporal lobe. When the area where the memory structure is stored is activated, the temporal lobe re-activates the relevant structures (those whose particular activity patterns were linked by the hippocampus), and the remembered event is re-experienced.

I’m not really sure how a memory would be recalled in this model, though. I’d venture to guess that it’d have something to do with the prefrontal cortex sending a signal to the temporal lobe, in order to retrieve the memory for comparison to current events.

This little model (and I’ll say it again, I’m not a neurologist. Not even close, so think about this model in the spirit in which it was intended: as a useful idea, not as anything approaching a theory) does shed some useful light on certain kinds of mental illness and the effects caused by certain sorts of brain damage.

  • Schizophrenia: It’s well known that in schizophrenia, the prefrontal cortex is not functioning as it should. Without a properly-functioning cortex, judgments based on memories and sensory information cannot be made properly, and sensory information does not get integrated properly. Also, the prefrontal cortex’s inhibitory connections are less functional as well, which would seem to explain not only the disorganized and unintegrated thought patterns associated with schizophrenia, but also the hallucinations, which could be the result of sensory information going to the wrong place or being integrated improperly. Or, perhaps, the hallucinations and delusions might have something to do with the fact that, without prefrontal cortical direction, the various cortical structures can no longer properly regulate their output.
  • Anterograde amnesia: with damage to the hippocampus comes difficulty forming long-term memories. In this model, that would be because the structure which associates the various neural states with one another is either incapable of doing so, or else it is incapable of moving them into the temporal lobe for permanent storage.
  • Thalamic coma: this may also apply to comas in general, as well as minimally-conscious states, but thsi model only really has something to say about thalamic comas. When the thalamus is damaged, not only can external sensory information not enter the cortex, but the cortical state itself is also prevented from being communicated to the cortex, so there is an absence of both sensation and cognition. The thalamus, however, is divided into two parts, one of which communicates primarily to the cortex, and the other of which is mostly responsible for preprocessing and relaying sensory information. If only the sensory-preprocessor (in the case of vision, this is the lateral geniculate nucleus) were to be damaged, the patient would still likely be able to achieve conscious awareness, but there would simply be no sensory information for them to process.
  • Encephalitis lethargica: in patients with this disorder (which is, according to Oliver Sacks, an extreme form of parkinsonism), the patient is mostly functional, but they are unable to initiate much activity (if any). In this model, that would be because of damage or inactivity of the limbic system, which is crucial in communication emotional meaning to the prefrontal cortex. In patients with severe parkinsonism, there may be difficulty seeing the relevance of actions, and therefore, the actions are not generated. This can also occur with certain kind of brainstem and prefrontal lesions.
  • Depression: in this disease, the prefrontal cortex is known to be less active. However, unlike in schizophrenia, its integrative functions must still be intact. However, its emotional functions become impaired, leading to difficulty forming memories (since the PFC cannot communicate the emotional necessity of remembering something to the hippocampus, and would likely have difficulty sending retrieval signals, too), lack of motivation (since the significance of actions would become unclear), and depressed mood or flat affect (since everything would have the same emotional significance).

I won’t go any further, for fear of over-inflating my ego and for starting to make claims that I have no hope of arguing for. But this, I think, is at least something to get people thinking. Of course, there are a billion things that I haven’t taken into account: the left versus right hemisphere functional disparity, the effects of neurotransmitters, and no doubt I’ve left out quite a few very important brain structures.

New Short Story: “The Long Wait”

After a few days’ work, I’ve finally finished another short story. Lately, I’ve been getting the disturbing feeling that, if I keep actually finishing stories like I’ve been doing lately, then I might set a precedent and accidentally amount to something.

Anyway, enough disjointed self-deprecation. I present to you: The Long Wait. It tells the story of Derek, who’s spent the last ten years trying to escape from the Harvesters, even though he knows they will find him eventually. As he wanders through the desert, trying to scratch a living out of the sand, his life becomes an a miserable burden, and he begins to wonder if there’s any reason to go on living.

(Beware: Existentialism ahead!)

Exhaustion

I haven’t really written anything of consequence for a while, and for that, I apologize. Let me explain.

For the last two or three weeks, I’ve been sleeping pretty damn badly. Every morning, at around 5 or 6 A.M., I find myself awake, and usually, unable to get back to sleep. I have no idea what’s going on, but with final exams looming, this is about the worst time that this could have happened.

The result is that I am completely and utterly exhausted. I feel stressed and moody, and generally just lousy. I’m hoping this will clear up in a week or two, and when it does, I’ll be back writing again. Until then, I may publish one or two of the posts I wrote but never released.

Cartoon Me

Greg Williams, a cartoonist for the newspaper The Tampa Bay Observer, is certainly moving with the times. He draws a comic called Blogjam for the Observer based on blog posts from various sources. He took an interest in my long-ago post about the helium shortage, and turned it into a comic. The result? A delightfully-illustrated comic of the post, including a cartoon version of me!

Helium Shortage

You can see the comic here. And be sure to check out some of Williams’s other comics here. And I’m not just suggesting that because he drew me as flatteringly less scruffy than I actually look in real life, but because it’s actually an interesting and well-executed series he’s got going there.

10,000 Views!

I can’t believe it. It was only a few months ago that I was celebrating my 5,000th view. I guess my intuition was right, people are more interested in blogs that actually talk about something interesting, rather than just blathering on about the weather. You’d think I would have figured that out before now.

Anyway, in celebration of my 10,000th view, I give you: every number less than or equal to 10,000, with the primes highlighted. Yes, I know I’ve done an image like this before, but I thought it would be fitting.

Many thanks to all of my 10,000 readers thus far, and thanks especially those of you who were nice enough to leave all those encouraging comments!

And here’s hoping for another 10,000!

Visual Numbers #2

Factors: The numbers from 1 to 500 are plotted horizontally across the top row. Along each vertical column, if N divides the number X (represented here by distance across the top row) evenly (that is, if N is a factor of X), then the pixel N pixels down from the top is black.

Prime Factors: The same general principle as above, but in this image, only the prime factors are shown.

Blue Over Yellow: Basically, a combination of the previous two images. Numbers from 1 to 250 are plotted horizontally, and factors are plotted vertically. If a factor is prime, the little square representing it is blue, otherwise, it’s yellow.

That tantalizing structure is still just slightly out of reach…Oh well, back to work!

Visual Numbers #1

This is the beginning of what I hope will be a fairly long-running series of posts, each containing one or two (or three, if I’m feeling adventurous) numerical or mathematical visualizations. If you need a concrete example of what I’m talking about, just check out the image here).

Anyway, here goes:

Meet the Primes: Every pixel represents a number from 1 to 250,000. The image wraps horizontally; that is, the first pixel of the first row is the number 1, the first pixel of the second row is 501 (since each row is 500 pixels wide), the first pixel of the third row is 101, and so on and so on. Pixels representing prime numbers are black. From this view, it’s quite obvious that there’s likely some sort of structure to the primes, but it’s hard to say what that structure might be.

A Labor of Love

A few days ago, I was mucking about in the vast swampland that the Internet has become, and I stumbled upon yet another reference to a programming language I’d heard about a few times before: “Processing.” My interest piqued, I went in search of a compiler, and found one at Processing’s website (www.processing.org), and immediately started learning the language.

Given my many previous failures trying to learn Java, upon which Processing is based, I didn’t think I’d have much chance of learning the language, but I tried anyway, and actually found it just about as intuitive and elegant as Python, which remains my favorite programming language of all times. For a while, I cobbled together various tiny programs to do things like graph functions in one and two variables, graph parametric equations by replacing x, y, and z with rgb color values (producing a rather strange-looking wave of color that wasn’t nearly as interesting as I’d hoped), and visualizing one-dimensional celluar automata (which, by the way, was a complete failure, because Python is the only language I’ve found whose array-handling I can both tolerate and understand). Then, since I’m always a mathematician at heart, I thought I’d do something that mathematicians love to do: visualize the primes.

Before I go on, I should re-iterate just how much of a godsend Processing is. I’ve been trying to write methods in Python to visualize various kinds of functions and data for many moons, and my results have never been much more than mediocre. The only graphics module I’ve learned in Python (Tkinter, in case you were interested) is clumsy and runs slowly, and really isn’t meant to handle the kind of pixel-by-pixel manipulations I’d had in mind. Processing, though, exists solely for this purpose, which is the reason for my gushing for the last three paragraphs.

Anyway, the primes. I put together a simple program that computes the gap between the current prime number and the last prime number (using the standard Sieve of Eratosthenes method), and draws a circle at the location of the current prime whose size is based on the gap between the two primes.

I suspect I could have saved these thousand words by doing as the cliché says, and just giving you the picture:

Prime Gaps

(You can see a higher-resolution version here).

There’s a great deal of hidden beauty in this picture, most of which I can’t claim responsibility for. There’s a certain order to it, even though the primes seem to be quite random. Really, the beauty comes from the delicate, elegant structure of mathematics. The structure of the primes, as the structure of pi, is an expression of the deep structure of numbers, and thus, of the deep structure of the universe itself. It can be an almost religious experience, a sort of holy communion with the Numbers, to be given a glimpse of that structure.

I don’t know why I’ve been so sentimental lately…either way, the point I’m driving at is this: visualization is a really powerful tool for understanding mathematics. And Processing is a great programming language for visualization. (And, once again, I sound like I’m on somebody’s payroll, but I’m not. As far as you know.).

“Vantage Point”

Ever since I moved out, my father, apparently afflicted by some sort of empty-nest syndrome, has suggested that we go see a movie nearly every weekend. I can’t fault him for it, though, since it’s given me an opportunity to hone my review skills. An unfortunate side-effect of this, however, is the fact that I have to see contemporary movies, which are, almost entirely, cliché-riddled retreads (or outright remakes) of old storylines, with one-dimensional characters and atrocious dialogue apparently inspired by a 1990’s soap opera.

Pete Travis’s Vantage Point, however, is not such a film.

Vantage Point follows…actually…I can’t use my standard “follows the adventures of grizzled action hero X” here, since it doesn’t actually follow anyone in particular. More on that later. But basically, the plot of the film is thus: the president is speaking at some sort of anti-terrorism summit, and an assassination attempt is made, then the summit is bombed. But then, the audience finds out that it goes much deeper than that, but I wont’ spoil the rest.

This is one of those rare films that’s built around a concept. This is quite refreshing, since I haven’t seen a concept film in at least a decade. Most of the films I’ve seen of late have been character-based (which, don’t get me wrong, is probably the best way to tell a story) or based on nothing in particular (such as, say, any movie with Resident Evil in the title). But Vantage Point is based more around the idea of slowly assembling the plot by showing it through the viewpoint of five or six different people. Not an idea that’s been used very often.

Now, I must admit, I wasn’t expecting much. This kind of film is usually little more than an interesting experiment. Telling a story this way is also horrendously complicated, and I have a very low opinion of the ability of most modern directors to handle complicated stories. So I was incredibly surprised when I watched Vantage Point. It was actually good.

Its major saving grace is the novel way of telling the story: basically, you see one person’s view of the assassination attempt, the bombing, et cetera, then you jump back in time to the original starting point, and get to see those same events through the eyes of another character. Although this sounds like an idea that would have been done to death by now, it hasn’t been, and is fresh enough that what would have been a fairly boring action-movie plot is transformed into something quite fresh and engaging. There were times, such as a car-chase sequence, when I actually found myself on the edge of my seat. I haven’t been excited by a movie since I saw Twister as a child in 1996, but the continual jumps don’t give you a chance to get used to, or worse, get bored with, the action.

The other thing that surprised me about Vantage Point was the maturity of the plot. Of course, any action movie is bound to have a juvenile flavor to it, but this movie overcomes that by trying its hardest to feel genuine and to really say something. I’ve seen a few movies which try to cope with the idea of terrorism, but this is one of the few that I’ve seen that actually tries to say something about the politics of it, which is a nice change. And it helps the maturity factor a great deal that the characters aren’t so much cardboard cutouts. As you might expect, a film like Vantage Point, which basically has to be five or six mini-films, doesn’t have much time for character development, but it manages this quite competently nonetheless, using clean, concise exposition.

All that said, this is not a perfect movie. While the film’s multiple-viewpoint concept is interesting and refreshing, it really feels like a great deal was sacrificed for its sake, leading to some really contrived plot segments that annoyed me a great deal. You’ve heard of deus ex machina, that horrible “storytelling” technique where something unlikely appears at the last second to save a dying character or pull the storyline back together? Well, Vantage Point is guilty of using deus ex machina‘s dark cousin, deus ex technologica. I won’t give anything away, but suffice to say, one of the terrorists does more with a high-tech little cell phone than I ever knew was possible. For example, I searched my own phone’s menus for hours after the movie, looking for the “fire a sniper rifle”,” detonate a bomb”, and “make the plot make sense” buttons I saw the head terrorist use. After accidentally deleting most of my contact numbers, it dawned on me that the mutant phone-gadget-thing was no more than a way to neatly tie up the dozen or so loose ends that are the inevitable product of trying to do a story like this.

Even so, it’s an interesting movie, and entertaining, and the concept it revolves around is well-executed enough that it feels quite fresh. Even with the magic phones and the “shell-shocked old-time secret service agent” bit, it still comes together well enough that it’s worth seeing. Hell, it might even be worth it to see this one on the big screen.

Final Judgment:

* * * * * * * ` ~ ~ (7.5/10 asterisks)