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A Sixth Sense

June 17, 2011

Sometimes I feel like a stuck record, saying the same things over and over, but I want to spend a moment tonight reflecting on how amazing, and strange, consciousness really is.

Imagine if, while you were developing in the womb you underwent a mild complication leaving you with brain damage in your gustatory cortex.  You can find this area in the brain diagram below.

What would happen?  When you would go to eat, placing food in your mouth, you would feel it on your tongue and have a sensation of swallowing, but you would have no experience of taste.  You’d have no idea what “taste” even is.  You would eat food everyday and find it puzzling the hear your friends say, “Mmmm, this is delicious.”  You would have no idea what they’re talking about.  Why?  Those neurons in the gustatory cortex are responsible for producing a conscious sensation of taste.  When they fire in different patterns and different timings, you taste different things.  Considering that you wouldn’t have them, you’d have no experience of taste.  That’s weird, really weird.

There’s no analogy I can use which captures the mystery of our brains.  I’m going to write about neurons and how they function for my Space, Time, and the Mind “book”, considering they’re the underlying substrate for neural computation and the production of consciousness, but we can take a short look at them.  They’re cells like other cells within your body which have little gates and pumps in their cell walls, allowing them to move electrically charged ions in and out of them to produce electrical discharges which are sent down the neuronal axon to another neuron.  They call this an “action potential”.  To save myself some time, just watch this short video from Youtube.

The brain is filled with a salty fluid which has Calcium, Chlorine, Sodium and Potassium ions buzzing around.  To use a water analogy, when neurons conduct electrical current, they’re like leaky garden hoses.  It’s all a rather sloppy process.  I really like the animation in this next video.  These videos don’t show how messy it all is though.  When the electrical pulse is moving down the axon, there’s all kinds of leaking, which is why the signal needs to be continually amplified to make it any considerable distance.  You see that the axon is wrapped in myelin, which is basically like a duct tape for axons, but it doesn’t cover the entire axon.  You can easily see the gaps.  It helps stop a lot of the leaking, though it’s still really bad.

At the end of the axon you reach the synapse, which is the connector between one neuron and another. When the electrical pulse makes it here, various chemicals, called neurotransmitters, are released into an open gap called the synaptic cleft. Here the transmitters float down to the other end where they bind to various receptors, which then do things like stretch the cell membrane of the other neuron letting ions flow in. Here’s a video of the synaptic terminal.

Salt water pumps around in my head and releases various chemicals and voila, I have conscious experiences.  *Scratches head in amazement*  Why would salt water pumping around in my head produce consciousness?  My last post was about virtual reality.  I want to write an entire post about how that would work, but as for taste, I would only have to stick nanobots in your gustatory cortex and have them fire off your neurons based on signals I send them from a computer.  I could wirelessly communicate to them using say, radio waves.  I could then make you taste anything, even things you’ve never tasted before, even when nothing is in your mouth.

In your mouth there are tastebuds which undergo various chemical reactions with the food you eat, which then produce signals which are sent up to the brain in the gustatory cortex.  I’ll talk about all that in detail in my book.  In VR we just bypass these circuits and go straight to the cortex.

Ok, now that I’ve explained the basics as to what taste is (at least biologically), here’s a question I find myself pondering near every single day.  These neurons are pumping charged ions in salt water.  Let’s say I take my brain out my skull and put it in a jar.  I’m not an expert in biology, so I don’t know all the technicals as to how this would work exactly, but my DNA has instructions as to how to build more neurons.  Say I used my nanobots to initiate cell division processes in the brain and I grew new extra neurons and wired them up in new and novel patterns using my nanobots.  I start firing them in various patterns.  Could I generate a new sixth “sense”?  Instead of just being able to see, hear, taste, smell, and feel, could I also __ fill in the blank ___.  I have no idea what this new sense would be like and there’s certainly no way to put it into words.  But are there possibly an infinite number of new senses out there which we could wire ourselves up to experience?  Could I eventually become a being not just with five sense, but a thousand different senses?

Also, does consciousness need this rather sloppy medium of the brain to work?  Can I produce a conscious experience of tasting something by using more modern electrical equipment?  What if I build circuits that fire in the same sorts of ways as neurons but much more quickly?  Would I still taste?  I don’t know the answer to that but I really want to know.

When we look at each other, we see the light bouncing off their skin and clothing and only notice the body’s outer shell.  Our brain processes these light signals and we see images and perceive forms and their movements.  But what’s really inside people’s skulls?  This!

I don’t particularly find the brain aesthetically pleasing.  There’s all the hundreds of billions neurons with their ion pumps and channels moving electrical charge around producing your entire experience in this life.  Your memories, loves, hates, perceptions, bodily sensations — it all happens in there.

You know what gets me the most?  It’s all so fragile.  The only thing protecting your memories, bonds, knowledge, and everything you value most is a thin skull and a leather-like lining.  That’s not to say we can’t suffer from a stroke from eating greasy foods, plugging up our arteries and blocking blood flow to our brains.  The skull won’t help us there.  There’s no use belaboring that point.  Everyone knows that life is fragile.

Here’s a little thought experiment for you.  Say I filled a plastic pale with the same extra-cellular fluid which flows through the brain.  I then grow neurons in a lab and wire them up in various patterns, similar to the human brain, and place them in the pale.  I now send electrical pulses through them.  As long as I keep the neurons alive, and keep the pulses flowing, have I just created a conscious sentient being?  Is there someone living in there?  Would a conscious being, similar to myself, be experiencing a life, falling in love, working a job, and pondering the universe — all within the plastic pale?  Strangely, it also wouldn’t know it’s in a pale, but would think it’s someplace else.  That’s mind boggling.  Maybe we’re all living within an alien simulation in which they’re running a test to see how various patterns emerge based on a set of physical laws.

Commenting on my post Future Implications Of Virtual Reality, Tim asked if once we achieve full immersion VR, and we have the capability to experience anything we can currently imagine, is that the end?  Is there anything more?  Considering that we evolved from single-celled organisms which started sticking together into colonies, consciousness developed over time as nervous systems developed.  Assuming we augment additional neural circuitry into our brains, I think we may be able to add new senses, one by one, possibly indefinitely.  Just like the person who has never tasted before, maybe we’ll wire something up just right and be like, “Whooaaa, I’m experiencing something new!”  We’ll add a new sixth sense, and that should be interesting.   Our VR will initially be computers bringing us various patterns of experiences within five senses, but that may expand into new domains later on.  We’ll be fed combinations of experiences from twenty or thirty sensory modalities.

I also think physics will lead us into some new domains beyond what we currently think about.  There will be plenty to figure out, and even more to do!  I very much doubt there’s an end to the potential of what we can become.

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