Brain-Based Devices

From an interview with Gerald Edelman (h/t: Cosmic Variance):


How are you pursuing the creation of conscious artifacts in your work at the Neurosciences Institute?

We construct what we call brain-based devices, or BBDs, which will be increasingly useful in understanding how the brain works and modeling the brain. They may also be the beginning of the design of truly intelligent machines.

What exactly is a brain-based device?

It looks like maybe a robot, R2-D2 almost. But it isn’t a robot, because it’s not run by an artificial intelligence [AI] program of logic. It’s run by an artificial brain modeled on the vertebrate or mammalian brain. Where it differs from a real brain, aside from being simulated in a computer, is in the number of neurons. Compared with, let’s say, 30 billion neurons and a million billion connections in the human cortex alone, the most complex brain-based devices presently have less than a million neurons and maybe up to 10 million or so synapses, the space across which nerve impulses pass from one neuron to another.

What is interesting about BBDs is that they are embedded in and sample the real world. They have something that is equivalent to an eye: a camera. We give them microphones for the equivalent of ears. We have something that matches conductance for taste. These devices send inputs into the brain as if they were your tongue, your eyes, your ears. Our BBD called Darwin 7 can actually undergo conditioning. It can learn to pick up and “taste” blocks, which have patterns that can be identified as good-tasting or bad-tasting. It will stay away from the bad-tasting blocks, which have images of blobs instead of stripes on them —rather than pick them up and taste them. It learns to do that all on its own.

Why is this kind of machine better than a robot controlled by traditional artificial intelligence software?

An artificial intelligence program is algorithmic: You write a series of instructions that are based on conditionals, and you anticipate what the problems might be. AI robot soccer players make mistakes because you can’t possibly anticipate every possible scenario on a field. Instead of writing algorithms, we have our BBDs play sample games and learn, just the way you train your dog to do tricks.

At the invitation of the Defense Advanced Research Projects Agency, we incorporated a brain of the kind that we were just talking about into a Segway transporter. And we played a match of soccer against Carnegie Mellon University, which worked with an AI-based Segway. We won five games out of five. That’s because our device learned to pick up a ball and kick it back to a human colleague. It learned the colors of its teammates. It did not just execute algorithms.

It’s hard to comprehend what you are doing. What is the equivalent of a neuron in your brain-based device?

A biological neuron has a complex shape with a set of diverging branches, called dendrites, coming from one part of the center of the cell, and a very long single process called an axon. When you stimulate a neuron, ions like sodium and potassium and chloride flow back and forth, causing what’s called an action potential to travel down the neuron, through the axon, to a synapse. At the synapse, the neuron releases neurotransmitters that flow into another, postsynaptic neuron, which then fires too. In a BBD, we use a computer to simulate these properties, emulating everything that a real neuron does in a series of descriptions from a computer. We have a set of simple equations that describe neuron firing so well that even an expert can’t tell the difference between our simulation spikes and the real thing.

All these simulations and equations sound a lot like the artificial intelligence ideas that haven’t been very successful so far. How does your concept for a conscious artifact differ?

The brain can be simulated on a computer, but when you interface a BBD with the real world, it has the same old problem: The input is ambiguous and complex. What is the best way for the BBD to respond? Neural Darwinism explains how to solve the problem. On our computers we can trace all of the simulated neuronal connections during anything the BBD does. Every 200 milliseconds after the behavior, we ask: What was firing? What was connected? Using mathematical techniques we can actually see the whole thing converge to an output. Of course we are not working with a real brain, but it’s a hint as to what we might need to do to understand real brains.

When are we going to see the first conscious artifact emerge from your laboratory?

Eugene Izhikevitch [a mathematician at the Neurosciences Institute] and I have made a model with a million simulated neurons and almost half a billion synapses, all connected through neuronal anatomy equivalent to that of a cat brain. What we find, to our delight, is that it has intrinsic activity. Up until now our BBDs had activity only when they confronted the world, when they saw input signals. In between signals, they went dark. But this damn thing now fires on its own continually. The second thing is, it has beta waves and gamma waves just like the regular cortex—what you would see if you did an electroencephalogram. Third of all, it has a rest state. That is, when you don’t stimulate it, the whole population of neurons stray back and forth, as has been described by scientists in human beings who aren’t thinking of anything.

In other words, our device has some lovely properties that are necessary to the idea of a conscious artifact. It has that property of indwelling activity. So the brain is already speaking to itself. That’s a very important concept for consciousness.


15 thoughts on “Brain-Based Devices

  1. Nice. It makes evolutionary sense that complex brains would have been built up from fairly simple components, not unlike the ones used in these neural simulations — otherwise you’d need to invoke skyhooks. Likewise with learning: simple connections attuned to gross features serve as the foundation for both more fine-tuned and more global awareness, built up incrementally.

    “What is interesting about BBDs is that they are embedded in and sample the real world.”

    I suppose one could say that it’s cheating to equip the device with predesigned sensory apparati. But the point of these simulations isn’t to model how ears evolved — others are working on that question– but to figure out how auditory input gets used by brains. To “sample the real world” isn’t a claim that the Real is essentially sonic, I’m sure you’d agree.

  2. Kevin,

    Agreed, it’s an interesting phrase, rather well-suited to the idea at hand.


    Is skyhooks a technical term? I’m not familiar with it…

    You’re right though, that these sorts of systems would have to be produced – particularly in light of Edelman’s neural Darwinism! I’m sure other people have attempted that, but what I find really surprising and fascinating is the last portion, where he points out that these BBDs have a ‘rest state’ of brain activity. It’s as though it truly does have some minimal level of consciousness (or is at least making a significant step towards it).

    I’ll just add, it’s a non-proposition-based form of consciousness too!

  3. Nick,

    I’m sure that John will join in and explain, but as a side comment I love that you sense that “skyhook” is a technical phrase. It comes from Daniel Dennett and his algorithmic love for Darwin who he feels gives us a world description that needs no deus ex machina swooping down from above on a crane to explain how things came to be what they are. Dennett has a nice arsonal of these very interesting phrases, which are a kind of “technical” language which operates with rhetorical force, “folk psychology” is another successful one. They are meant to both delimit the kind of claim capable of being made, but also to gently ridicule the claims of others.

    I’m not saying that we need to seek “skyhook” type explanations, but I do find the rhetorical force of these terminologies interesting.

    • Yes, that’s the idea. Dennett contrasts the skyhook, which drops down from the sky, with the crane, which is a device that lifts things into the air from a base position on the ground. In Dennett’s evolutionary and rhetorical toolkit, skyhooks are bad while cranes are good.

  4. The construction of a neural simulation itself employs a cranelike operation, building more complex models on top of simpler predecessors. Exceeding certain limiting levels of scientific complexity requires some dismantling and reconstruction on a different scaffolding, not unlike the introduction of the flying buttress in architecture.

  5. John, much thanks as I did not make that clear at all. The implicit reference to the deus ex machina is of course that the “god” in the play is indeed come from a crane that is attached to the ground, while we theatrically, and imaginatively take him to “come from the sky”.

    I wonder though, this easy division between skyhooks and cranes – and I’m a big fan of Dennett – has perhaps some lasting epistemological ambiguities, for there are times when examining “cranes” that we have to take them as “skyhooks” so as to productively fiil out our maps of the world. And while one might assume that all “skyhooks” are really “cranes” our paths of knowledge may not be able to operate like this. How imaginary can our knowledge be is certainly an interesting question.

  6. Hmm, interesting stuff. Do either of you have a recommendation for where to start with Dennett? I’m particularly interested in his philosophy of mind stuff – is Consciousness Explained his best attempt at that? Or does he have newer stuff that rejects major aspects of that work?

    Thanks in advance!

    • Nick,

      I second Kvond’s suggestion of Darwin’s Dangerous Idea. That’s where you’ll find concepts like “skyhooks”. I’m much less keen on Consciousness Explained, perhaps I need to take a look at it once again as I haven’t cracked it for over a decade and philosophically I was in a very different place at that time. Although I have a number of problems with Dennett’s gene-centrism– siding more with Gould on these issues –it’s still a terrific book. I’m teaching it this fall.

  7. Skyhooks is an expression, I think mostly common in Australian English, referring to a machine or device intended to perform some impossible task. As in: “How’re they ever going to do that? Oh, they’ll just use skyhooks.” In the 1970s there was an Australian band called Skyhooks that were quite well known in their home country. A similar expression, referring to some inscrutable machine or tool is “wanking spanner” – it’s a pity Dennett didn’t take that one up as well.

  8. Do you have a block diagram of the software. Or , is it public domain? What if the average joe wanted to play with the whole concept of BBDs. Do you have to have a Beowulf setup or can you use something like a Basic StampII, Or Arduino? Or maybe a dual or quad core cpu setup. I would like to learn more to “play” with this concept in my own personal laboratory. I have got robots already. They can be programmed in Spin, Asm, Basic, Robot Basic, C++. Are there any starter programs I can download to get started?

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