Why your brain is not a computer

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sciborg2

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« on: February 27, 2020, 08:46:11 pm »
Why your brain is not a computer

Matthew Cobb

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Reverse engineering a computer is often used as a thought experiment to show how, in principle, we might understand the brain. Inevitably, these thought experiments are successful, encouraging us to pursue this way of understanding the squishy organs in our heads. But in 2017, a pair of neuroscientists decided to actually do the experiment on a real computer chip, which had a real logic and real components with clearly designed functions. Things did not go as expected.

The duo – Eric Jonas and Konrad Paul Kording – employed the very techniques they normally used to analyse the brain and applied them to the MOS 6507 processor found in computers from the late 70s and early 80s that enabled those machines to run video games such as Donkey Kong and Space Invaders.

First, they obtained the connectome of the chip by scanning the 3510 enhancement-mode transistors it contained and simulating the device on a modern computer (including running the games programmes for 10 seconds). They then used the full range of neuroscientific techniques, such as “lesions” (removing transistors from the simulation), analysing the “spiking” activity of the virtual transistors and studying their connectivity, observing the effect of various manipulations on the behaviour of the system, as measured by its ability to launch each of the games.

Despite deploying this powerful analytical armoury, and despite the fact that there is a clear explanation for how the chip works (it has “ground truth”, in technospeak), the study failed to detect the hierarchy of information processing that occurs inside the chip. As Jonas and Kording put it, the techniques fell short of producing “a meaningful understanding”. Their conclusion was bleak: “Ultimately, the problem is not that neuroscientists could not understand a microprocessor, the problem is that they would not understand it given the approaches they are currently taking.”

This sobering outcome suggests that, despite the attractiveness of the computer metaphor and the fact that brains do indeed process information and somehow represent the external world, we still need to make significant theoretical breakthroughs in order to make progress.

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n reality, the very structures of a brain and a computer are completely different. In 2006, Larry Abbott wrote an essay titled “Where are the switches on this thing?”, in which he explored the potential biophysical bases of that most elementary component of an electronic device – a switch. Although inhibitory synapses can change the flow of activity by rendering a downstream neuron unresponsive, such interactions are relatively rare in the brain.

A neuron is not like a binary switch that can be turned on or off, forming a wiring diagram. Instead, neurons respond in an analogue way, changing their activity in response to changes in stimulation. The nervous system alters its working by changes in the patterns of activation in networks of cells composed of large numbers of units; it is these networks that channel, shift and shunt activity. Unlike any device we have yet envisaged, the nodes of these networks are not stable points like transistors or valves, but sets of neurons – hundreds, thousands, tens of thousands strong – that can respond consistently as a network over time, even if the component cells show inconsistent behaviour.

Understanding even the simplest of such networks is currently beyond our grasp. Eve Marder, a neuroscientist at Brandeis University, has spent much of her career trying to understand how a few dozen neurons in the lobster’s stomach produce a rhythmic grinding. Despite vast amounts of effort and ingenuity, we still cannot predict the effect of changing one component in this tiny network that is not even a simple brain.

This is the great problem we have to solve. On the one hand, brains are made of neurons and other cells, which interact together in networks, the activity of which is influenced not only by synaptic activity, but also by various factors such as neuromodulators. On the other hand, it is clear that brain function involves complex dynamic patterns of neuronal activity at a population level. Finding the link between these two levels of analysis will be a challenge for much of the rest of the century, I suspect. And the prospect of properly understanding what is happening in cases of mental illness is even further away.
« Last Edit: November 18, 2020, 04:53:02 pm by sciborg2 »

TaoHorror

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« Reply #1 on: February 28, 2020, 12:50:34 am »
What will happen if we make a breakthrough, I wonder ... if we do, then I think we'll be able to make a brain - will it be conscious ... interesting stuff, Sci
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sciborg2

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« Reply #2 on: February 28, 2020, 01:14:01 am »
What will happen if we make a breakthrough, I wonder ... if we do, then I think we'll be able to make a brain - will it be conscious ... interesting stuff, Sci

I think if we knew the relevant minimal structure and reproduced it in silicon it would be conscious.

That to me is different than a computer program running on Turing Machine suddenly making said machine conscious.

Wilshire

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« Reply #3 on: February 28, 2020, 01:05:16 pm »
Thats really interesting!

What will happen if we make a breakthrough, I wonder ... if we do, then I think we'll be able to make a brain - will it be conscious ... interesting stuff, Sci

I think if we knew the relevant minimal structure and reproduced it in silicon it would be conscious.

That to me is different than a computer program running on Turing Machine suddenly making said machine conscious.
That brings up several questions.

There are other things with complex brains, does that mean they could be (or are) conscious?
So do you think consciousness is the structure, or at least an inevitable outcome of the structure?
If consciousness spontaneously arose if we built something like that, "where" exactly is the consciousness?
One of the other conditions of possibility.

sciborg2

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« Reply #4 on: February 28, 2020, 10:03:44 pm »
That brings up several questions.

There are other things with complex brains, does that mean they could be (or are) conscious?
So do you think consciousness is the structure, or at least an inevitable outcome of the structure?
If consciousness spontaneously arose if we built something like that, "where" exactly is the consciousness?

"Did he have a soul Alfred? I think he did...A soul of silicon, but a soul nonetheless.."
 -Batman: TAS


Well admittedly it's a gamble, but I think it is a largely metaphysically neutral one? I mean it's possible we recreate the structures and nothing happens, the android or whatever just lies there un-ensouled.

But if it did emulate our own existence could we really deny its claim to sentience? I mean we can't even really locate consciousness in ourselves, as the brain - not to mention the body that houses it - are also within the phenomenal experience.

As to the question of structure's relevance, I suspect there's something very important about our own structure - after all why did our nervous system evolve if qualia didn't apply any evolutionary pressure/conditioning?

Admittedly we're seeing more & more that our mental nature is dependent on far more than the nervous system (for example gut bacteria) so it's possible that consciousness is inherent to biology in some way. It will be interesting if without that gut biome synthetic life is unbalanced in some way - conscious perhaps, but alien to us without these biological aspects of our bodies...[or maybe their consciousness is "better" than ours...]

"I'd heard it said that fairies have no souls."

"Then do I ache, and bleed, and smart, elsewhere; still, call it soul for it is solely mine."

 -Gaiman, World's End
« Last Edit: February 28, 2020, 10:05:15 pm by sciborg2 »

Wilshire

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« Reply #5 on: March 02, 2020, 03:25:36 pm »
I think human exceptionalism will beguile the study of consciousness, not only ourselves but especially in other things, for centuries.

It might be an insurmountable hurdle for human kind - we simply cannot exist the way we do today if we decide that things other than ourselves actually matter. We can't, in most cases, see other people as significant, let alone animals and computers.
One of the other conditions of possibility.

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« Reply #6 on: March 02, 2020, 03:56:24 pm »
I think human exceptionalism will beguile the study of consciousness, not only ourselves but especially in other things, for centuries.

It might be an insurmountable hurdle for human kind - we simply cannot exist the way we do today if we decide that things other than ourselves actually matter. We can't, in most cases, see other people as significant, let alone animals and computers.

I'd agree, although, it seems like a swing of the pendulum the other way is equally as problematic.  That is kind of a problem I personally feel when I read something about panpsychism or a really bare physicalism.  Then again, it might also just be mess missing the argument there as well.
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sciborg2

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« Reply #7 on: March 02, 2020, 08:23:52 pm »
Having a human faction dedicated to robot rights is just a pair of silicon globes away IMO...add a self-cleaning fleshlight and we may as well play it safe by bowing before Roko's Basilisk before it arrives.