Cells are basically tiny computers: They send and receive inputs and output accordingly. In the last couple of decades, biologists have been working to hack the cells’ algorithm in an effort to control their processes 1
"I regard the brain as a computer which will stop working when its components fail. 5
Biological Cells are sophisticated data and information processing machines 2
Your Cortex Contains 17 Billion Computers. Brains receive input from the outside world, their neurons do something to that input, and create an output. 3
Why does this local spike change the way we think about the brain as a computer? Because the dendrites of a pyramidal neuron contain many separate branches. And each can sum-up-and-spit-out-a-spike. Which means that each branch of a dendrite acts like a little nonlinear output device, summing up and outputting a local spike if that branch gets enough inputs at roughly the same time. The extraordinary implication of these local spikes is that each neuron is a computer. By itself the neuron can compute a huge range of so-called nonlinear functions. Functions that a neuron which just sums-up-and-spits-out-a-spike cannot ever compute. a single neuron can compute an amazing range of functions even if it cannot make a local, dendritic spike. Because dendrites are naturally not linear: in their normal state they actually sum up inputs to total less than the individual values. They are sub-linear. For them 2+2 = 3.5. And having many dendritic branches with sub-linear summation also lets the neuron act as two-layer neural network. A two-layer neural network that can compute a different set of non-linear functions to those computed by neurons with supra-linear dendrites. And pretty much every neuron in the brain has dendrites. So almost all neurons could, in principle, be a two-layer neural network.
The other amazing implication of the local spike is that neurons know a hell of a lot more about the world than they tell us — or other neurons, for that matter.
Yes, the brain is a computer…No, it’s not a metaphor 4
The brain is a computer, and neuroscience is also branch of computer science. If you understand the formal definitions of computer and algorithm as given by computer science, then you know that the brain is very clearly a computer running algorithms, almost trivially so.
The formal definition of computing is:
(1) an algorithm is anything a Turing machine can do,
(2) computable functions are defined as those functions that we have algorithms for,
(3) a computer is anything which physically implements algorithms in order to solve computable functions.
Brains are also “uber-computers”, they just work in a different manner. we can think of neural networks as a sort of programming language: the synaptic connections in a neural network define the functions that they implement, so the set of all possible neural network architectures is effectively a programming language, and this language is Turing complete. Although there are many differences between artificial neural networks and brains, arguably those differences only render real brains more computationally powerful than artificial neural networks. This means that when we consider the set of all possible brains, then for any given computable function, there is probably a hypothetical brain that can solve it. Thus, the “language of brains”, as it were, is probably Turing complete.
Given that the set of neural networks is Turing complete (and therefore also probably the set of possible brains), it is pretty clear that brains deserve the title “computer”. Therefore, the brain is a computer. It’s not a metaphor, it’s not an analogy, it’s a fact.
An 83,000-Processor Supercomputer Can Only Match 1% of Your Brain.
Taking advantage of the almost 83,000 processors of one of the world's most powerful supercomputers, the team was able to mimic just one percent of one second's worth of human brain activity—and even that took 40 minutes. 6
Computers collaborate in the Internet much the way cells collaborate in multicellular organisms and the way organisms compete and collaborate in ecologies. 7
The Geometric Structure of the Brain Fiber Pathways
Last edited by Otangelo on Sat Apr 30, 2022 2:48 pm; edited 3 times in total