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Comment by s-macke | Hacker News Reader

What is your guess about the amount of memory needed to save a human brain. I mean all necessary information to save the personality. The article mentions 98,000 petabytes. But does this contain everything?

In Wolfram alpha and Wikipedia you can read, that the storage capacity of the human brain is around 2-2.5PB.

When I estimate it assuming 10^14 synapses and 24 bytes (weight, connection info, etc.) for each synapse, I come close to 2PB.

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The article lists 1.8P for a brain with 75 million neurons. Unless I've misplaced my zeroes, that's over ~20M per neuron, which seems much higher than I'd expect.

A neuron is a lot more complicated than you would expect.

Well the article near the end says that the data for the experiment was 1.8 PB. I am not sure what the answer is, but given a mouse brain is significantly smaller than a human brain I would say Wolfram Alpha and Wikipedia are wrong.

I am not sure, but after looking at their sites they probably mean images. So, a synapse in a let's say high resolution jpeg will need much more memory than my abstract definition of a synapse.

i'm wondering if the massive amounts of Petabytes can be compressed in some efficient way. probably.

Well, of course. I would suggest paq8l ;)

I think you can store very efficiently. A neuron or synapse has a huge error rate. So, saving parameters of the synapse as 4 byte floating point number could be overkill. Connection information could be also reduced significantly by an intelligent sorting. E. g. you don't have to store the source index and neurons connect probably more to their neighbors then to neurons far away. Therefore I am wondering, what must be saved in 24 byte. Well, we will know, when we try it some day. At the moment it's just speculation.

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