- there are 86 billion neurons in the human brain.
- a 5 byte address is large enough to reference 86 billion unique addresses -- one for each neuron
- each neuron has made an average of 1000 connections to other neurons
- each neuron has a weight. 1 byte can represent 256 different values. i *think* that's good enough precision.
86 billion neurons * ((5 byte address * 1000 connections on average) + 1 byte neuron weight)
=
5001 bytes * 86 billion neurons
=
43.0086 terabytes per brain
the current largest microSD cards are 2 terabytes and the companies that engineer them plan to reach 128tb before stopping. this is because they can't make the storage any bigger, due to expected physical engineering limits.
43.0086tb brain / 2tb sd card = 21.5043 of today's microSD cards to store a human brain
43.0086tb brain / 128tb sd card = 0.3360046875 of one future microSD card. 3 brains per card.
CONCLUSION: a brain can be stored much more compactly if it is stored digitally. this is probably because digital storage does not need to also have the ability to produce itself from nutrients. the task of producing the digital storage is instead left up to its manufacturing chain.
a common stat you'll hear is that the brain can hold 2.5 petabytes of data. however, in the Scientific American article this stat comes from, it's referring to the brain's capacity to store data that it compresses/deduplicates as it recieves it. let's fucking assume that 2.5pb is actually its raw data capacity.
2.5pb / 2tb = 1250 of today's microSD cards per brain
2.5pb / 128tb = 19.5 future microSD cards per brain
- a microSD card is 165mm^3 (0.165cm^3) in size
- a human brain is on average 1130 (female) to 1260 (male) cm^3 in size. let's go with the smaller, 1130cm^3 brain.
1250 of today's cards * 0.165cm^3 card size = 206.25cm^3, a digital brain approximately 1/5th of the size of the smaller female brain.
CONCLUSION (AGAIN): regardless of whether the brain is actually 2.5 petabytes of data, the human brain can be stored more compactly if it is stored digitally. this is probably for reasons mentioned in the last conclusion.
