# Number of Connections in the Brain

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I recently heard someone giving a speech on the brain and they said 'there are more connections in the brain than atoms in the universe'. I started to think about it and i can't get my head around it becasue surely for a connection at the very least 2 atoms are needed, therefore there can't be more connections than half the number of atoms in the brain.

Anyone know if what he said was true or is he speaking crap??

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I recently heard someone giving a speech on the brain and they said 'there are more connections in the brain than atoms in the universe'. I started to think about it and i can't get my head around it becasue surely for a connection at the very least 2 atoms are needed' date=' therefore there can't be more connections than half the number of atoms in the brain.

Anyone know if what he said was true or is he speaking crap??[/quote']

I'm not shure is its that many bit its a huge number I know that.

I think the number of atoms in the universe is approximated to be between $10^{81}$ and $10^{85}$ and the number of connections in the brain is about 100 trillion...

I could be wrong but thats what I remember reading

Cheers,

Ryan Jones

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wow, i still don't really understand how thats possible though

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Anyone know if what he said was true or is he speaking crap??

*cough*BULLSHIT*cough*

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wow, i still don't really understand how thats possible though

Well when you think abut it, it is logical

You conider how small a connection is and how many neurons there are in a brain and you get some idea of how its possible

Also don't forget that one neuron can have multiple connections - thats another reason for the large numbers and if you also consider the ammount your brain can store (hink about it and it will amaze you ) then you'll see its true

Edit: The number of connections in the numan brain is about $10^{14}$ according to my encyclopedia: Thats amazing when there are only about $10^{14}$ cells in the human body!

Cheers,

Ryan Jones

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A recent paper states that the numbers are:

"hundred billion (10^11) neurons and several hundred trillion synaptic connections"

The storage capacity is said to be 10^20 bits.

I think the actual number of connections at any one time is less than the number of atoms in the universe but the potential number of connections is higher than the number atoms in the universe.

Capacity limits of information processing in the brain. Marois R, Ivanoff J. Trends Cogn Sci. 2005 Jun;9(6):296-305.

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The neuron connections or synapses are composed of membrane, proteins, ions and transmitters, each of which are composed on many atoms. The number of connections can not be more than the number of atoms within the brain since each connections requires many atoms to set up the connection. At the same time, the whole neuron is not involved in connections, nor is anything within the neuron directly connected. Also all the water and any nonconducting cells, like blood, add more atoms to the brain's total. As a rough guess the number of neural connections might be something like 1/10,000 of the number of atoms in the brain. That is just a rough guess.

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The neuron connections or synapses are composed of membrane, proteins, ions and transmitters, each of which are composed on many atoms. The number of connections can not be more than the number of atoms within the brain since each connections requires many atoms to set up the connection. At the same time, the whole neuron is not involved in connections, nor is anything within the neuron directly connected. Also all the water and any nonconducting cells, like blood, add more atoms to the brain's total. As a rough guess the number of neural connections might be something like 1/10,000 of the number of atoms in the brain. That is just a rough guess.

Yup true.

The number of possible combinations though is another matter and far surpasses the number of atoms in the universe by well... a long way I'd think

Cheers,

Ryan Jones

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I guess if one looks at all the possible combinations of synapses in pairs of 2,4,8, etc., there are almost endless possibilities. But if one looks at neurons as dipoles, axum and dendrites, where signals move from higher to lower potential, it places a limit on the types and numbers of connections that can form. Some axums flow into the body from the brain implying their being at lower potential. The brain, itself is probably set up as a gradient of sorts, with the center of the brain being at a different potential than the cerebral. This would help create a hierarchy of memory rather than random memory storage. This would narrow possible connections with the goal of minimzation of brain potential.

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Theoretically, if we took all the atoms in the universe; wouldn't that include the atoms within the brain?

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Theoretically, if we took all the atoms in the universe; wouldn't that include the atoms within the brain?

Yes it would unless you lived outside the universe

Cheers,

Ryan Jones

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Maybe he meant the amount of ways they can connect...

meaning like since we have 100 billion neurons you can do 100 billion ^100 billion... which is a pretty darn big number

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Maybe he meant the amount of ways they can connect...

meaning like since we have 100 billion neurons you can do 100 billion ^100 billion... which is a pretty darn big number

Cheers,

Ryan Jones

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I know.... To who are you refering?

I responded to : aj47

I recently heard someone giving a speech on the brain and they said 'there are more connections in the brain than atoms in the universe'. I started to think about it and i can't get my head around it becasue surely for a connection at the very least 2 atoms are needed, therefore there can't be more connections than half the number of atoms in the brain.

Anyone know if what he said was true or is he speaking crap??

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The average number of connections in the human brain does not exceed the amount of atoms in the universe. If we assume that each connection is made of a dendrite/axon connection, then each connection requires many atoms. Therefore, if each connection requires many atoms, it is impossible that the connections could exceed the number of atoms in the universe.

Furthermore, the amount of potential connections could not exceed the amount of atoms in the universe. If each connection requires at least two atoms (they really require more) then the amount of connections in the brain could not possibly be more than 1/2 the amount of atoms in the universe. Obviously the brain could not have anywhere near this amount of connections because a human skull could not contain half the mass of the universe.

I'm guessing that when people use the term "potential connections" they are referring to the amount of possible different connections that could be made. If there are 10^11 neurons and each one can make 100 connections then the total possible number of different connections is 10^13 times 10^13, which is only 10^26 and much smaller than the estimated 10^80 or so atoms in the universe. Note that I don't know the average number of connections that each neuron makes, but it would have to be a very large number for the amount of possible connections to equal the amount of atoms in the universe.

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with out doubt, thats guy is talk crap

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the number of conections can not obviously be more than even the number of atoms in the brain. but if each conection can have at least two posible states to be in, say on or off, then the number of different configurations, possible combinations of on's and off's is some hugh number like 100 trilion squared or factoral or something much bigger than my brain could ever understand.

if each possible conection patern is concidered a "brain State" then brain states is probably what the original speaker ment to say.

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the number of conections can not obviously be more than even the number of atoms in the brain. but if each conection can have at least two posible states to be in' date=' say on or off, then the number of different configurations, possible combinations of on's and off's is some hugh number like 100 trilion squared or factoral or something much bigger than my brain could ever understand.

if each possible conection patern is concidered a "brain State" then brain states is probably what the original speaker ment to say.[/quote']

True, true. If I knew exactly how many connections each neuron could form it would be possible to calculate the number of possible pathways.

No-on happens to know the maximum number do they...

Actually I think we can work it out!

The brain has $10^{11}$ neurons in the brain, let this be $X_1$.

The brain has $10^{14}$ connections in the brain, let this be $X_2$.

$Max = X_2 / X_1$

$Max = 10^{14} / 10^{11}$

$Max = 10^{(14-11)}$

$Max = 10^{3}$ connections per neuron on average.

Which I think is.... $10^{3} * 10^{11}$

So the max possible number of connections = ${(10^{14})}^2$

Which is... $10^{28}$

If all those numbers are crrect then thats about right.

Cheers,

Ryan Jones

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Hmm well you seem to be having a point there

anyway check out this site on neuronal transmission animation

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Hi, The official number of neurons in the brain range between 10 and 100 billion neuron. Let's suppose, for argument's sake, every human being has precisely 100 billion neurons. The average number of connections for each neuron is about 10.000. So that would add up to 10^15 at most.

But I heard the original comment also before (which is ofcourse bullshit), but what was actually meant, if I remember correctly (and I have a phenomenal memory, since I have 10^15 connections to use for it...), is that not only the direct connections were meant, but all possible ways from each to any other neuron in the brain. And that is a lot more than 10^15. So, I agree with RyanJ

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sorry to say, but the brain doesnt have enough connection, pathways "brain states" or anything of that nature to come even close to the number of atoms in the universe. Maybe something like the number of galaxy's or something like that.

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sorry to say, but the brain doesnt have enough connection, pathways "brain states" or anything of that nature to come even close to the number of atoms in the universe. Maybe something like the number of galaxy's or something like that.

No-one said it did, I said 10^28 for my estimate based on the calculations a few posts back, Its probably a little bigger than that though based on the actual books I have read but thats a good enough estimate as far as I cna tell.

I don't know exactly the number fo galaxy's but there we go I probably agree with you on that one

Cheers,

Ryan Jones

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I was pretty much replying to the original post

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I was pretty much replying to the original post

OOPs, sorry

I do agree with you though, I'll be able to give more info when I find a rough estimate for the number of galaxy's in the universe

Cheers,

Ryan Jones

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A recent paper on this subject is Discovering the Capacity of Human Memory, Wang, et al, 2003, Brain and Mind, vol 4, no 2, p. 189-198.

The authors estimate the human brain's memory capacity at 10^8432 bits (yes, that's no typo).

Their basis for this: each possible neural connection path constitutes a memory bit. Once a given pathway is activated, a persistent change is somehow made such that re-activation triggers recalls the memory element (bit?). Thus the maximum capacity is given by the total possible number of connection paths.

Estimates of # neurons vary from about 100 to 500 billion. The average number of synapses per neuron vary from about 3,000 to 7,000. Each possible pathway from any synapse to any other synapse in the brain constitutes a potential unique memory element. The formula for calculating this is simple -- just calculate the number of combinations. We'll conservatively assume 100 billion neurons of 3,000 synapses each:

connection possibilities (unique pathways) = n! / m! * (n - m)!, where

n = number of neurons

m = average # of connections between neurons

= 10^11! / 3000! * (10^11 - 3000)!

It takes a special program to calculate such large factorials, but the result is 10^8432.

While I agree that number of potential neural paths exist, I'm not sure 10^8432 bits of storage is possible. The brain contains very roughly 10^26 atoms. Even if you assume each atom has six degrees of freedom, and that memory bits are stored on the atomic level, that's only about 10^27 bits.

Is there any way to store more data than you have equivalent storage bits? Is there any conceivable way the brain could store data more densely than the atomic level? If not, it would seem that 10^27 bits, not 10^8432 bits would form the maximum theoretical upper limit on memory capacity.

Would appreciate any comment on this, I've tried to figure it out but I'm stumped.

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