Total Posts:12|Showing Posts:1-12
Jump to topic:

Neuron count for humans versus chimps

Wnope
Posts: 6,924
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 6:47:35 PM
Posted: 2 years ago
I've always believed that humans have disproportionately more neurons, relative to size, compared to other primates.

This may seem like the case since, relative to chimps, our brain has 2.5x the mass.

Turns out, interestingly, we only have 1.25x the neurons of a chimp, exactly what you predict by simply scaling up a chimp in size or scaling down a gorilla. Our "overdeveloped cortex" holds only 19% of the neurons in our brain.

The conclusion is that the primary difference in cognition between humans and chimps lies not in number of neurons but instead the connections between those neurons (where our increased brain mass comes from).

Rather interesting coincidence for Creationists. We get the evolutionaryily predicted neuron count instead of the disproportionate neural amount we might expect in a "unique" species.
Brain_crazy
Posts: 242
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 9:01:23 PM
Posted: 2 years ago
At 2/1/2012 6:47:35 PM, Wnope wrote:
I've always believed that humans have disproportionately more neurons, relative to size, compared to other primates.

This may seem like the case since, relative to chimps, our brain has 2.5x the mass.

Turns out, interestingly, we only have 1.25x the neurons of a chimp, exactly what you predict by simply scaling up a chimp in size or scaling down a gorilla. Our "overdeveloped cortex" holds only 19% of the neurons in our brain.

The conclusion is that the primary difference in cognition between humans and chimps lies not in number of neurons but instead the connections between those neurons (where our increased brain mass comes from).

Rather interesting coincidence for Creationists. We get the evolutionaryily predicted neuron count instead of the disproportionate neural amount we might expect in a "unique" species.

cool
Ren
Posts: 7,102
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 9:36:14 PM
Posted: 2 years ago
At 2/1/2012 6:47:35 PM, Wnope wrote:
I've always believed that humans have disproportionately more neurons, relative to size, compared to other primates.

This may seem like the case since, relative to chimps, our brain has 2.5x the mass.

Turns out, interestingly, we only have 1.25x the neurons of a chimp, exactly what you predict by simply scaling up a chimp in size or scaling down a gorilla. Our "overdeveloped cortex" holds only 19% of the neurons in our brain.

The conclusion is that the primary difference in cognition between humans and chimps lies not in number of neurons but instead the connections between those neurons (where our increased brain mass comes from).

Rather interesting coincidence for Creationists. We get the evolutionaryily predicted neuron count instead of the disproportionate neural amount we might expect in a "unique" species.

I found out about that relatively recently, too.

They're postulating that the major differences are still physiological, but in different ways. On one hand, there's the postulate that we have significantly more grey matter than do other primates. Another is precisely what you said -- the difference lay in the axions. They're considering that perhaps, whereas primates are running up to a Pentium I, we're somewhere a little further than an i7, maybe?

http://www.sciencedaily.com...

Apparently the quality of axions and their corresponding processing speed varies by human being, as well.

I wonder what processor I have running under the hood? ^_^
Ren
Posts: 7,102
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 9:38:19 PM
Posted: 2 years ago
On the other hand, there's also postulates that it's not physiological, but instead, genetically determined:

They discovered that the dysbindin-1 gene (DTNBP1), which they previously demonstrated to be associated with schizophrenia, may also be linked to general cognitive ability.

http://www.sciencedaily.com...

As always, it's likely a combination of most or all such aspects.
Brain_crazy
Posts: 242
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 9:47:31 PM
Posted: 2 years ago
At 2/1/2012 9:38:19 PM, Ren wrote:
On the other hand, there's also postulates that it's not physiological, but instead, genetically determined:

They discovered that the dysbindin-1 gene (DTNBP1), which they previously demonstrated to be associated with schizophrenia, may also be linked to general cognitive ability.

http://www.sciencedaily.com...

As always, it's likely a combination of most or all such aspects.

genetics ultimately map physiology... so I'm not sure what you're talking about.
Brain_crazy
Posts: 242
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 10:05:15 PM
Posted: 2 years ago
At 2/1/2012 9:36:14 PM, Ren wrote:
At 2/1/2012 6:47:35 PM, Wnope wrote:
I've always believed that humans have disproportionately more neurons, relative to size, compared to other primates.

This may seem like the case since, relative to chimps, our brain has 2.5x the mass.

Turns out, interestingly, we only have 1.25x the neurons of a chimp, exactly what you predict by simply scaling up a chimp in size or scaling down a gorilla. Our "overdeveloped cortex" holds only 19% of the neurons in our brain.

The conclusion is that the primary difference in cognition between humans and chimps lies not in number of neurons but instead the connections between those neurons (where our increased brain mass comes from).

Rather interesting coincidence for Creationists. We get the evolutionaryily predicted neuron count instead of the disproportionate neural amount we might expect in a "unique" species.

I found out about that relatively recently, too.

They're postulating that the major differences are still physiological, but in different ways. On one hand, there's the postulate that we have significantly more grey matter than do other primates. Another is precisely what you said -- the difference lay in the axions. They're considering that perhaps, whereas primates are running up to a Pentium I, we're somewhere a little further than an i7, maybe?

http://www.sciencedaily.com...

Apparently the quality of axions and their corresponding processing speed varies by human being, as well.

I wonder what processor I have running under the hood? ^_^

Ya its really interesting... how well myelinated are your axons? lol (at the same time though sometimes we can get too obsessive with these types of things)
Wnope
Posts: 6,924
Add as Friend
Challenge to a Debate
Send a Message
2/1/2012 10:47:26 PM
Posted: 2 years ago
At 2/1/2012 8:10:13 PM, UnStupendousMan wrote:
It's the connections in the brain that are important, not the size of the brain.

The mass of the brain is evidence of the extended connections. It's the space between neurons that are important.
Chthonian
Posts: 247
Add as Friend
Challenge to a Debate
Send a Message
2/2/2012 7:47:40 AM
Posted: 2 years ago
At 2/1/2012 9:47:31 PM, Brain_crazy wrote:
At 2/1/2012 9:38:19 PM, Ren wrote:
On the other hand, there's also postulates that it's not physiological, but instead, genetically determined:

They discovered that the dysbindin-1 gene (DTNBP1), which they previously demonstrated to be associated with schizophrenia, may also be linked to general cognitive ability.

http://www.sciencedaily.com...

As always, it's likely a combination of most or all such aspects.

genetics ultimately map physiology... so I'm not sure what you're talking about.

Here is an interesting piece of information:

There is apparently only a 1-2% nucleotide difference between chimps and humans, yet 80% of the proteins between these two primate species are different.

https://homes.bio.psu.edu...
Wnope
Posts: 6,924
Add as Friend
Challenge to a Debate
Send a Message
2/5/2012 5:11:23 PM
Posted: 2 years ago
At 2/2/2012 7:47:40 AM, Chthonian wrote:
At 2/1/2012 9:47:31 PM, Brain_crazy wrote:
At 2/1/2012 9:38:19 PM, Ren wrote:
On the other hand, there's also postulates that it's not physiological, but instead, genetically determined:

They discovered that the dysbindin-1 gene (DTNBP1), which they previously demonstrated to be associated with schizophrenia, may also be linked to general cognitive ability.

http://www.sciencedaily.com...

As always, it's likely a combination of most or all such aspects.

genetics ultimately map physiology... so I'm not sure what you're talking about.

Here is an interesting piece of information:

There is apparently only a 1-2% nucleotide difference between chimps and humans, yet 80% of the proteins between these two primate species are different.

https://homes.bio.psu.edu...

This may be mildly misleading.

When we say there is a 1-2% difference in nucleotides, this is clustered differently around the genome, but as the link notes, there is a random distribution of 0.6% nonynonymous subtitutions (changing one nucleotide for another which changes the amino acid sequence) across genes coding for proteins around 330 aminos long.

They only compare DNA sequences known to code for proteins, meaning it has to start with a certain DNA base pair and be followed by a substantial number of nucleotides. The paper defines two proteins as "different" is there is a single mismatch in amino acids.

So, they take around 140 proteins composed of long strings of nucleotides, each with a random distribution of 0.6% nucleotides for 330 bit strings which change the amino acid sequence (nonsynonymous).

If you look at the proteins they analyzed, the average length in nucleotides is...guess what? 350 bits.

Just by sheer statistical artifact, we would expect a majority of the 120 proteins to not match each other. Under this rubric, it's almost more surprising to find ANY matching proteins than 20%.

The median in the list of proteins which have identical nucleotides have lengths closer to 200 bits bits.
Mimshot
Posts: 275
Add as Friend
Challenge to a Debate
Send a Message
2/23/2012 12:15:08 PM
Posted: 2 years ago
There are also more neurons in your intestines than in your brain. What is your point exactly?
Mimshot: I support the 1956 Republican platform
DDMx: So, you're a socialist?
Mimshot: Yes
Wnope
Posts: 6,924
Add as Friend
Challenge to a Debate
Send a Message
2/23/2012 12:50:12 PM
Posted: 2 years ago
At 2/23/2012 12:15:08 PM, Mimshot wrote:
There are also more neurons in your intestines than in your brain. What is your point exactly?

It's been thought for some time that the increased brain mass for humans suggested disproportionate neural growth. That is, humans are special because we got an extra boost of neurons.

This shows that the neuron count of the human brain does not deviate from proportions we see in every other primate. Only brain mass deviates.