Neurons: humans v. pigs, ants and worms...

Speakpigeon

Speakpigeon

Valued Senior Member
Do we know of any functional difference between the neurons of a human and the neurons of other species, say pigs, ants, and worms?
EB
 
I don't know of any differences. I'd expect mammals, at least, to all have essentially the same kinds of neurons. Not sure about ants and worms. But I haven't investigated.
 
Speakpigeon said:
Do we know of any functional difference between the neurons of a human and the neurons of other species, say pigs, ants, and worms?
EB
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Not really. All neurons do essentially the same thing regardless of whether it’s a worm or a human – propagate membrane potentials in order to produce a response in a connected cell(s). The connected cell(s) may be other neurons or may be effector cells (muscle, endocrine or other glands, skin, epithelial, endothelial, etc.).

The difference between a worm and a human is not the function of neurons but rather the number of neurons, the complexity of the neuronal network, and the repertoire of genes and receptors that they have to work with.
 
Hercules Rockefeller said:
Not really. All neurons do essentially the same thing regardless of whether it’s a worm or a human – propagate membrane potentials in order to produce a response in a connected cell(s). The connected cell(s) may be other neurons or may be effector cells (muscle, endocrine or other glands, skin, epithelial, endothelial, etc.).

The difference between a worm and a human is not the function of neurons but rather the number of neurons, the complexity of the neuronal network, and the repertoire of genes and receptors that they have to work with.
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Thanks, that is really interesting! Would you have any Internet reference about this point?

I take it that you know what you are talking about in this respect but I would rather not be limited to just quoting you!
EB
 
Just to add: I would expect the neurons of a worm, say, to be essentially the same as those of a human being, because after all we share a common ancestor, and neurons are common features of animals.
 
Speakpigeon said:
Would you have any Internet reference about this point?
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I did some quick literature digging. There is no end of info on the interweb on how neurons function. Here’s an edited extract from Wikipedia:
A neuron is an electrically excitable cell that communicates with other cells via specialized connections called synapses. A typical neuron consists of a cell body (soma), dendrites, and a single axon. Most neurons receive signals via the dendrites and soma and send out signals down the axon. The signaling process is partly electrical and partly chemical. Neurons are electrically excitable, due to maintenance of voltage gradients across their membranes. If the voltage changes by a large enough amount over a short interval, the neuron generates an all-or-nothing electrochemical pulse called an action potential. This potential travels rapidly along the axon, and activates synaptic connections as it reaches them. Synaptic signals may be excitatory or inhibitory, increasing or reducing the net voltage that reaches the soma.

https://en.wikipedia.org/wiki/Neuron
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The technical publication cited for this information is:
Neuronal excitability: voltage-dependent currents and synaptic transmission.
Rutecki PA.
J Clin Neurophysiol. 1992 Apr;9(2):195-211.
https://www.ncbi.nlm.nih.gov/pubmed/1375602​

This basic cellular process is universal across all animals. I previously said there was no functional difference between invertebrate and vertebrate neurons. Upon further inspection, this isn’t quite true. There is a rule that impulses propagate from dendrite to axon according to a law of dynamic polarization (Cajal, 1891). This rule holds for most neurons in the vertebrate brain, except notably the retina, but is widely violated in invertebrate brains. I imagine this is because invertebrate neurites form both pre- and post-synaptic contacts which don’t occur in vertebrates (post-synaptic neurites and pre-synaptic axons).

This seems to be quite a good non-technical comparison between vertebrate and invertebrate nervous systems.

I found these comprehensive technical reviews of invertebrate neuronal biology:

Having quickly scanned through them, they confirm that the difference between vertebrate and invertebrate nervous systems is not the basic cellular functioning of neurons, but rather the number of neurons, the number of connections, myelination, neurotransmitters, neuronal circuitry and the architecture of nervous system structures.
 
And microtubules......:)

They make up the interior of neurons and are the micro-computers that make all neural activity possible.

Microtubules are shared by all eukariotic organisms from single celled parameciums to whales.
Microtubules.jpg

Microtubules are small tubes formed by thirteen filamentous strands. Each filament is composed of a chain of protein called tubulin. Microtubules in a neuron are used to transport substances to different parts of the cell. For example, neurotransmitters are made in the cell body close to the nucleus, but need to travel long distances to the end of axons where they will be used for synaptic transmission. Microtubules are the route via which these essential molecules are transported from the site of synthesis to where they are needed.
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https://psych.athabascau.ca/html/Psych402/Biotutorials/1/microtubules.shtml
Are Microtubules the Brain of the Neuron
November 29, 2015
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http://jonlieffmd.com/blog/are-microtubules-the-brain-of-the-neuron
 
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James R said:
Just to add: I would expect the neurons of a worm, say, to be essentially the same as those of a human being, because after all we share a common ancestor, and neurons are common features of animals.
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Sure but the question is whether neurons have evolved between the first worms and us humans now enough to make our neurons functionally different. Another way to say it to ask whether the main difference between the human brain the few neurons of a worm comes from the size of our brain, and the differentiation in the role played by different neurons allowed by the large number of neurons we have. Compare with human societies: same basic human beings everywhere but all potentially playing different roles because there are several layers of organisation between the individual and society as a whole. Our neurons might be like that. Essentially all the same and the same as those of a worm but playing different roles in our big brain whereas they probably all play the same role in a worm.
EB
 
Speakpigeon said:
Sure but the question is whether neurons have evolved between the first worms and us humans now enough to make our neurons functionally different. Another way to say it to ask whether the main difference between the human brain the few neurons of a worm comes from the size of our brain, and the differentiation in the role played by different neurons allowed by the large number of neurons we have. Compare with human societies: same basic human beings everywhere but all potentially playing different roles because there are several layers of organisation between the individual and society as a whole. Our neurons might be like that. Essentially all the same and the same as those of a worm but playing different roles in our big brain whereas they probably all play the same role in a worm.
EB
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If I am correct neurons store and transmit information. I am unsure if the neurons of a human and neurons of a worm are functionally different, I think it was said they are structurally the same, or similar, because the human brain has more intelligence and has more capacity than a worm's brain does, or if the two organisms' neurons function in the same way, but are just interconnected in different and more numerous ways, so as to function differently as a whole.
 
mmatt9876 said:
I think it was said they are structurally the same, or similar, because the human brain has more intelligence and has more capacity than a worm's brain does, or if the two organisms' neurons function in the same way, but are just interconnected in different and more numerous ways, so as to function differently as a whole.
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The difference is between a few thousand neurons in a worm or a single cell and a trillion neurons in humans. But more importantly, the processing power of neurons lies in the number of microtubules.

The proof that more neurons create greater intelligence lies in the remarkable abilities of the SINGLE CELLED slime-mold. It has no neurons, but the cell itself contains many microtubules which give the slime mold some extraordinary computational abilities, such as memory of time intervals, memory of previously visited areas, and above all a extra ordinary ability for movement and exploration via a fractal dynamic.
physar1b.jpg
An image of "quorum sensing" by a multi-nucleic single celled organism
https://www2.palomar.edu/users/warmstrong/slime1.htm


Is this a form of intelligence? It behaves in an intelligent manner, no?

 
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exchemist said:
BINGO!
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Did you read the link?
Did you read how these medicines function; Albendazole and Mebendazole
Albendazole and mebendazole work by preventing synthesis of microtubules in the worms, blocking the ability of worms to shuttle proteins through their cells.
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https://www.livestrong.com/article/216236-medications-to-treat-human-worms/

Perhaps you refuse to accept the fact that microtubules are the information carriers in neurons in every eukaryotic organism, from single cells to mammals.

When microtubules are blocked from shuttling proteins (information) through worm cells, the organism becomes functionally impaired.
 
Write4U said:
Did you read the link?
Did you read how these medicines function; Albendazole and Mebendazole

https://www.livestrong.com/article/216236-medications-to-treat-human-worms/

Perhaps you refuse to accept the fact that microtubules are the information carriers in neurons in every eukaryotic organism, from single cells to mammals.

When microtubules are blocked from shuttling proteins (information) through worm cells, the organism becomes functionally impaired.
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BINGO!
 
exchemist said:
BINGO!
Click to expand...
Albendazole and mebendazole work by preventing synthesis of microtubules in the worms, blocking the ability of worms to shuttle proteins through their cells.

This is an answer to the question. Can anyone do better than "microtubules"? OK out with it.
 
Speakpigeon said:
Do we know of any functional difference between the neurons of a human and the neurons of other species, say pigs, ants, and worms?
EB
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It don't know of any gross difference in neuron cell anatomy between the animal phyla and taxa. There do seem to be some differences in the precise chemical details on the synaptic cell membranes. But I'm ignorant of the details. In particular, I don't know how significant these differences are or whether they impact function. Even in that regard, I wouldn't expect a whole lot of difference between humans and other mammals, particularly hominids.

To investigate this, perhaps the place to look is the literature on the evolution of neurons.

Here's a survey published by the US National Academies of Science that addresses it in detail (I haven't really read it, just skimmed through the relevant chapters):

The preface is interesting, about what Charles Darwin and Thomas Huxley thought about this

https://www.nap.edu/read/13462/chapter/1#xv

This chapter is a summary of what's to come

https://www.nap.edu/read/13462/chapter/2

This chapter discusses the genes and gene networks that are mobilized to produce neurons and synapses, and how these functional networks may have originated. It seems that many of the genes were already there in earlier prokaryotes, making pores in cell membranes and stuff. What got specialized neurons up and running may have been changes in how those genes were regulated, so that they behaved together in functional groups. This chapter is about that:

https://www.nap.edu/read/13462/chapter/3

This chapter discusses the evolution of voltage-gated sodium channels (the business end of synapses). There do seem to be some differences between evolutionary lineages, but not always to our mammalian advantage. It seems that other lineages may have some pathways we don't and might (arguably) have more advanced neurons. (Again, the problem regarding function.)

https://www.nap.edu/read/13462/chapter/4#22

And this chapter discusses the evolution of central nervous systems.

https://www.nap.edu/read/13462/chapter/5
 
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Write4U said:
And microtubules......:)
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I realize that you are enthusiastic, W4U. But sometimes this stuff starts to look like an obsession. I wish that you wouldn't try to take over threads and drown everyone else out with it. It isn't helpful.
 
In post #16 I wrote: "It seems that many of the genes were already there in earlier prokaryotes, making pores in cell membranes and stuff."

That should read 'eukaryotes'. Protozoa and whatnot that existed before the appearance of the first multicellular organisms.

I was going too fast and not paying attention. It might be true of prokaryotes too, but I don't know that.
 
Yazata said:
I realize that you are enthusiastic, W4U. But sometimes this stuff starts to look like an obsession. I wish that you wouldn't try to take over threads and drown everyone else out with it. It isn't helpful.
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I am really astounded by the resistance to new and pertinent information about neural properties and activities, and the role microtubules play in the processing of information essential to life.
Have you looked at schematic of a neuron? Have you read anything at all about microtubules? Seems to me that if you want to discuss neurons , you may want to start with microtubules. In describing an electric cord, we do not talk about the rubber covering but about the guage of the copper wire inside the cord. When talking about neurons (in context of information processing and transmission, you don't want to talk about the axon, you want to talk about the microtubules inside the axon.
Axon, also called nerve fibre, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon that connects it with other neurons or with muscle or gland cells. Some axons may be quite long, reaching, for example, from the spinal cord down to a toe.
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https://www.britannica.com/science/axon

Just like a long extension cord of unknown guage.

It isn't helpful? With the exception of a few statements of fact by others, I am the only one to posit anything of substance in reply to the OP question. Will someone please read what I post or link. Trust me, you will be enlightened and delighted as I was when learning something new about the processes which keep humans and other organisms alive at nano scale.
If I seem obsessed it is because it is true and replaces the old school of thinking in this area. Dare to explore, Yazata. I guarantee it'll be worth your while.

We are talking about the nature and composition of neurons and if neurons in various organisms have common denominators.
One common denominator of neurons is that they all have the same microtubules for processing informational values at nano scale and which may well be the elusive quantum computer of most living eukaryotic organisms. It is a very simple self-assembling bi-directional information processor, but they exist in our body by the trillions. A computer network in a three pound fatty organ, which puts most supercomputers to shame.

Microtubules are the computing part of neurons and are present as a common denominator in neurons.
Neurons themselves are cells and consist of several other non-computing parts. Shown above in post #8

The neural function of processing and transmission of information is determined by the microtubules inside the neurons. That's where the answers lie.

IMO this NEW FIELD of insight is extremely important in studying the components and functions of neurons.
The microtubule cytoskeleton is essential for a wide variety of cellular functions, such as chromosome segregation, directed vesicle and organelle transport, cell motility and cell polarity. Impaired microtubule function can lead to human diseases including cancer and neurodegenerative disorders. In recent years, interdisciplinary approaches embracing cell biology, genetics, molecular biology, biochemistry, biophysics, structural biology and mathematical modelling have made a tremendous impact on the microtubule field.
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https://www.embo-embl-symposia.org/...MImPLcquWZ5QIVph6tBh3s1wVxEAAYASAAEgJmm_D_BwE

The lack of interest at cutting edge science is disappointing. Moreover the actual resistance to learning something new is revealing of the caliber discussion on this subject. No one shows any in depth knowledge of neurons at all.
Yazata said:
To investigate this, perhaps the place to look is the literature on the evolution of neurons
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That's what I have been trying to do, but everybody complains about obsessive behavior...??????
 
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Yazata said,
And this chapter discusses the evolution of central nervous systems.

https://www.nap.edu/read/13462/chapter/5
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It describes nervous systems, not what does the computation inside a neuron .

If you want to see the microtubule network here are examples.
Mitochondria-cytoplasm-cells.jpg

Microtubules (shown in green) play an important role in cytoplasmic streaming.

https://www.britannica.com/science/cell-biology/Cell-division-and-growth#ref37456

@ exchemist,
Note the overwhelming presence of microtubules which are so small as to escape most illustrations of neurons.
But it is the marked green stuff what does the computational work and suggests being the seat of conscious sentience.
th
Summary:
Images of microtubule assembly and disassembly have been produced by researchers at the unprecedented resolution of 5 angstroms, providing new insight into the success of the anti-cancer drug Taxol and pointing the way to possible improvements. "This is the first experimental demonstration of the link between nucleotide state and tubulin conformation within the microtubules and, by extension, the relationship between tubulin conformation and the transition from assembled to disassembled microtubule structure," says a biophysicist on the study.
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https://www.sciencedaily.com/releases/2014/05/140522133406.htm

Talking about microtubular importance in capacity for thought, note that Alzheimer's disease is due to microtubular instability and disintegration, and memory and processing power along with them.

p.s. it may be possible to restore the failing microtubules and at least halt further damage in memory and thinking power. IMO, a truly noble goal.
 
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