Author Topic: Question about authenticity of hell theough tesiminy, main part of question bold  (Read 3233 times)

xSilverPhinx

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What colour is the sky? There is no sky, Lucifer and all his demons had to literally go underground to escape the celestial Authority. 
What does the wind smell like? Like nothing. The excessive heat burns your smell receptors after a couple of breaths so you lose your sense of smell. 
How does the water taste? I like my water cold, so I wouldn't ever drink water in Hell. It's not like you can die again anyway. 
Where do the souls of the damned dwell? In overcrowded joint housing complexes with no air-conditioning. Argh, come to Porto Alegre, Brazil during the summer months and I'll show you hell.
Are there bridges over the rivers of lava?  No, most engineers go to Heaven, because many of them deny evolution and think just because man-made stuff like paintings and clocks are designed, therefore natural things like bananas and eyeballs must be too.

:rofl: Bananas...behold the atheists' nightmare!


At least Ray Comfort won't be there, right?
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I have a feeling that hell might just be a never ending seminar hosted by the likes of the Comforts and the Hovinds. Luke warm water, and oatmeal raisin disguised as chocolate chips are the refreshments.

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Where do the souls of the damned dwell?  Don't ask why, but I see them living under rocks.  They're very squished.

That reminded me of a joke my father told me as a child:

A man dies and is greeted at the gates of Hell by a rather friendly demon. The demon informs him that even though he has to suffer an eternity of torment it isn't all bad, he has at least some choice in how he spends it.

The demon leads him down a hallway and into a room full of people up to their armpits in shit, but all of them are drinking tea. He then asks the man if he would like to stay there. The man declines.

They go farther down the hallway to another room which is again filled with people up to their armpits in shit. The only difference is that everyone in this room is drinking Pepsi. The man seriously considers staying here but decides to go one more doorway down the hall.

In the third room the man is delighted to see that all of the shit stained inmates are drinking his favorite beverage. COFFEE! He thanks the demon for the tour, tells the demon that this is where he would like to stay and, almost happily, jumps into the nearest empty pile.

He gets his first cup of coffee and almost has it to his lips for a sip when the demon loudly calls out, "Alright everyone, break's over. Back on your heads!"
 

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 :rofl:  And yet also,  :sshocked:
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A bit of both, I would say, though finding the precise physical substrate of memory, of the engram, as it's called, is still frontier stuff. Huge leaps have been made in the last decade since the optogenetic method was developed, which can essentially label populations of neurons and turn memories on and off just as easily as flipping a light switch. It's a much 'cleaner' method than pharmacologically inactivating a brain region, but expensive, a little too expensive for most labs in developing countries. :(
:tellmemore: This here, it is SO much more fascinating than Hell on SO many levels, isn't it! And The Asmo, He got served an opening to pester a actual scientist about science. Resist, He could not.

I've read the article on optogenetics, and I think I get the principle of it on an educated-layman level. What I don't quite understand, is the delivery method(s). I mean, we are probably talking about a tiny target area, are we not? And there is the skull and all the gooey stuff in the way? They talk about viral vectors and some pretty cool genetic engineering, but how precise can such a thing be? I mean, I always thought that they were more of a carpet bomb approach on all cells of a particular type/possessing specific receptors. How "on-target" can such a delivery method be, when trying to pinpoint, say, a few thousand cells among millions "just like" them? What is The Asmo missing?  :headscratch: I suppose the Wiki article did mention that it was difficult, but their answers as to addressing the problem were... Slightly on the thin side.

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(then these lousy politicians who don't want to invest in science wonder why we're falling so behind, but anyways...)
*Sigh* I know... I've been fighting an uphill battle within the "movement" I'm sort-of affiliated with at the moment, trying to convince the populists that science is not some elitist conspiracy to drain their wallets and brainwash their children... Yes, I suppose I piled hyperbole thick on that one, but in my mind, this shouldn't be a question at all. If anything, we should overfund science. There are some potential sinkholes in that approach as well, but the spread of anti-scientific sentiments within the "enlightened" society disturbs me.

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It's believed that a memory trace comes from both the physical organisation of neurons into networks and the strength of connections between neurons. It takes a few hours to consolidate a memory at celular levels (synaptic consolidation - cells), and days, months and even years at the systemic level in the case of humans (systemic consolidation - circuits), though not all types of memories undergo this latter type of consolidation.   ;D
Point of order; is the strength of connection related to the number of dendrites/branches between two neurons? Kind of like the electron sharing in a covalent bond?

That said, isn't it cool how one may just think of a memory as an imperfect snapshot of the past, when from what I read here, it is in fact more of an imperfect re-telling of the past, "finalised," for the lack of a more applicable word, some time after the actual event took place? Makes one wonder to what degree the events we remember happened in the way we remember them.

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There are currently three major hypotheses that attempt to explain what happens as memories become systemically consolidated, the Standard Model, the Multiple Trace Theory and the updated version, Trace Transformation Theory. In all, the hippocampus, which is a structure located in the medial temporal lobe more or less between the ears in humans, is responsible for forming memories. You remove that structure and you will have access to some remote memories, but will be incapable of acquiring new ones. In Alzheimer's for instance, the hippocampus is one of the first structures to suffer damage, which is one of the reasons sufferers often regress back to ancient memories, such as when they were a child, etc.

There is still no consensus on which should be the prevailing theory, so it's still a little fuzzy. Also frontier stuff. :grin:
Hm... Does the retention of some remote memory without a hippocampus suggest that memory has some "mobility" in regard to where exactly it is "stored," as you point out below, or is it more a case of some memories happening to be "deeper?" (I suppose I can see how that could be the case with early childhood memories, for example. The brain does grow in them early years, after all, though the exact method of its expansion is not something I'm familiar with - hence the question. Do we know that they "migrate," or are the childhood memories just deep because, to put it crudely, more cells were piled on them during growth?)

I have not heard of the Trace Transformation Theory. Will check it out. I mean, I'm far, FAR from qualified to pass any sort of judgement on its validity and such, but it is fun to at least be able to recognise the avenues along which the modern scientists think.

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I won't go into minute details, but the main idea in all of them is that memories start in the hippocampus and "migrate" to cortical structures with time. That's basically what systems consolidation is about. The hippocampus goes offline and is not important in the recall of remote memories (according to the Standard model) but it still participates (according to the two others).
One thing I've wondered about for a long time, though. I understand that recalling a memory involves some firing of specific neurons, perhaps in specific ways. How does one trigger that, though? I mean, if I make a conscious effort to recall a mathematical formula, for example, I can usually do that. In computer engineering, that would be sort-of analogous to an indexed database search. I look up under "math," then "equations," etc, until I narrow my search results to one (Or however many are applicable) Humans don't index like that, or at least don't have conscious access to such an index, so how do I "know" which neurons to trigger to dredge up some "long-forgotten" mathematics?


I'm liking the heck out of this thread, by the way. Thanks for a great quality reply!

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Asmodean

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Just for fun:

What colour is the sky?  Red and orange with bits of yellow.
What does the wind smell like?  Sulfur.
How does the water taste?  Probably like the water in Flint, MI.
Where do the souls of the damned dwell?  Don't ask why, but I see them living under rocks.  They're very squished.
Are there bridges over the rivers of lava?  No, you have to swim across.

And I don't even believe in Hell.
See, this is a good example of suggestion in "action." Sandra's Hell is at least partly outdoors, though on a cloudy day, on a planet orbiting a red dwarf. It has an atmosphere, specifically that of Venus. They have terrible lead problems with their water, which apparently also exists in hell, and there are indeed souls of the damned there, swimming across the lakes of lava to be squished under rocks. Now, Sandra played a suggestion back to me, and now I imagine Hell as being rather on the rocky side.

Basically, we are co-authoring a fantasy here.

What colour is the sky? There is no sky, Lucifer and all his demons had to literally go underground to escape the celestial Authority. 
What does the wind smell like? Like nothing. The excessive heat burns your smell receptors after a couple of breaths so you lose your sense of smell. 
How does the water taste? I like my water cold, so I wouldn't ever drink water in Hell. It's not like you can die again anyway. 
Where do the souls of the damned dwell? In overcrowded joint housing complexes with no air-conditioning. Argh, come to Porto Alegre, Brazil during the summer months and I'll show you hell.
Are there bridges over the rivers of lava?  No, most engineers go to Heaven, because many of them deny evolution and think just because man-made stuff like paintings and clocks are designed, therefore natural things like bananas and eyeballs must be too.
And this is a person recognising what I'm doing and being subversive with it.  8)

The Asmo hath claimed this thread for quality education.  :pedant:
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I like the direction this thread is taking. Asmo, I will address your questions after I've had copious amounts of caffeine and am fully awake.  :teadrink:
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Now, Sandra played a suggestion back to me, and now I imagine Hell as being rather on the rocky side.

Basically, we are co-authoring a fantasy here.


And so all myths are born, I imagine.  Also, since every Xtian I know who believes in Hell thinks it's part of the supernatural realm, wouldn't that mean our laws of physics don't apply to it?  (Which really is extremely convenient for something there is no evidence for.)
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I've read the article on optogenetics, and I think I get the principle of it on an educated-layman level. What I don't quite understand, is the delivery method(s). I mean, we are probably talking about a tiny target area, are we not? And there is the skull and all the gooey stuff in the way? They talk about viral vectors and some pretty cool genetic engineering, but how precise can such a thing be? I mean, I always thought that they were more of a carpet bomb approach on all cells of a particular type/possessing specific receptors. How "on-target" can such a delivery method be, when trying to pinpoint, say, a few thousand cells among millions "just like" them? What is The Asmo missing?  :headscratch: I suppose the Wiki article did mention that it was difficult, but their answers as to addressing the problem were... Slightly on the thin side.

As far as I know, it isn't 100% precise, not all cells end up transfected with the gene for producing channels that respond to light (opsins). Most high-quality scientific papers will mention what percentage of the cells that were sucessfully transfected.

It's one major problem with this method. Sometimes even different cells will expressed different amounts of opsins on their membrane, which could influence some results. 

In order to target specific neurons and not others, it will depend on the protocol. For instance, in the field of learning and memory, if you want to label a specific population that is active during acquisition to later manipulate that population with light in order to momentarily erase or enhance the memory, you focus on Immediate Early Genes, which are quickly transcribed after learning to strengthen connections between neurons and so on. Promotors and/or genes which act on those specifically are added to the genetic construct.

Besides wanting only certain cells to express opsins there is the issue of timing to consider. In order to make sure that only cells active during a defined time (such as the acquisition of a memory) get labelled, researchers commonly add doxycycline (Dox) to their food. Dox blocks transcription and so keeps opsins from getting made at the wrong time. 

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*Sigh* I know... I've been fighting an uphill battle within the "movement" I'm sort-of affiliated with at the moment, trying to convince the populists that science is not some elitist conspiracy to drain their wallets and brainwash their children... Yes, I suppose I piled hyperbole thick on that one, but in my mind, this shouldn't be a question at all. If anything, we should overfund science. There are some potential sinkholes in that approach as well, but the spread of anti-scientific sentiments within the "enlightened" society disturbs me.

Tell me about it. ::)

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Point of order; is the strength of connection related to the number of dendrites/branches between two neurons? Kind of like the electron sharing in a covalent bond?

Yes, it's also related to how strong each individual synapse is. It's worth remembering that synapses don't actually touch each other but are instead separated by a cleft, therefore an electrical signal must be translated into a chemical one to pass the gap and become an electrical signal in another neuron. On the receiving neuron's (called the post-synaptic neuron) dendrites there are small protruding structures called dendritic spines, which are exactly where the synapse is. Stronger synapses will have more receptors packed on the membrane of these protrusions.

Technically, increased synaptic strength is produced by LTP. When that happens biochemical cascades result in there being more receptors there to receive the incoming chemical signal and propagate an electrical one. In the case of excitatory neurons, if and when they pass a threshold an action potential will result, and the signal will be propagated to the next neuron.

Quote
That said, isn't it cool how one may just think of a memory as an imperfect snapshot of the past, when from what I read here, it is in fact more of an imperfect re-telling of the past, "finalised," for the lack of a more applicable word, some time after the actual event took place? Makes one wonder to what degree the events we remember happened in the way we remember them.

 ;D Oh yeah. . People like to use computer memories as analogous to our own but it is a terrible analogy because ours are definitely not perfect portraits of the past. Think of it this way. You have an image stored on your computer. Every time to click on that image it changes a little, especially if it's a recent file. You close the image. You click on it again, it changes a little more. Eventually, with time, you can have a generic, "gist-like" image which has lost some detail and acquired others. There are factors which influence just how much of this happens, just as emotional content and age of the memory -- the so-called boundary conditions. A lot of work goes into trying to figure out these factors.

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Hm... Does the retention of some remote memory without a hippocampus suggest that memory has some "mobility" in regard to where exactly it is "stored," as you point out below, or is it more a case of some memories happening to be "deeper?" (I suppose I can see how that could be the case with early childhood memories, for example. The brain does grow in them early years, after all, though the exact method of its expansion is not something I'm familiar with - hence the question. Do we know that they "migrate," or are the childhood memories just deep because, to put it crudely, more cells were piled on them during growth?)

It has a lot more to do with processing. The hippocampus, being part of the older region of the brain, evolutionarily, has fewer layers than the neocortex. However, the cells are arranged more orderly, so as the theory goes it has more power to process detailed memories. When memories become more dependant on cortical structures, in which cells are more sparse, they tend to lose detail, and memories become what we call 'generalised'. But what is believed is that memories do not become totally independent of the hippocampus (contrary to what the Standard Model implies).

In reality no one knows where memories are stored. Depends on the type of memory. Depends on how it was acquired, the emotional content, other mediating structures... When I said "migrate" I put the word between :airquotes: precisely because it may not technically migrate at all.

There is a recent-ish paper by an MIT lab (Tonegawa's) in which they showed, using optogentics that when a new memory is formed in the hippocampus, it is also formed in the cortex. With time connections between these two areas are strengthened and the memory becomes increasingly reliant on cortical structures, but the engram is activated in the hippocampus as well. 

Which brings me to...   


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I have not heard of the Trace Transformation Theory. Will check it out. I mean, I'm far, FAR from qualified to pass any sort of judgement on its validity and such, but it is fun to at least be able to recognise the avenues along which the modern scientists think.

Yes, check it out. Of all the hypotheses it's the most valid, I think. ;D

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One thing I've wondered about for a long time, though. I understand that recalling a memory involves some firing of specific neurons, perhaps in specific ways. How does one trigger that, though? I mean, if I make a conscious effort to recall a mathematical formula, for example, I can usually do that. In computer engineering, that would be sort-of analogous to an indexed database search. I look up under "math," then "equations," etc, until I narrow my search results to one (Or however many are applicable) Humans don't index like that, or at least don't have conscious access to such an index, so how do I "know" which neurons to trigger to dredge up some "long-forgotten" mathematics?

According to the Trace Transformation Theory, the hippocampus acts sort of like an indexer, even for remote memories, which is why memories never really cease to be hippcampus-independent.  8)
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That said, isn't it cool how one may just think of a memory as an imperfect snapshot of the past, when from what I read here, it is in fact more of an imperfect re-telling of the past, "finalised," for the lack of a more applicable word, some time after the actual event took place? Makes one wonder to what degree the events we remember happened in the way we remember them.

 ;D Oh yeah. . People like to use computer memories as analogous to our own but it is a terrible analogy because ours are definitely not perfect portraits of the past. Think of it this way. You have an image stored on your computer. Every time to click on that image it changes a little, especially if it's a recent file. You close the image. You click on it again, it changes a little more. Eventually, with time, you can have a generic, "gist-like" image which has lost some detail and acquired others. There are factors which influence just how much of this happens, just as emotional content and age of the memory -- the so-called boundary conditions. A lot of work goes into trying to figure out these factors.


This is one of the reasons I don't completely trust eye witness reports of events, especially in criminal cases where capital punishment is on the cards (fortunately not in my country).  Backed up with corroborating evidence it is fine even valuable, but on its own not so much.  Human memory is too easily influenced by what we want to remember or what has been suggested to us.
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Asmodean

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As far as I know, it isn't 100% precise, not all cells end up transfected with the gene for producing channels that respond to light (opsins). Most high-quality scientific papers will mention what percentage of the cells that were sucessfully transfected.

It's one major problem with this method. Sometimes even different cells will expressed different amounts of opsins on their membrane, which could influence some results.
Yes, that's more or less what I thought. A point of curiosity, though; if an unwanted population of cells is affected in addition to the population you aim at, how "contaminated" can a sample be, in order for a memory experiment to still be viable? Also, the engineer in me sort-of sees potential for "cleaning up" the contamination in the course of experiment. Rather, if you know which cell populations are affected, can you filter the signal from the "wrong" cells out of your sample?

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In order to target specific neurons and not others, it will depend on the protocol. For instance, in the field of learning and memory, if you want to label a specific population that is active during acquisition to later manipulate that population with light in order to momentarily erase or enhance the memory, you focus on Immediate Early Genes, which are quickly transcribed after learning to strengthen connections between neurons and so on. Promotors and/or genes which act on those specifically are added to the genetic construct.

Besides wanting only certain cells to express opsins there is the issue of timing to consider. In order to make sure that only cells active during a defined time (such as the acquisition of a memory) get labelled, researchers commonly add doxycycline (Dox) to their food. Dox blocks transcription and so keeps opsins from getting made at the wrong time.
Ah! Am I understanding correctly, that this means that there actual physiological differences in cells which were recently "written to," as compared to those cells around them, which were not? It makes sense, but I must admit I've never thought about it that way. It's absolutely fascinating that we, lowly humans, over such a historically miniscule period of time, actually managed to not only discover those differences, but also use them for experimental purposes. I mean, there is a whole mess of sciences at play here, all interconnected and co-dependent.

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Yes, it's also related to how strong each individual synapse is. It's worth remembering that synapses don't actually touch each other but are instead separated by a cleft, therefore an electrical signal must be translated into a chemical one to pass the gap and become an electrical signal in another neuron. On the receiving neuron's (called the post-synaptic neuron) dendrites there are small protruding structures called dendritic spines, which are exactly where the synapse is. Stronger synapses will have more receptors packed on the membrane of these protrusions.

Technically, increased synaptic strength is produced by LTP. When that happens biochemical cascades result in there being more receptors there to receive the incoming chemical signal and propagate an electrical one. In the case of excitatory neurons, if and when they pass a threshold an action potential will result, and the signal will be propagated to the next neuron.
This is another thing I never thought about. You see on illustrations of stuff like dopamine or serotonin uptake, that they always draw a space between the cells, in which the chemicals "fly" between receptors. I always assumed that it was purely for illustrative convenience, and that the neural "wires" were continuous, if made of a myriad individual strands.

Makes an person wonder, is this at least partly the reason for our "sensory lag?" As in, from light hits the retina and until the brain has an image to process, for example? I mean, light, it moves at the speed of light. Chemical reactions - not so much, and transmission of chemicals may be slower still.

Thanks for the link; for the above-described reason, I originally thought about strength of a synaptic link from more from a structural/signal integrity standpoint, rather than signal throughput capability. I think I finally get the use of "strength" in this case. They have these four illustrations, what clarify what is meant very nicely. Also, they raise some suspicions in an enterprising Asmo about stuff like serotonin storms and drug resistances (as in, those popping pain killers tend to need higher and higher dosages) and where and how such conditions operate.

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;D Oh yeah. . People like to use computer memories as analogous to our own but it is a terrible analogy because ours are definitely not perfect portraits of the past. Think of it this way. You have an image stored on your computer. Every time to click on that image it changes a little, especially if it's a recent file. You close the image. You click on it again, it changes a little more. Eventually, with time, you can have a generic, "gist-like" image which has lost some detail and acquired others. There are factors which influence just how much of this happens, just as emotional content and age of the memory -- the so-called boundary conditions. A lot of work goes into trying to figure out these factors.
Oh, I can see how it takes a lot of people a lot of hours (not to mention all those thousands of heroic ratties, who show up and do their part every day, in the name of their God, in order to further human understanding of the natural world) to figure this stuff out. I mean, I'm pretty sure that most of the questions I ask are barely above high school level, because that's where my understanding of this topic is, but it's damned interesting. You have a really cool job!

I like your picture analogy. The one I thought up, was more along the lines of oral tradition of storytelling - with each passing generation, the story changes a little, without quite losing what it used to be. It's a bit like... Evolution, actually. Every child is of the same species as its parents, and yet given enough generations, the species are similar, but completely different. It even works, in a manner, in distinguishing stuff like generalised memories (a human is a hominid is a mammal is a vertebrate). I likes my analogy and hereby claims copyright! :D (Yes, yes, I know, but don't tell me that somebody already made it a hundred years ago. Is MY epiphany now)

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It has a lot more to do with processing. The hippocampus, being part of the older region of the brain, evolutionarily, has fewer layers than the neocortex. However, the cells are arranged more orderly, so as the theory goes it has more power to process detailed memories. When memories become more dependant on cortical structures, in which cells are more sparse, they tend to lose detail, and memories become what we call 'generalised'. But what is believed is that memories do not become totally independent of the hippocampus (contrary to what the Standard Model implies).

In reality no one knows where memories are stored. Depends on the type of memory. Depends on how it was acquired, the emotional content, other mediating structures... When I said "migrate" I put the word between :airquotes: precisely because it may not technically migrate at all.

There is a recent-ish paper by an MIT lab (Tonegawa's) in which they showed, using optogentics that when a new memory is formed in the hippocampus, it is also formed in the cortex. With time connections between these two areas are strengthened and the memory becomes increasingly reliant on cortical structures, but the engram is activated in the hippocampus as well. 
So... It's kind of like different parts of the brain are responsible for discrete levels of intricacy of a given memory? Yes, this right here, is where a lot of very cool answers lie. It would be really interesting to figure out if a memory, once "written," is static to that general cluster of neurons, or if it can indeed be "transferred" from one to the other. What quality, or "resolution," if you will, would such a memory hold, I wonder... Actually, given what I've read about the experiments being done in this field in this very conversation, I wonder if transplanting a memory, however imperfectly, is not a doable experiment? Has it been done, or at the very least proposed, perchance?

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According to the Trace Transformation Theory, the hippocampus acts sort of like an indexer, even for remote memories, which is why memories never really cease to be hippcampus-independent.  8)
Oh, this, I'm definitely reading up on. I expect I'll have to bounce some questions off you and clear up some misunderstandings, what with my bias towards seeing the world through a pair of engineer-glasses.  8)
« Last Edit: September 28, 2018, 03:21:57 PM by Asmodean »
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That said, isn't it cool how one may just think of a memory as an imperfect snapshot of the past, when from what I read here, it is in fact more of an imperfect re-telling of the past, "finalised," for the lack of a more applicable word, some time after the actual event took place? Makes one wonder to what degree the events we remember happened in the way we remember them.

 ;D Oh yeah. . People like to use computer memories as analogous to our own but it is a terrible analogy because ours are definitely not perfect portraits of the past. Think of it this way. You have an image stored on your computer. Every time to click on that image it changes a little, especially if it's a recent file. You close the image. You click on it again, it changes a little more. Eventually, with time, you can have a generic, "gist-like" image which has lost some detail and acquired others. There are factors which influence just how much of this happens, just as emotional content and age of the memory -- the so-called boundary conditions. A lot of work goes into trying to figure out these factors.


This is one of the reasons I don't completely trust eye witness reports of events, especially in criminal cases where capital punishment is on the cards (fortunately not in my country).  Backed up with corroborating evidence it is fine even valuable, but on its own not so much.  Human memory is too easily influenced by what we want to remember or what has been suggested to us.

Definitely. Here's an interesting TED talk given by false memory researcher Elizabeth Loftus.


She uses an interesting analogy for memory: it's like a Wikipedia page that you can edit, but not only that, other people can edit it too.

I'll have to steal that analogy. ;D
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Yes, that's more or less what I thought. A point of curiosity, though; if an unwanted population of cells is affected in addition to the population you aim at, how "contaminated" can a sample be, in order for a memory experiment to still be viable? Also, the engineer in me sort-of sees potential for "cleaning up" the contamination in the course of experiment. Rather, if you know which cell populations are affected, can you filter the signal from the "wrong" cells out of your sample?

You got me there, I have no idea.  :(  I'm guessing that it's not the case that there's absolutely no contamination.

However, when compared to the pharmacological approach, in which you basically inject a drug into the desired area of the brain, it will act on many, many cells in that region, even ones that wouldn't have been recruited anyway. Even so, you can still see behavioural effects that indicate more or less what is likely happening. Problem is there are compensatory netowrks that also come into play, but I won't ramble on about that...

So, in comparison, optogenetics and even chemogenetics (DREADDs - you might like that name  ;D) are far "cleaner" than the pharmacological approach.

Pharmacology is what I have to work with, but I dream of an opportunity to possibly spend some time in a lab with money to spare and has the whole optogenetic toolkit at their disposal. :tellmemore:

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Ah! Am I understanding correctly, that this means that there actual physiological differences in cells which were recently "written to," as compared to those cells around them, which were not? It makes sense, but I must admit I've never thought about it that way. It's absolutely fascinating that we, lowly humans, over such a historically miniscule period of time, actually managed to not only discover those differences, but also use them for experimental purposes. I mean, there is a whole mess of sciences at play here, all interconnected and co-dependent.

Yes, there are loads of physiological differences between neurons that are activated, and at different time points too. For instance, the Early Immediate Genes I mentioned earlier result in proteins that are expressed by only the neurons that were recruited. We can see those too, using immunohistology techniques. One such gene is FOS, which encodes for the c-fos protein.


This is a section of a rat hippocampus (proportionally larger than ours). 8) The red/orangy cells are ones which were last recruited during a behavioural task, which express the early immediate gene protein, c-fos. The green dots are neurons and blue dots are the nuclei of neurons and glial cells.

I could stare at that image all day.  :tellmemore:

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This is another thing I never thought about. You see on illustrations of stuff like dopamine or serotonin uptake, that they always draw a space between the cells, in which the chemicals "fly" between receptors. I always assumed that it was purely for illustrative convenience, and that the neural "wires" were continuous, if made of a myriad individual strands.

 ;D Funnily enough, that was the debate/argument that Golgi and Ramón y Cajal ("father of neuroscience") had at the turn of the 20th century. Golgi believed that everything was continuous while Cajal said that cells were discrete units, not continuously joined. Cajal was right, but both were awarded the Nobel prize. 

https://en.wikipedia.org/wiki/Reticular_theory

 :o Ah, I had to list the distinction between two types of synapse in the entry exam for my master's...let's see if I can still remember:

There are two types of synapses, electrical, which are in physical contact with eachother and there are no neurotransmitters, and chemical, in which there is a cleft between them and neurotransmitters are necessary to get the signal across. In invertebrates, synapses are mostly electrical whereas in vertebrates they're mostly chemical. Electrical synapses are bidirectional whereas chemical synapses go only in one direction, from the presynaptic neuron to the postsynaptic neuron, though there are the so-called 'atypical neurotransmitters', such as endocannabinoids that go in the inverse direction (yes, our systems produce cannabinoids  ;D ).

What else...

Electrical synapses are faster than chemical ones. But if they're faster, then why have chemical synapses in the first place, and why do 'more evolved' animals such as vertebrates have more chemical synapses? One answer is that chemical synapses are regulated. They're more complex, but there are more 'steps' along the way that can be inhibited, facilitated or modulated, resulting in a larger behavioural repertoire.   

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Makes an person wonder, is this at least partly the reason for our "sensory lag?" As in, from light hits the retina and until the brain has an image to process, for example? I mean, light, it moves at the speed of light. Chemical reactions - not so much, and transmission of chemicals may be slower still.

See above.

The difference in speed between the two types of synapses isn't so great, though. Since most neurotransmitters are small molecules that can diffuse rapidly and the cleft is tiny, there is only a small delay.


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Oh, I can see how it takes a lot of people a lot of hours (not to mention all those thousands of heroic ratties, who show up and do their part every day, in the name of their God, in order to further human understanding of the natural world) to figure this stuff out. I mean, I'm pretty sure that most of the questions I ask are barely above high school level, because that's where my understanding of this topic is, but it's damned interesting. You have a really cool job!

:grin: Yes, it's a cool job, but can be damned frustrating, though! That's science for ya.

As for the ratties, yes, they are heroic. One of my labmates even added them in the acknowledgement part of his thesis. I thought that was awesome.

While animal experimentation is a controversial topic (my family, for instance, does not approve), all experiments have to be approved by an ethics committee made up of people from many backgrounds before they can be done. You have to be rigorous in your justification for using animals before you can use them. That's why scientists have to be 'salespeople' as well, you have to 'sell' your idea to others all the time.     

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I like your picture analogy. The one I thought up, was more along the lines of oral tradition of storytelling - with each passing generation, the story changes a little, without quite losing what it used to be. It's a bit like... Evolution, actually. Every child is of the same species as its parents, and yet given enough generations, the species are similar, but completely different. It even works, in a manner, in distinguishing stuff like generalised memories (a human is a hominid is a mammal is a vertebrate). I likes my analogy and hereby claims copyright! :D (Yes, yes, I know, but don't tell me that somebody already made it a hundred years ago. Is MY epiphany now)

:lol:


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So... It's kind of like different parts of the brain are responsible for discrete levels of intricacy of a given memory? Yes, this right here, is where a lot of very cool answers lie. It would be really interesting to figure out if a memory, once "written," is static to that general cluster of neurons, or if it can indeed be "transferred" from one to the other. What quality, or "resolution," if you will, would such a memory hold, I wonder... Actually, given what I've read about the experiments being done in this field in this very conversation, I wonder if transplanting a memory, however imperfectly, is not a doable experiment? Has it been done, or at the very least proposed, perchance?

Memories tend to become more generalised when they become more dependent on cortical structures. They lose detail, and become more 'semantic'. This means that they do lose some precision, and some researchers have proposed it is a form of forgetting, but I think not. Generalisation is not the same as forgetting.

Implanting memories?  :unsure: I don't think it's theoretically possible to 100% transfer a memory because everyone's brain in different in their connections, memories are coloured by perception as well, and attention...I don't know. I'll have to look into that. It would be cool if it were possible, though! :grin:


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Oh, this, I'm definitely reading up on. I expect I'll have to bounce some questions off you and clear up some misunderstandings, what with my bias towards seeing the world through a pair of engineer-glasses.  8)

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That said, isn't it cool how one may just think of a memory as an imperfect snapshot of the past, when from what I read here, it is in fact more of an imperfect re-telling of the past, "finalised," for the lack of a more applicable word, some time after the actual event took place? Makes one wonder to what degree the events we remember happened in the way we remember them.

 ;D Oh yeah. . People like to use computer memories as analogous to our own but it is a terrible analogy because ours are definitely not perfect portraits of the past. Think of it this way. You have an image stored on your computer. Every time to click on that image it changes a little, especially if it's a recent file. You close the image. You click on it again, it changes a little more. Eventually, with time, you can have a generic, "gist-like" image which has lost some detail and acquired others. There are factors which influence just how much of this happens, just as emotional content and age of the memory -- the so-called boundary conditions. A lot of work goes into trying to figure out these factors.


This is one of the reasons I don't completely trust eye witness reports of events, especially in criminal cases where capital punishment is on the cards (fortunately not in my country).  Backed up with corroborating evidence it is fine even valuable, but on its own not so much.  Human memory is too easily influenced by what we want to remember or what has been suggested to us.

Definitely. Here's an interesting TED talk given by false memory researcher Elizabeth Loftus.
<Youtube video edited out for brevity>
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She uses an interesting analogy for memory: it's like a Wikipedia page that you can edit, but not only that, other people can edit it too.

I'll have to steal that analogy. ;D

Wow!  Thank you for posting that TED talk, it was extremely interesting.  Makes me wonder a bit about the basis of our entire criminal justice system.  Just how can so many cases rely so much on eye witness accounts when we now know they are completely unreliable, no matter how sincere the witness may be.
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Practically, until recently in historical terms, "he said she said" was all we had. There was no DNA, no way to analyse bodily fluids, no way to tie the axe to the axe killer besides the testimony of the axe-maker... Etc.

Also, until recently, the justice system pretty much all over the world was "purely" punitive in nature. I think the problem is that the courts have failed to evolve with the times in some areas. Relying on the unreliable human jabbering is one such.

Now, back to muh neuroscience :D
 
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