7 ms·

Scientists watch a memory form in the brain of a living fish

129 points by doetoe 5y ago

gleenn 5y ago
Super cool, they added fluorescent proteins that activate when the neurons fire and did it in a Zebrafish which is transparent so they could literally watch the memories forming. Interesting also they wanted to keep the light as low as possible to not scorch the little guys.
- twoxproblematic 5y ago
  Are they not like rats where they "sacrifice" them regardless of the testing done?
  - echelon 5y ago
    > Are they not like rats where they "sacrifice" them regardless of the testing done? The protocols for lab animal euthanasia are incredibly humane. I don't mean to criticize you, but I think perspective can help anyone come to terms with this. When you think about what nature itself does to capture energy, that's at times incredibly savage and brutal. Gazelle on the Savannah being hunted and eaten alive by lions, rodents in the field being picked off by eagles, wasps laying eggs in live prey, fungi infecting the brains of animals and causing them to be eaten. Lab research may seem macabre, but it doesn't hold a candle to nature itself. And our lab research seeks an end of human disease and suffering. Even if we collectively decided that every human must behave in a way that doesn't kill any other life, one day our sun will burn out and all life on this planet will end.
  - DeWilde 5y ago
    Inflicting unnecessary pain during testing would be counter-productive to the testing goal.
overspeed 5y ago
I've always wondered if the fluorescent markers are visible to the fish and whether that might change their behaviour during experiments especially if it is a group interaction with other specimens who are not similarly modified.
rakkhi 5y ago
In fish... "Contrary to expectation, the synaptic strengths in the pallium remained about the same regardless of whether the fish learned anything. Instead, in the fish that learned, the synapses were pruned from some areas of the pallium — producing an effect “like cutting a bonsai tree,” Fraser said — and replanted in others." This is a very counter intuitive. So there are existing neural connections (formed somehow previously...) and new memories form by pruning these connections? Crazy
- stuu99 5y ago
  Not crazy, think of how quake levels are made with brushes, the brushes are "filled" solid and you carve out empty space to make paths and structures.
  - theWreckluse 5y ago
    Still crazy that evolution has chosen it.
  - theWreckluse 5y ago
    Crazy nonetheless that evolution has chosen it.
- dang 5y ago
  Ok, we've infished the title above. Thanks!
- randomsilence 5y ago
  That's consistent with the way, children react to languages and faces. When we are born, we are open to all languages. When we grow up, we only remain receptive to the language structures to which we had been exposed previously. Of course it's always possible to learn a new language, but it is easier with previous exposure. (citation needed)
- sva_ 5y ago
  I don't think it is counter intuitive (maybe if you hold a strong opinion, it is.) There's a growing body of evidence that brains, to some degree, learn by removing connections, and in some cases, add connections elsewhere. I think part of learning is, that we have some general idea about something, but it turns out to be inaccurate, so we need to specialize it (and get rid off the old connection.) I'm speculating though. I'm a bit confused by the "replanted in others" part though. I'd assume, overall, there is a net loss of synapses when learning (and hence learning becomes more difficult as we age - there just isn't enough entropy to prune away.) See also https://www.tcd.ie/news_events/articles/why-do-we-forget-new-theory-proposes-forgetting-is-actually-a-form-of-learning/ https://www.tcd.ie/news_events/articles/why-do-we-forget-new... And Discussion https://news.ycombinator.com/item?id=29940435 https://news.ycombinator.com/item?id=29940435 The article also has some older references - the idea isn't new.
randomsilence 5y ago
>While a developing mammalian brain grows by just getting bigger — “inflating like it’s a balloon” — the zebra fish brain almost turns itself inside out “like a popcorn kernel, so those deep centers are up near the surface where we can image them. Makes me wonder: How big is the hidden cost of destroying rain forests and other habitats? Every species that we lose is the loss of genetically encoded knowledge that could be very useful at some point. Could we protect the environment by making investment fonds eligible to the profits from genetic knowledge on the territory they own?
- sva_ 5y ago
  > How big is the hidden cost of destroying rain forests and other habitats? Incalculable, since we have no idea what we're losing?
bjornsing 5y ago
That doesn’t sound much like memory formation though, per se. Sounds more like adaptation / improved emotional regulation, which (less surprisingly) requires major rewiring.
plasticisbad 5y ago
I'm more concerned about the mechanism current memories being modified in actual developed cognition, regardless of age/location. Does it pass the "sniff test" if animals can't distinguish the difference?
Borrible 5y ago
https://en.wikipedia.org/wiki/Synaptic_pruning https://en.wikipedia.org/wiki/Synaptic_pruning
jwitchel 5y ago
Very nicely done. This is great research. Technical, creative, and substantive. Congrats to the whole team.
shikhardevgupta 5y ago
Looks super cool. I read about Neural Pathways in grad school, and seeing all that theory in action feels great.
retpirato 5y ago
Why didn't they try to create a good memory too, just to see if there appeared to be a difference in how it was created or stored?

129 points by doetoe 5y ago

Super cool, they added fluorescent proteins that activate when the neurons fire and did it in a Zebrafish which is transparent so they could literally watch the memories forming. Interesting also they wanted to keep the light as low as possible to not scorch the little guys.

twoxproblematic 5y ago
Are they not like rats where they "sacrifice" them regardless of the testing done?
- echelon 5y ago
  > Are they not like rats where they "sacrifice" them regardless of the testing done? The protocols for lab animal euthanasia are incredibly humane. I don't mean to criticize you, but I think perspective can help anyone come to terms with this. When you think about what nature itself does to capture energy, that's at times incredibly savage and brutal. Gazelle on the Savannah being hunted and eaten alive by lions, rodents in the field being picked off by eagles, wasps laying eggs in live prey, fungi infecting the brains of animals and causing them to be eaten. Lab research may seem macabre, but it doesn't hold a candle to nature itself. And our lab research seeks an end of human disease and suffering. Even if we collectively decided that every human must behave in a way that doesn't kill any other life, one day our sun will burn out and all life on this planet will end.
- DeWilde 5y ago
  Inflicting unnecessary pain during testing would be counter-productive to the testing goal.

overspeed 5y ago

I've always wondered if the fluorescent markers are visible to the fish and whether that might change their behaviour during experiments especially if it is a group interaction with other specimens who are not similarly modified.

rakkhi 5y ago

In fish... "Contrary to expectation, the synaptic strengths in the pallium remained about the same regardless of whether the fish learned anything. Instead, in the fish that learned, the synapses were pruned from some areas of the pallium — producing an effect “like cutting a bonsai tree,” Fraser said — and replanted in others." This is a very counter intuitive. So there are existing neural connections (formed somehow previously...) and new memories form by pruning these connections? Crazy

stuu99 5y ago
Not crazy, think of how quake levels are made with brushes, the brushes are "filled" solid and you carve out empty space to make paths and structures.
- theWreckluse 5y ago
  Still crazy that evolution has chosen it.
- theWreckluse 5y ago
  Crazy nonetheless that evolution has chosen it.
dang 5y ago
Ok, we've infished the title above. Thanks!
randomsilence 5y ago
That's consistent with the way, children react to languages and faces. When we are born, we are open to all languages. When we grow up, we only remain receptive to the language structures to which we had been exposed previously. Of course it's always possible to learn a new language, but it is easier with previous exposure. (citation needed)
sva_ 5y ago
I don't think it is counter intuitive (maybe if you hold a strong opinion, it is.) There's a growing body of evidence that brains, to some degree, learn by removing connections, and in some cases, add connections elsewhere. I think part of learning is, that we have some general idea about something, but it turns out to be inaccurate, so we need to specialize it (and get rid off the old connection.) I'm speculating though. I'm a bit confused by the "replanted in others" part though. I'd assume, overall, there is a net loss of synapses when learning (and hence learning becomes more difficult as we age - there just isn't enough entropy to prune away.) See also https://www.tcd.ie/news_events/articles/why-do-we-forget-new-theory-proposes-forgetting-is-actually-a-form-of-learning/ https://www.tcd.ie/news_events/articles/why-do-we-forget-new... And Discussion https://news.ycombinator.com/item?id=29940435 https://news.ycombinator.com/item?id=29940435 The article also has some older references - the idea isn't new.

randomsilence 5y ago

>While a developing mammalian brain grows by just getting bigger — “inflating like it’s a balloon” — the zebra fish brain almost turns itself inside out “like a popcorn kernel, so those deep centers are up near the surface where we can image them. Makes me wonder: How big is the hidden cost of destroying rain forests and other habitats? Every species that we lose is the loss of genetically encoded knowledge that could be very useful at some point. Could we protect the environment by making investment fonds eligible to the profits from genetic knowledge on the territory they own?

sva_ 5y ago
> How big is the hidden cost of destroying rain forests and other habitats? Incalculable, since we have no idea what we're losing?

bjornsing 5y ago

That doesn’t sound much like memory formation though, per se. Sounds more like adaptation / improved emotional regulation, which (less surprisingly) requires major rewiring.

plasticisbad 5y ago

I'm more concerned about the mechanism current memories being modified in actual developed cognition, regardless of age/location. Does it pass the "sniff test" if animals can't distinguish the difference?

Borrible 5y ago

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

jwitchel 5y ago

Very nicely done. This is great research. Technical, creative, and substantive. Congrats to the whole team.

shikhardevgupta 5y ago

Looks super cool. I read about Neural Pathways in grad school, and seeing all that theory in action feels great.

retpirato 5y ago

Why didn't they try to create a good memory too, just to see if there appeared to be a difference in how it was created or stored?