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Researchers Tweak Mouse Neurons To Activate Specific Memories

Soulskill posted more than 2 years ago | from the shine-a-laser-in-your-brain-to-find-your-keys dept.

Biotech 29

An anonymous reader writes "According to new study published in Nature (abstract), MIT researchers have figured out how to trigger specific memories in rats by hitting certain neurons with a pulse of light. From the article: 'The researchers first identified a specific set of brain cells in the hippocampus that were active only when a mouse was learning about a new environment. They determined which genes were activated in those cells, and coupled them with the gene for channelrhodopsin-2 (ChR2), a light-activated protein used in optogenetics. ... The light-activated protein would only be expressed in the neurons involved in experiential learning — an ingenious way to allow for labeling of the physical network of neurons associated with a specific memory engram for a specific experience. Finally, the mice entered an environment and, after a few minutes of exploration, received a mild foot shock, learning to fear the particular environment in which the shock occurred. The brain cells activated during this fear conditioning became tagged with ChR2. Later, when exposed to triggering pulses of light in a completely different environment, the neurons involved in the fear memory switched on — and the mice quickly entered a defensive, immobile crouch.'"

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Total recall (3, Funny)

Reverand Dave (1959652) | more than 2 years ago | (#39454351)

Next up, a vacation without without going anywhere!

I want to go to maaahz (0)

Anonymous Coward | more than 2 years ago | (#39454533)

I said I want to go to maaahz!!!

Re:Total recall (2)

g0bshiTe (596213) | more than 2 years ago | (#39454665)

I'm confused, is it mice or rats? Or do these scientists not know the difference.

Re:Total recall (3, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#39454787)

It's mice. The unawareness is restricted to the editor and/or submitter. You may find this pattern familiar.

Re:Total recall (1)

b4dc0d3r (1268512) | more than 2 years ago | (#39455823)

It has become clear to me that editors and submitters both have cells tagged with ChR2 pretty much at random, and typing seems to engage triggering pulses of light.

We are all part of the experiment, I think it's to see who is the last one to give up waiting for quality to improve.

I'm going to read one more summary and if it sucks I'm done. Well that was obviously a dud, I'll give it a pass and the next one will determine it. Wait, that was idle, I'll see what the next one has...

Re:Total recall (1)

Samantha Wright (1324923) | more than 2 years ago | (#39456925)

I think it's more likely that it's NpHR: a related channelrhodopsin protein that suppresses neuron firing when activated.

Re:Total recall (1)

GLMDesigns (2044134) | more than 2 years ago | (#39458173)

We might not be in the world of Total Recall but we're getting there. Researchers have been able to "read" thoughts (see: [] ) and now this. Who says you need magic to store memories in a penseive? We're going to be there faster that you think.

Fascinating (1)

courteaudotbiz (1191083) | more than 2 years ago | (#39454389)

Your best souvenirs are just a flash of light away. However, you have to accept to be lobotomized and have a laser trigger some cells in your brain, but this is just a detail!

I rather close my eyes and think about stuff that I can remember. I can even think about stuff that has not happened yet :-)

Didn't RTFA, as usual.

Re:Fascinating (2)

Ihmhi (1206036) | more than 2 years ago | (#39454777)

Think of the defense applications!

An angry group of foreign citizens have surrounded the American Embassy in Egypt. All hope is lost. Suddenly, a flash of light from the roof - and everyone falls over vomiting and crying as they think about that one time they saw their parents fucking.

Hollywood beat them to it (0)

Anonymous Coward | more than 2 years ago | (#39454427)

Sorta makes me see Eternal Sunshine of the Spotless Mind in a whole new light.

Re:Hollywood beat them to it (1, Interesting)

wierd_w (1375923) | more than 2 years ago | (#39454769)

While I have no doubt that some aspiring psychologist and neurosurgeons would work to create a read/write memory machine for the purposes of treating PTSD, (memory can't trigger if the memory is destroyed. Patient lives a happier and more normal life), it would only be a short jump for the tech on say, DARPA's hands, and you have more of a Universal Soldier type situation, and from there, real, genuine thought police.

Personally though, I look at this in the light of yesterday's news about microtubule structures that preserve memories encoded in axons electrochemically, coupled with a photosensitive protien.

Looks to me like the two sets of researchers are exploring differing parts of the same mechanism, and have discovered that their light sensitive protien triggers shaped memory playback in a neuron similarly to the electrical potential it would experience if it was stimulated by another neuron.

If this were coupled with say, genes for OLEDs, then a neural transiever wouldn't need to rely on invasive contact with the brain to interface meaningfully. Exchanged bursts of photons would be sufficient.

With some improvements in organic semiconductor (plastic) tech, it is entirely feasible to imagine somebody having their brains "painted" in the interface layer like spraypaint. (A water permeable photocuring biopolymer. Perhaps something like liquid silk, with a twist. Without being set by light, it biodegrades, limiting the retardation of the method used by the cerebreal spinal fluid for keeping the brain healthy. ) after that, a controled laser aperature draws all the circuits on top of the brain, passively coupling the synthetic with the biological with a tough, durable, and flexible substrate. A blood plasma tap off the corotid artery for a glucose power cell, and an antenna array printed onto the inside of the cranial cap, and you have yourself a programmable organism.

Pure science fiction at this point, but I could clearly see it happening (in at least a lab). The interface would not introduce any contaminating ions into the mix, and wouldn't be directly connected electronically to the brain. All communication would be photonically transmitted, both directions.

Ethics aside, it would make the manchurian candidate frightfully possible to create.

Re:Hollywood beat them to it (1)

mikael (484) | more than 2 years ago | (#39455473)

Psychologists and patients can get by with VR simulations using a VR glasses and a powerful gaming PC. They just ctrate a game map that resembles the experience that gave the patient PTSD and gradually increase the realism. They can also create regular street scenes with car engines backfiring, motorists yelling, construction workers running machinery and dropping crates. Gradually they desensitize the patients to these stimuli.

Re:Hollywood beat them to it (1)

cyberfringe (641163) | more than 2 years ago | (#39455551)

I like the way you think. Color outside the box? What box! A technology such as this could have many positive applications as well. Need to learn how to fly a helicopter in an emergency? Flash. Done. It is a good question whether skills can be evoked in the same manner these experimenters have activated memories.

Hm... (1)

Anonymous Coward | more than 2 years ago | (#39454565)

We're not torturing him, we're just shining this light on him.
It's not our fault he's reliving having his arm torn off over and over.

Re:Hm... (1)

Githaron (2462596) | more than 2 years ago | (#39455403)

We're not torturing him, we're just shining this light on him. It's not our fault he's reliving having his arm torn off over and over.

We're not cutting off his fingers, we're just pushing a blade into them. It's not our fault that his fingers don't hold together.

Bigboote, use more honey!! (0)

jimmytheant (596182) | more than 2 years ago | (#39454713)

Finally reproducing Lizardo's work I see...

Of Mice and Memories.. (1)

s.petry (762400) | more than 2 years ago | (#39454813)

Lenny was not at fault, it was some homeless guy petting you.

I'm sure there are countless politicians with a hard on just thinking about how to use this...

Combine TFA with other discoveries (1)

jd (1658) | more than 2 years ago | (#39454883)

The protein structures behind memory are beginning to be understood:

(Discovery of mBDNF) []
(CaMKII association) []
(RNA handling of the proteins) []

We're now very close to understanding how memories form and are activated.

Re:Combine TFA with other discoveries (1)

raftpeople (844215) | more than 2 years ago | (#39456675)

Did you see this one that hypothesizes that modifications to microtubules inside neurons are the mechanism for memory (and possibly computation), with each neuron possibly storing many "bytes" of information?

Re:Combine TFA with other discoveries (1)

jd (1658) | more than 2 years ago | (#39456771)

Thanks for that! I'd remembered seeing a reference to it, but hadn't found the original article and couldn't find where I'd seen the original reference. However memory works, I need an upgrade. A 16K expansion pack should suffice.

Now, if the neuron can indeed be coded this way, it would explain why just a few rat neurons can handle a flight simulator just fine. It would also explain why current models of biological neurons always fell short of reality -- as most models had assumed neurons stored a single state. This would imply neurons can store a good deal more than that and that the "range" of states is a lot more flexible.

poor reasoning (1)

inputdev (1252080) | more than 2 years ago | (#39455035)

Later, when exposed to triggering pulses of light in a completely different environment, the neurons involved in the fear memory switched on — and the mice quickly entered a defensive, immobile crouch.

This does not sound convincing to me at all - there could be many reasons for the mouse to become defensive, one of the least likely of which is that a specific memory was triggered...

Re:poor reasoning (2)

b4dc0d3r (1268512) | more than 2 years ago | (#39455943)

Luckily, you're dealing with Science, not armchair philosophers or youtube commentators. I appreciate your attempt at using logic, but don't trust the summary to explain everything. From the abstract, it seems Science has considered that you might have a point, and went back in time to address it.

The mice showed increased freezing only upon light stimulation, indicating light-induced fear memory recall. This freezing was not detected in non-fear-conditioned mice expressing ChR2 in a similar proportion of cells, nor in fear-conditioned mice with cells labelled by enhanced yellow fluorescent protein instead of ChR2. Finally, activation of cells labelled in a context not associated with fear did not evoke freezing in mice that were previously fear conditioned in a different context, suggesting that light-induced fear memory recall is context specific. Together, our findings indicate that activating a sparse but specific ensemble of hippocampal neurons that contribute to a memory engram is sufficient for the recall of that memory

Defensive crouch? (1)

Jmc23 (2353706) | more than 2 years ago | (#39455083)

Rats will go into a defensive crouch pretty much at any sudden unexpected stimulus. Put an electrode into a pleasure center and activate it and the rat will go into a defensive crouch. You see this all the time when shaping in skinner boxes.

It would be very hard to say that they were re-experiencing that specific memory.

This terrifies me... (1)

Last_Available_Usern (756093) | more than 2 years ago | (#39455135)

Next there will be weapons created that can literally immobilize you through fear. Funny, is this not exactly what the Scarecrow did in Batman?

Re:This terrifies me... (0)

Anonymous Coward | more than 2 years ago | (#39455503)

Fear is just the edge of this. it's easy to check to see if you got the right response. It sounds like a way to elicite emotional reactions through memory and, to an extent, control behavior. Want the troops angry? Check. Want to mask fear with something else? Check. Want the plebes happy? Check. Interesting in a totalitarian kind of way...

Re:This terrifies me... (1)

mikael (484) | more than 2 years ago | (#39455523)

That was hallucinigenics. Try and make the target see what they most feared. I'd have thought Batmans worst fear would to be tangled up in nets.

Descartes (1)

Empiric (675968) | more than 2 years ago | (#39458167)

Referring to the 17th-century French philosopher who wrote, "I think, therefore I am," Tonegawa says, "Rene Descartes didn't believe the mind can be studied as a natural science. He was wrong. This experimental method is the ultimate way of demonstrating that mind, like memory recall, is based on changes in matter."

Whoa, whoa, whoa. Hold on. The Mind-Body Problem isn't going down quite that easily.

This issue isn't whether the brain participates in mental phenomena (that's been clearly known since the first time a caveman hit another one in the head with a rock), but whether physical processes are sufficient in themselves to capture the range of capabilities of "mind". To support that, one would need to, on some level, show an equivalency of a broad set of mental abstraction to a set of brain processes. That is, basically, to be able to use the abstraction and the supposed brain mapping essentially interchangably for the purposes of description or logic.

Take, say, "freedom", as one of a broad range of "mental entities". It's insufficient to show, say, an EEG representation of a brain with an individual "thinking about freedom", and claim you've captured the content materially. Apart from the difficulties of teasing apart the concept itself from the feelings about it generated in his brain by the concept, his personal mental associations with it, associatable but not definitionally-equivalent memories, etc., which we cannot presently do on at minimum a technological level, there is a bigger issue here of whether this is even theoretically, or logically, possible--ever. Those neurochemical activities occurring when "contemplating freedom", even constraining ourselves to one particular individual, are -not- the same meaning and content as "freedom". If they were, we should be able to interchangeably say, "Ron Paul is for freedom" and "Ron Paul is for..." and hold up an EEG of test subject thinking about freedom, and have these two approaches be equivalent in content for all uses of the concept "freedom" in all contexts of discussion and logical inference. That is the criteria by which one could know they have fully and accurately mapped mental concepts to brain processes. In reality, this example fails right out of the gate, in that we would have, at best, the mapping for one or a few individuals (which, in the distinctions between the individual brains would break equivalence another way...), not something that could answer "point to a complete physical description of the concept 'freedom' as it exists in the world". Thinking of other possible examples of attempts to retain equivalence between the concept and the picture quickly make it clear claiming equivalence would be absurd, e.g. "Would you sacrifice that freedom for a million dollars?". Hence, they are not equivalent, and a physical mapping cannot be claimed for at least a broad class of this type of mental phenomena.

Really, this dilemma has been around for a couple thousand years in philosophy, and not because people didn't understand the brain was associated with mental processes, or had not investigated neurobiology to our current degree of breadth and specificity. The questions the Mind-Body Problem poses are not fundamentally technological and will not be solvable by that means, however headline-grabbing finding another thinking-or-feeling associated process may be for neuroscience. Quite simply--"is associated with", materially in the brain, is not equivalent to "is", conceptually in the mind.

Lest I be accused of worldview bias here, here's a good overview [] , presented, incidentally, by a Professor of Philosophy who is also quite vocally atheist. Further references from over the last 2000 years of Western Philosophy, forwarded from people of all manner of metaphysical presuppositions, can be googled at will.

Help the soldiers forget... (0)

Anonymous Coward | more than 2 years ago | (#39458527)

Perhaps this can be used to extinguish the haunting memories of war veterans.

Creepy... (1)

JeffMings (12432) | more than 2 years ago | (#39459605)

This is simply creepy. Yes, there are potentially wonderful applications. There are also potentially horrendous ones. This is creepy.

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