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MIT Researchers Explore How Rats Think 136

Ant writes "A Nature News article explains that, after running a maze, rats mentally replay their actions backwards." From the article: "As the rats ran along the track, the nerve cells fired in a very specific sequence. This is not surprising, because certain cells in this region are known to be triggered when an animal passes through a particular spot in a space. But the researchers were taken aback by what they saw when the rats were resting. Then, the same brain cells replayed the sequence of electrical firing over and over, but in reverse and speeded up. 'It's absolutely original; no one has ever seen this before at all,' says Edvard Moser, who studies memory at the Norwegian University of Science and Technology in Trondheim."
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MIT Researchers Explore How Rats Think

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  • by hobotron ( 891379 ) on Monday February 13, 2006 @03:27AM (#14704087)

    If a rat knows the difference between a Stack and a Queue, you better start updating your resume.

  • .gnitseretni yrev siht dnuof I
  • If this idea proves true in people, it could have many implications for human learning. It suggests that those idle times, perhaps spent gazing into space, are actually crucial for our brains to replay, and learn from, recent experiences.
    Are dreams there only to help the learning process? Is there something more to them?
    • If this idea proves true in people.

      I'd be surprised if this proves true in people. Most people can't even remember where they parked their car.
    • Re:interesting... (Score:5, Insightful)

      by Skreems ( 598317 ) on Monday February 13, 2006 @05:03AM (#14704406) Homepage
      Most creative thinkers already understand, at least intuitively, that the human brain will continue working on a problem even when a person is actively thinking about something else. How many programmers know that when you're beating your head against a problem, a good way to solve it is to go do something physical or repetitive, like play sports or video games or even sleep? Then when you come back, your brain has an answer for you, or at least has conceptualized the problem so you can get a better handle on it.

      I don't know how much there is to officially back this up, but I think this is why OOP caught on so well, at least with some people. If you have a system made of interacting modular components, your brain doesn't have to conceptualize sections of some messy lines of ASM or C code... it can just use the constructs you've actually built into the system, so the "processing cost" of groking the system is much cheaper.
      • Yeah, that's spot on. I can still remember dreaming visually with Java object during a particularly heavy project.

        I thought at the time one could make a good VR programming environment - none of this silly lines of code stuff, instead you move classes and objects as visual structures (blocks if you like) so you can see exactly what is interacting with what.
      • I am one who has beat my head against a problem all day, went to sleep, and woke up with a working solution in mind. It's weird when that happens.
      • ... a good way to solve it is to go do something physical or repetitive, like play sports or video games or even sleep...

        Yeah, I guess that's why I keep coming back to /. at work.
      • I imagine that taking a break from a problem helps - not because you are thinking about the problem - but because when you return to the problem you don't have so many competing thoughts blocking your thinking. (The same theory can be used to explain the top-of-the-tongue effect.)
  • Interesting (Score:5, Insightful)

    by Belseth ( 835595 ) on Monday February 13, 2006 @03:35AM (#14704122)
    Sounds like it's a way of setting important memories. Being able to navigate a course is important to a rat's survival. It'd be interesting to see if this happens with all memories or just the most important for the rat to recall. Stress causes memories in humans to become more perminate. There was a study where people held their hand in ice cold water to see how it affected memory. The shock of the cold water increased retention dramatically. I'd be curious if the levels of stress hormones went up as well. Rerunning the memory may be a stress reaction to important information.
    • An interesting observation I made when studying for bigger exams:

      a) There are "key days", where I panic about not being able to learn stuff in time and those are the days when I remember/understand stuff far better than on self-confident days. On "panic days", I learn 3x-5x more effiently than on self-confident days.

      b) I might study a whole day long and dont understand or at least not being able to explain the formulas/problems/algorithms/whatever in my own words. And then I panic. When I have gone to sleep
      • An interesting observation I made when studying for bigger exams:
        Sometimes I remember the dreams of those nights being about formulas and exams.

        It pisses me off so much when I wake up dreaming about the problem I was working on the night before... as if work/school (same thing for me) has completely taken over my life.

        In fact, it stresses me out more to be "stumped" than to have a deadline. I have to wonder if this is a natural learning strategy for some people - if you don't understand somethi
    • Dominos Pizza will be hiring rats as delivery drivers. after i made a delivery and arrived at the destination, i used the same techniques as the rats use! i would literally replay the course backwards in my head, reversing all the turns, etc (while smoking a bowl). after a few months in that "profession", i could go into any new city and keep my bearings easily. since i am amazed by the powers and skills of many animals and insects, i am honored to know i can compete with a rat!
    • The only reason to do temporally reverse processing is, of course, error back propagation. The rat's logic and sensory data does not match 100%, and the difference is stored into special locations for later processing. When resting, rat uses this data, back propagates it through its network and adjusts the synaptic weights (weighted by the gradient of the neural responce) to obtain maximal behavioral change with minimal synaptic changes, ensuring locality of the behavior change. This is so obvious that I wo


    • This must happen in humans as well. Some years ago I did some studies into deaths at fires in buildings, as very few people used the well marked EXIT paths, but most ran in panic back through the way they came in. It was suggested that large crowd shows in theatres etc must enter people by the fire exit ways to ensure correct rapid exiting, but commercially this was not possible ( extra staff and entry points by-pasing the sales of extra stuff) and the fire authorities thought our results as "odd".

      This i
  • Evidence finally found to support conspiracy theorists' claims of rats plotting world domination.
    • Evidence finally found to support conspiracy theorists' claims of rats plotting world domination.
      But Brain, where are we going to find 500 dancing girls and a cubic meter of Silly Putty at this time of the night?
    • Evidence finally found to support conspiracy theorists' claims of rats plotting world domination.

      Plotting? They have already acieved it! the species is called Rattus Politicianus, you it infests senate, parlieamentary and other government buildings world wide. There is also a lesser species called Rattus Lawyeriensis it is usually found chasing after ambulances or monitoring peoples internet connections looking for evidence of illegal music downloads.
  • by Anonymous Coward
    mouthgaurds in we're shaking hands now!
    Can they induce the maze path into the mouse?
  • by TubeSteak ( 669689 ) on Monday February 13, 2006 @03:39AM (#14704140) Journal
    The discovery could also help to explain why people tend to learn a new task quicker when they take short rests between each practice round. It suggests that eliminating such breaks could actually interfere with learning, and perhaps even explain why hyperactive children often have learning difficulties.
    This may be less about ADD/ADHD kids than about teaching style in general.

    Any teaching style that will appeal to a hyperactive child, will more than likely be engaging for a 'normal' student.

    Though it might be a stretch to suggest this could be extended to understanding hyperactive kids. AFAIK, they usually have abnormally low levels of dopamine and/or seratonin in their brains, while the article posits that "The rerun [for mice] could coincide with a burst of the reward chemical dopamine, which is released in the brain when the animal finds food."

    Maybe they can find some hyperactive mice to run the tests on?
    • Back when I was I kid there was a very good treatment for ADHD. You lack attention in school and your mother opens a large can of whoop-ass on you. Voila! You don't lack attention anymore (until your ass stops hurting at least). To me this seems like a better alternative to stuffing kids with psychotropic drugs.
    • You do realise that hyperactivity is just one optional symptom of ADD/ADHD? Using the word "hyperactive" is missleading, since it's the attention span issues that are the hallmark of the disorder. I assume you already know this, since you used the term ADD, but many others don't know.
  • by neoform ( 551705 ) <> on Monday February 13, 2006 @03:40AM (#14704144) Homepage
    It's pretty simple, once they get the juice on someone, they squeal to the nearest narc.. obviously.
  • "It's absolutely original; no one has ever seen this before at all," says Edvard Moser.

    Except for the rats, of course.
  • by ( 142825 ) on Monday February 13, 2006 @04:13AM (#14704266) Homepage
    MIT is studying politicians. They use rats since the rats won't pick the scientist's when they turn their backs.
    • hejdig.

      Why this hasn't been discovered earlier is because these experiments are ususally done on politicians - there are no animal rights group, or any other group, fighting for their fair treatment.

      And since these experiments have only been done on politicians earlier no previous experiments have shown any brain activity ever comtemplating earlier decisions.

  • The researchers found that some of the rats thought more about the maze than others. Here []'s a picture of two mice. The one on the left thought much more about his performance than the one on the right.
  • I read this article twice and tried to come up with a good comment. But all that happened was that the words kept repeating themselves in my mind...

    ... and just think how many times you, my dear reader, will have to repeat this sentence in you mind. So stop resting and get back to work!
  • by icecow ( 764255 ) on Monday February 13, 2006 @05:11AM (#14704428)
    Haven't most people walked through the halls of a unfamiliar building to their destination then stopped and reviewed how to get back out a few times (a movie in reverse sorta) in order to get it in their long term memory? or is it just me? I don't always do it, just when the path seemed complicated. I'd think doing this would be much more important to a mouse considering they have rival creatures towering over them like downtown buildings.

    Whoa, I'm reading back my post and thinking WTF!
    • I'm sorry.
      (Not really)
    • Thinking "backwards" always fucks me up. I get my directions flipped and just end up confusing myself even more. I've either got to start from a landmark of some sort, or right from the beginning and retrace my steps that way.

      Though I guess its worth nothing that i'm also one of those people who sucks at reading the alphabet backwards. And if i'm ever quizzed on "what letter comes before..." I generally have to pick a 'landmark' string of letters ('lmnop' seems to be easiest, dont ask me why) and quickly
    • I do that too - after going through a junction, look back and see which direction to take (two adjacent T-junctions with staircases are probably the hardest).

      I've also noticed that when taking a new route for the first time, such as finding a room in a campus build never visited before, the outgoing path always seems twice as long as the return path.

      There was an article about how London taxi drivers had larger hippocampi regions>/a> when compared to non-taxi drivers. []
    • Haven't most people walked through the halls of a unfamiliar building to their destination then stopped and reviewed how to get back out a few times (a movie in reverse sorta) in order to get it in their long term memory? or is it just me?

      I suspect there are different mechanisms at play here.

      This is morking with a documented phenomena with rats whereby they will take the same route to/from a location over and over, moreso than most other critters.

      It sounds like this goes some way to dexcribing the mechanism

  • Well... (Score:1, Funny)

    by Anonymous Coward
    overlords rat thinking backwards new out welcome, one for I.
  • can we get the Toxoplasma [] to change their 'memories'?
  • Why bother what they thinking anyway? Even us (human @ homosapien) can't think what others think..they need to research that. After all the test and research using them as the test object?
  • by S3D ( 745318 ) on Monday February 13, 2006 @06:18AM (#14704618)
    The result is also of keen interest to those who study artificial intelligence and try to teach computer systems or robots to learn through reward and punishment. Some such systems already work by playing back a sequence of moves so that the computer can identify at which point it made the trial or error.
    It's called back propagation learning [] The algortihm is based on the error propagation backwards from the output nodes to the inner nodes of neural net.
    • It could also mean g?method=22 [] (Wikipedia itself is currently down). Reinforcement Learning (RL) is about learning from reward - and about finding optimal sequences of action. Especially for learning sequences over time - like the rats - it is THE method of choice. And yes, Artificial Neural Networks (ANNs) are often used for representing the "optimal policy" in RL. The weights in those networks are then altered by the RL process.

      You could describe the proc
    • I very much doubt that a biological brain works in AT ALL the same manner. Information in biological neural nets appears to be pulse and time coded, whereas a feedforward network operates independently of time and processes real-valued signals, not discrete activations. In fact, once trained, a feedforward network corresponds exactly to a nonlinear, continuous, differentiable function.

      The biological brain is not just a function.

  • Sounds like a lovely way to learn how actions lead to rewards without the complications of the actor-critic approach. I'd like to see whether this learning is able to propagate the rewards backwards in a way that allows a change in reward to affect actions. At the same time, I'd like to know whether this can be used to learn the continuous dependence of the final rewards on the actions chosen. Finally, I'd like to know whether this reversal is more general--that is, can plans be reversed? If so, it provide
    • This kind of temporal difference learning is the job of the cerebellum (short time scales) and the basil ganglia (arbitrary time scales). I would bet that the fact that the sequence is replayed backwards in this case is just arbitrary. The idea is to re-enforce the connections between the neurons that represent the learned sequence, as well possibly to train cortical neurons in gestalt like representions of the sequence.

      You are right in that this type of sequencial inforamtion is capable of encoding causa
      • I would bet that the fact that the sequence is replayed backwards in this case is just arbitrary.

        Maybe not; don't bees, returning to the hive after locating a juicy pollen spot, do a "dance" that teaches the other bees the location, but the dance is in reverse? I will try to find a reference.
        • I mean arbitray in the sense that if you were designing a hippocampus to support sequence retention you could design it either way. The connections between cells that represent elements in the sequence need to be re-enforced by repetitive activation. I guess this would be what the rat is doing while resting.

          Then again, there's spike timing dependent plasticity (STDP) to consider. I'm not sure how this is effected by the sequence being played in reverse. The hippocampus does seem to be multimodal (learni
  • wouldn't it make more sense to study the moose?
  • The paper is available at Nature Advance Online Publications [] - if you have access.
  • Oh okay gotta turn left,gotta turn left ..... nope maybe it was right, yep right it was right ..... this looks familiar. Ok two lefts now and then a another right ..... oh yeah, now i can smell it. Just a little bit further .... a quarter turn left followed by a hard 180 degree right .... I can totally taste it now!! Here i come .... just a few more turns and that sweet reward is mine!!

    I don't even care that this is the fourth time this morning, this never gets old. I wouldn't mind a glass of milk
  • common trait (Score:2, Interesting)

    by recharged95 ( 782975 )
    Most animals are path oriented. Could be why cats & dogs can find their way 'home'. When taking our cats for a walk (yes, on a leash) into a new area, they always stay on a path. If we turn around, they pull us towards that same route back to the car (cause they want to go home...). And when they walk back appear more confident in stride. Considering rats are more intelligent, this theory does have traction.

    Of course, it doesn't take a MIT researcher to figure that out, just funding and identification

  • It seems like this could be the next step in reading minds, sorta. There have been stories about the new advanced lie detectors "reading your mind" in a way already. If they can nail down what is going on during those nerve replays, it would really just be a matter of getting a person to trigger those replays in their minds and record them. Granted, I think this is probably a long way off, but you know someone with the knowhow is probably already thinking the same thing. This could also have interesting
    • There was a recent Robin Williams movie like that, actually. The consequences of having such a device are quite startling. (moral responsibility) "The Final Cut" is the name of the film.
      • Wow...thanks. The movie looks pretty interesting. I am going to have to pick it up sometime. Coarse I will also say that I am going to hunt you down if it creeps me out too much. Seen a few of those wierd future things that just creep me out...makes me think someone needs to go bury the writers before they give anyone any nasty ideas. :)
  • The real goal of these experiments: How women think.

    With the dating and the lipstick and the slaps in the face, hoy-vn-fra-gn!
  • This is a duplicative effort. It is already being studied in Utah. There is an extensive case study going on ... I think it is called SCO v. IBM. And there are at least three related studies called SCO v. Novell, SCO v. Redhat, and finally, SCO v. DaimlerChrysler.

    The studies seem to be quite comprehensive and even may shed some light on a rat variant that is pervasive in Washington state. But it is known that those rats are a bit more deceptive and may be able to escape the spotlight in these studies.

  • How Rats think... (Score:1, Redundant)

    by digitaldc ( 879047 ) *
    1) Find cheese
    2) Eat
    3) Reproduce
    4) Find burrow and Sleep
    5) Return to procedure 1)
  • Poetry like, say, "Shed Reading (Rattus Norvegicus) []" by Black Flag, in which an expressive rat bemoans his fate.
  • Rats don't think because they don't have to, here in the UK anyway. They operate on the taxi-rank prinicple, i.e., they are compelled to take the first client who knocks on their door.

    Just a little spot on Monday morning humour...

  • Im to expert in neural networks but don't they use a technique called back propagation for refineing the connection between nodes... it seems to me that these rats brains must be using a similar technique? Does anyone know if research like this is being used to better neural nets in AI?
    • It seems more to me that it's going through its existing knowledge, trying to remember something. Backpropagation deals more with refining memories. Plus, this is unsupervised, not supervised learning, so I wouldn't think there would be any backpropagation.

      I do wonder though, how this corresponds to associative memory. Maybe something is going on that's similar to adaptive resonance theory.

  • Then, the same brain cells replayed the sequence of electrical firing over and over, but in reverse and speeded up.

    Benny Hill was unavailable for comment.

  • New Science? (Score:4, Informative)

    by ThePopeLayton ( 868042 ) on Monday February 13, 2006 @11:46AM (#14706447)
    Sorry boys, But I have been studying Neuroscience for the last 3 years. Every lecture we have had on sleep, particullary REM, has taught that when you are sleeping your neurons will all re-fire in an organized manner. This is when your memories are "consolidated" from semi-long term to long term memories. This is why if you have had a particularly stressful day you can "re-live" that day in your dreams. However it has long been shown that "place cells" or neurons that store spatial location will fire in the direct same sequence in which they fired when the test subject was presented with a spatial puzzle. You can read about this in the book Neuroscience by Kandal.
  • a) researchers wired some rats and made them run up and down a straight run and watched some nerve cells fire;

    b) researchers saw the same nerve cells activate in reverse order while the rats rested;

    c) researchers speculate either wildly or obviously that the rats are replaying the event and that maybe the rats are mentally replaying the run, and that maybe it would be the same in a maze, and maybe this coincides with dopamine release (not observed or measured), and that if maybe that were so, it would maybe
  • ...always trying to get back to the cheese(unapologetic, anti-competitive, monopoly position).
  • "MIT Researchers Explore How Rats Think"

    The people in the White House are upset over the invasion of privacy!
  • If I'm wandering around an area thats new to me, ok I usually get lost, but before then I am physically retracing my steps in reverse. I follow the familiar landmarks, buildings whatever as i return to my starting point. I don't see whats so astounding that another animal would be hardwired to follow a simialar process to retrace its steps. I mean the rat probably has much more difficultly with visualizing a maze as a whole, it would be wasting its time thinking about how it got to every single point in its
  • So, we now know that rats can think.

    But why test rats? It's way more important to know if politicians and higher management types can think. Is this feat within their reach? Or are they, as we unscientifically suspect, completely braindead?

    Inquiring minds want to know!
  • They don't really think so much as they run for office.
  • My bet is they're trying to figure out what the Prime Minister of Australia [] will do next.
  • Well, duh, how else are they supposed to know how to get out?
  • Lewis Carroll said it best...

    `I don't understand you,' said Alice. `It's dreadfully confusing!'
    `That's the effect of living backwards,' the Queen said kindly: `it always makes one a little giddy at first --'
    `Living backwards!' Alice repeated in great astonishment. `I never heard of such a thing!'
    `-- but there's one great advantage in it, that one's memory works both ways.'
    `I'm sure mine only works one way,' Alice remarked. `I can't remember things before they happen.'
    `It's a poor sort of memory that only wo
  • OK, lets think about this.
    A rat in the real world (e.g. my shed) routinely goes out from where it lives to scavenge food. This creature has a home base and returns there. From an evolutionary point of view I imagine there would be strong selection pressures to be able to return to it's home and not get lost and end up with the neighbours cat. As such, when the rat gets to the food it's brain would want to be primed for the return trip, which is most likely in recent memory and not committed to long term mem

Adding manpower to a late software project makes it later. -- F. Brooks, "The Mythical Man-Month"