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Eternal Sunshine of the Spotless Rat

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What is a memory? Science writer Jonah Lehrer tells us is it’s a physical thing in the brain… not some ephemeral flash. It’s a concrete thing made of matter. And NYU neuroscientist Joe LeDoux, who studies fear memories in rats, tells us how with a one shock, one tone, and one drug injection, you can bust up this piece of matter, and prevent a rat from every making a memory. LeDoux’s research goes sci-fi, when he and his colleague Karim Nader start trying to erase memories. And Nader applies this research to humans suffering from PTSD.


Joe LeDoux, Jonah Lehrer and Karim Nader

Comments [41]

Peter from St. Louis, MO

Is that all memory is a protein/chemical response that is recreated each time? Is there something more to the brain than just memory? Are reason, morality, conscientiousness different than memory? How do I intrinsically know that stealing or murder is wrong? This story suggests I recreate that memory/feeling of "wrongness" each time I think about it.

Also the Radiolab episode "Limits" form April 05, 2010 spoke of a man named Mr. S who had a phenomenal memory. I know that story has been updated and corrected, but he still had a great memory. How does he do it. Does he have better proteins? Just wondering.

Jul. 07 2015 12:26 PM
Jared Dulmage from Los Angeles, CA

I have to agree with many of the other commentators that the assertion that repetition degrades memory seems counter-intuitive and counter to experience, education and training.
On a darker side, the ability to chemically disrupt memories, even established ones, sounds like a path to dystopia. It's very disturbing to imagine being involuntarily made to forget an incriminating secret, a breakthrough invention, or some special motivation at the whim of a powerful and unscrupulous competitor. The "Men in Black" neuralyzer gone terribly wrong.

Jul. 02 2015 01:56 AM
bo0bbi1 from mexico

hy erubudy huw iz yo tudwy?

Oct. 27 2014 11:43 AM

Jad, you need to go further on this one too. The problem is NOT (not really) that "memory is malleable". It's that all of consciousness in spontaneous fabrication. If you look closely the mind does NOT (not actually) have any information "input/output" devices. It only has sensory devices from which it **invents** **suggestions** and then re-invents a plausible (to itself)story from.

Conscious reality isn't reality, never was. It's always a complete fabrication! Of course... you still have the problem that the world works somehow, and the problem that it's still unlikely that you'll talk to me to find out what I know....

Aug. 02 2014 06:41 PM
stanley b klein from ucsb

Memory is not simply physical brain activity. Memory is an experience. Neuroscience conveniently (how else to query non-linguistic beings?) ignores that and focuses on some of the potentially physical aspects that go into making memory an experience. They then (psychology is guilty of this a well) adopt a simplistic causal model (memory is stored experience from one's past that subsequently is retrieved to influence thought and/or behavior). Of course, by this simplistic assertion, almost all cortical function terminates in memory (imagination, belief, thought....) save for strictly regulative activity. And the word memory becomes a meaningless designation.

Memory is the experience of stored (often greatly modified content), not, as psychology will tell you, the content experienced.

Radiolab needs to get some actual memory experts on the show -- though they would need to pick carefully, lest they continue to propagate pop conceptions of topics like self and memory.

I expect more from PBS.

Jul. 31 2014 11:53 AM
Elan' from Los Angeles

The way that the drug is used on patients sounds a lot like PSTEC therapy.

Jun. 25 2013 05:07 PM
Lois from Philadelphia

Is Clive as close to God as human can get? Completely living in "the now"? It also makes me have to ask the question what does the Bible mean when it says "sing a new song"? What sets creativity apart in the human mind? The spirit? Why does it seem like it always comes back to moments of letting go to what we think we know and diving into the possible reality that when we are true to our creativity and treat every moment as if it is the only moment that exists, we can truly find fulfillment and we don't even have to think...we just do, and it seems so clear and flawless.
Or what about the painter? He stopped painting for anyone but himself to have a creative release. Through that, there was some kind of healing. Is it spirit? Is spirit what heals, what connects us, what frees us from the neurological mind? Where the memories, the images, the sounds and songs...was the beauty forgotten in the memory? But, possibly when we connect to our creativity it could take us back to the pure goodness of...well, life. God.

Jan. 22 2013 11:48 AM
Ana Maria Pico from Puerto Rico

Very interesting and I loved the way it was presented. But I agree with previous comments : what really makes you remember something? Why math is always the same? I think that we are more than proteins, we are elecrtromagnetic fields and information is stored some other way. I suggest seeing the movie "The Living Matrix", you can google it and get it in internet. Other scientist have aomething to add to this discussion.

Nov. 11 2012 05:47 PM
Katherine from NYC

As an educator, I'm having a hard time wrapping my mind around what this segment is arguing. If you recreate a memory every time you recall it, then what are the implications for learning? For example, every time I remember that 4 times 5 is 20, is this memory being "recreated" and changed slightly every time I remember this? As several people mention, it seems hard to conceive as memories being recreated each time you recall them and therefore being changed each time; and I think this is because there is no clear distinction made in this segment between what constitutes a memory and what constitutes knowledge. In my conception (as an educator), the two are inexorably linked, but perhaps the show is using the word "memory" to refer only to emotional memories. It would have been helpful for the producers to make it clearer what is meant by "memory" and to explain how this relates to knowledge.

Nov. 09 2012 02:36 AM

Very interesting show but I was just wondering - is it not possible that long term stored memories and recreated memories are distinct and different but that this drug affects them both? It seems like a bit of a leap to say that because this drug blocks new memory formation and memory recollection the two are the same. Could they could be really similar processes involving similar proteins which are both blocked by the drug?

Mar. 20 2012 07:29 AM

Radiolab linked to the info on the drug used to ease traumatic memories: propranalol, a blood pressure drug. This is the scientist:

Thanks Radiolab!

Mar. 18 2012 03:30 PM
Coral from Portland

Like i wrote in your comment section: "RE-play. The fact that people, "scientists" would rather fuck around messing with the sensetivities of innocent animals, rather than spending that time learning how to be quality human beings makes me sick."
I'm pissed,that you would even entertain the idea of enabling this kind of behavior towards animals by including it in your radio show ,in such a way, no matter what the 'justifications' are. I am disgusted, by this; and humans's feeling of entitlement towards,relying on animals to quench,their inine curiosity,and validate their college degrees and self worth.
If people would spend the time they do harrassing innocent animals and grow some balls, maybe they would actually,get people,to mourn and heal traumas from the past,like humans are supposed to do, rather than sidestepping,those issues ,and extending uneccesary suffering by projecting it on animals.

Feb. 23 2012 12:08 AM
Coral Clearwater from Portland

RE-play. The fact that people, "scientists" would rather fuck around messing with the sensetivities of innocent animals, rather than spending that time learning how to be quality human beings makes me sick.

Feb. 22 2012 11:38 PM
Ashley from New Jersey

This piece was not one that I particularly enjoyed. Although I can appreciate it on an artistic level. This is because of the fact they used the associative structure in a unique way. They related the idea of memory to not only animals, but to technology and present day.

Dec. 19 2011 11:40 PM
Suzie from NYC

Radio Lab is the greatest!
To me memories are more emotional than the sights and sounds of something. What we remember is the emotion, and we don't all experience the same emotion for the same event, so why would we 'remember' it the same way. What's the phrase "distance make the heart grow fonder" I think our emotions change regarding events in the past to fit our needs today.

Nov. 13 2011 04:02 PM

Hey, I know this is a relatively old episode (and hopefully you remember it) but I only just discovered the show (which rocks).

I was hoping you would cover a question on the topic of the "forget-me-drug " but it wasn't mentioned. So...

What if I wanted to forget a traumatic memory and was in the doctor's office recalling the memory as they administered the drug and then suddenly! something unexpected were to happen that caused me to remember something wonderful? Take for example, my phone were to receive a text message, playing the Metal Gear Solid Codec sound that I installed and then triggered me to remember how much I love Metal Gear Solid. What would happen to my love of the game?

Jun. 13 2011 05:29 AM
Ala Navratil from Auburn, CA

Really interesting.

May. 02 2011 04:02 PM
Marisano from Davis, California

Concerning the recreation of memory and the missing Platonic template, I think the program was just driving home the point that memories are not immutable - the fact that you can forget is testament to that! Maybe a better way of think of recreating memories is to consider the blind spot of one of your eyes. Your brain happily fills in the "details" of something that falls onto the blind spot depending on the current visual context. Only, maybe with most memories there are very many blind spots, more of them than there are 'fixed points' (because most often for these kinds of memories, minute details are not important), and maybe even some of the fixed points can be changed. [The shape and functioning of proteins can certainly change in time.]

From a biological standpoint, the purpose of a memory is not simply to be remembered for its own sake, or even to define you, it's to help you to survive and/or to better your position. In light of this, it may often be quite adaptive to recast memories in terms of the here and now.

Feb. 10 2011 01:56 AM
Marisano from Davis, California

About the couple and the kiss, I don't think that such a memory, even if re-embellished each time it is recalled, will necessary diverge between a couple. That is because that couple are sharing experiences - emotional and otherwise - all the time. So if they have any kind of connection with one another that, perhaps incorrectly reestablished, memory is not likely to diverge endlessly from that of their partner. Think of it as genetic drift versus convergent evolution. The researchers were describing a memory apart from a shared context - a genetic drift scenario, but a (good) couple is likely to have a lot in common, so their separate versions of the kiss may also have a lot in common, certainly in overall meaning.

Feb. 10 2011 01:36 AM
Greg from North Platte, NE

It seems people that don't agree with this episode (recreating the memory each time) refer to words and numbers.There is an obvious difference. Example, if a quote from Shakespere, as with the multiplication table are altered in any way ---those around you will point out the misquote or error (3x5=16?) right away. This will reinforce a correct recollection. Everytime.

Listening to this episode I notice that it refers to more abstract memories (events, people, places).Here it seems to easily be re-created. Did the man have an orange shirt, or was it an orange blazer. Now add a second person, or third --- all have memories that will differ. For me, this is demonstrated every Thanksgiving with the same recollections everytime. I must correct them. Why me? I have the pictures to prove it.

Jan. 30 2011 11:10 PM
Nona Calingasan from Philippines

Where does the brain get the memory to recreate? If remembering means recreating then there must be a basis of that recollection, right?

Jan. 21 2011 07:26 PM
Julia Ingram from Portland, Or

I'm a hypnotherapist, specializing in anxiety disorders, especially panic attacks and phobias. I have a client who daily creates memories of mythic proportions by imagining the worst thing that could happen. The way she avoids constant panic attacks is by staying within one mile of her home. In other words she now has agoraphobia. This show gave us another healing avenue to explore, and has given us both hope that there's a way to ease or even rid her of daily suffering.

May. 20 2009 05:41 PM
gilrdebord from wooster, ohio

This episode of Radiolab was my very first. Since, I have incorporated your program into my daily work routine. At 4:00, with an hour to go until my release, I grab a cup of terribly weak coffee from the finance guys across the hall and listen to an episode. That last hour is the most wonderful hour of my work day. I have an incredibly short term auditory memory and so repeat or not, I'm all ears and scribbling pen. I appreciate your work.


a brainsteam with a body sitting in front of a computer in wooster, ohio

Nov. 07 2007 02:28 PM

Something about this episode bothered me.

The point is made over and over that the mind is not a file cabinet. We do not store master copies of our memories; we create them when we remember them.
They say that a memory degrades the more we remember it.

But it makes no sense to say we recreate the memory each time because there must be some information in our brains that maintains the connection between the actual event and our recollection of it.

For example:

Yesterday I meet a man with an orange shirt.

Today I remember the experience as meeting a man with an orange suit.

Years from now, I remember meeting a man with an orange hat.

All of this can follow from a process where I create a new memory and muddle the details over time.

But how can these recollections be in any way similar if there isn't some stored data that supplies the source material for the new memory I'm creating?

I mean, how else can I correctly maintain the memory of meeting a man and not a woman?

If I am truly creating a new memory each time - what's to stop me from remembering meeting a woman who hits me in the face with a rubber chicken?

Surely some kind of master record must be supplying the framework of what I am remembering - even if I can't access it directly. Even if I distort this data over time, mustn't I retain some kind of starting point?

Oct. 10 2007 11:08 AM
Myra Chang from here

I like the information given and research done.
There is so much to know about this sugject and am pleased to know that you are playing a pivotal role.
How is the raining in Austin? Mom

Aug. 17 2007 06:15 PM
Vaclav from Prague, Czech Republic

My tutor used this show for our listening activity. We didn't do the whole thing, but the segment we did was so good that I can't wait to listen to the rest (necessery to add that listening is by no means my favorite activity).Lily, you're right, the show really makes science accessible to laymen...Thank you, WNYC!

Aug. 09 2007 06:51 AM
Bill from Colorado

The implications of this research (especially regarding the plasticity of re-remembered inputs), are staggering. I am thinking of the potent effects of re-imaging news events, and the power of spin professionals. Repetition of reported events with incremental changes in the framing or commentary can have a huge effect on the collective recall of our media saturated psyche.

Aug. 04 2007 06:06 PM

To David-

I would imagine that memories in human beings are a little more complex than those in rats, and associated with many other things (Obvious maybe, but still important). Especially if it's a memory that someone has lived with for decades.

Take that passage of Shakespeare. You've lived with it, recalled it in varied circumstances, and it's become intertwined with those circumstances. Maybe you remembered it at a party, and one of the lines will always be intertwined with that party. Maybe you remembered it in a trivia contest, and therefore it will always be intertwined with that contest. And on, and on, and on. So if you're remembering it when you take that drug, you're not going to erase it completely, because you're still going to have those side associations.

You might remember the words, or not, with the drug, but the connections you make will be lessened.

I think, also, it could be explained that you *don't* have that base memory of text or multiplication tables, just the neuronal pathways you use for memorization become reinforced every time you recall the lines of the dialogue or tables, which can be quite often.

Aug. 03 2007 03:23 PM
Matt Midboe from Dallas, TX

Great show, as usual. I caught it on KERA today. I'd love to hear a segment on how eidetic memory works, or if it is even real. Eidetic memory doesn't seem to alter with recall, or be alterable by others.

Aug. 03 2007 03:19 PM

One of my old professors studied memory, and he discussed an interesting thing: social memory. They did studies on couples who stayed together for 50 years as compared to those who stayed together for 10 or 15 and then split. The former couples had more memories of their former lives than did the ones who had separated.

Imaginative false-ish ones, perhaps, but still more.

Plus, though it might be that I'm generating a new memory every time I think of something painful, I think I still agree with Robert, because thinking about that memory has shaped who I am today, and I'd be a different person if I stopped remembering it as a painful experience that I may have learned from.

I know therapy works on the same issues, but at least I'm actively trying to reshape my mental map, and not having it done *to* me with a drug. Subtle difference, perhaps, but important to me. I can't even imagine what it would be like to be a Holocaust survivor and have those stark thoughts of human existence be lessened.

One interesting thing you mentioned in the program was that memories were less of a concrete thing and more of "you," at that moment, remembering. But what does that mean, then, about what "you" are? What is "you" if not memories?

Aug. 03 2007 03:13 PM
Illia from Tampa, FL


Your comment about the protein synthesis only reducing fear is absolutely correct. The link to LeDoux's lab expands the explanation. Their work is done within the amygdala which is the primal emotional seat of our brain and our fear reaction originates here. Since they only stimulated protein synthesis in this region, the fear associated with the memory NOT the memory itself was eradicated.
I liked your metaphor of the multiplication table as a way of thinking about our long term memory and the way we use it.

Jul. 31 2007 03:17 PM
Miguel Marcos from Madrid, Spain

As usual, a fantastic show. Thought I would share this: researchers at MIT have identified the molecular structure that leads to fear and have successfully suppressed it in mice. This appears to be a more direct method than that used by Karim Nader.

Regardless of the approach, however, it is fascinating, enticing, and disturbing, all at the same time.

Jul. 19 2007 04:36 PM
David from Boston, MA

I heard the show on WBUR. It was really interesting but it didn't make sense. Here's why.

In the rat experiment, they can't tell you what they are remembering or not remebering. However the patient in Canada, she was able to remember her trauma after being given the drug, she simply wasn't as affected by it emotionally. So maybe the rat remembers, but simply isn't afraid anymore. The drug erases the trauma associated with the memory. The rat remembers the tone is followed by a shock, but has not emotional (fear) attatchment to that memory.

Now as for each time you remember something you are creating a new memory, that doens't work either. I read a passage in Shakespeare and I memorize it. If I remember the passage each day it stays fresh in my mind and accurate. If I don't think of it for many years I'd be lucky to be able to recall it accurately at all. Unlike the kiss example given in the show this is the exact opposite outcome. Look at multiplication tables... There has to be a fundamental memory that you draw on to remember something. That base memory may fade over time, but it's there, you don't create it anew each time you remember it.

Jul. 06 2007 10:56 PM
Radio Lab

Hi Nathalia,

If you have questions about using Radio Lab material in the classroom just shoot us an e-mail at Thanks for listening!

Radio Lab

Jun. 28 2007 11:41 AM
nathalia from NYC

I sent the audio of the program to my sister un Argentina, she is a Psicology Proffessor at Mar del Plata University of Psicology, and she loved the program an the topic. She asked me if here is anyway that she could have the entire program written down to gave it to her students. Please let me know. Thks

Jun. 22 2007 01:47 PM
Emily from Cleveland, OH

This show was re-played on WCPN in Cleveland this morning, and it was one of those that made me late for work because I couldn't stand to turn the radio off before the program was over. We hit a break in the program, and I immediately found the audio file online so I could listen to the rest of the program.

What a fantastic topic, explored in so many ways... movies, art, music, science, emotion. Great job, as always.

Jun. 21 2007 09:58 AM
Norman Costa from Poughkeepsie, NY 12601

I caught a portion of your broadcast on memory while in my car. FASCINATING! I teach research psychology and other psychology courses. I will be directing my students to your .MP3 file for download. You combined good science with excellent communication. You made it accessible to intelligent people without dumbing down the content.

Norman Costa

Jun. 14 2007 07:53 PM
Juliet Seignious from Cortlandt Manor, NY

Todays show a knockout. Sending this in case you did not receive my other email. I love the show.

Jun. 14 2007 04:17 PM
Juliet Seignious from Cortlandt Manor, NY

I am totally in awe about your program. What I especially love about it, is the information you give about human nature, and todays program, about memory, was absolutely absorbing.. I was so throughly engrossed, especially because I could relate to those moments of lost memory. But this only happens when I am painting. So I am not yet worried about this circumstance. I get really create wonderful paintings in those moments.

Keep up the great job, and thank your producters. I do hope that you are continuing this program. I always feel that I am learning something new and interesting. Not enough of that in this day and age. So, Thank you.

Jun. 14 2007 04:15 PM
Martin from Brooklyn, NY

Loved the editing and presentation of this most important topic. Downloaded the audio file. However, I don't believe that the entire show was included in the nice audio provided.

PLEASE put the rest of the audio for download!

Thank you.

Jun. 13 2007 09:04 AM
Lili from nyc

This is such an amazing show. I love how accessible this show makes science for laymen.

Jun. 09 2007 11:03 AM

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