My first kiss. The first time I saw my first-born. When I knew I passed my PhD exam. Those exquisite moments in time. It turns out, I- and you- can relive those moments. Because they are encoded in specific cells in our brain.
Dr. Susumus Tonegwa of MIT led a research group (Drs. Liu, Ramirez, Pang, Puryear, Govindarajan of MIT and Dr. Deisseroth of Stanford) that proved this fact, publishing their results in Nature. And, they did so using a relatively new science termed optogenetics (pioneered by Dr. Karl Deisseroth, who was part of this team). This was highlighted as the technique of the year in 2010 (the science was first considered thus around 2005)- using fast light-activated enzymes to manipulate biochemical and electrical events in living animals.
These are called memory engrams by neuroscientists- but until this paper, it was not clear if they were artifacts or truly related to physical neural networks. Tonegawa proved that these memories reside in specific neural cells, and that these cells can be activated to recall the memory.
Memory engrams were first considered by Dr. Penfield, who operated on epileptic patients. He removed the portions of the brain which caused seizures. And, to insure that he only removed the cells necessary, he excited the brain with jolts of electricity, while the patients were under anesthesia. The subjects recalled various memories – even though a small number of neurons in the hippocampus were stimulated.
In this study, Tonegawa’s group identified which cells within the hippocampus were active when the mice were learning new concepts. Knowing which genes were activated in the cells, they coupled them with ChRS (channelrhodopsin 2), a light-activated compound often used in optogenetic studies. Using tiny optical fibers, pulses of light were delivered to the neurons that were activated, and then a mild electrical shock was applied to the same cells (which meant the mice would be afraid of this new learning concept). These cells were tagged with ChR2. If those same pulses of light were administered- with a different learning environment- the mice still responded with fear to this new environment.
This proves that reactivating neurons that are/were active during learning can reproduce that learned behavior.
But, we should be cognizant that memories may not form if we are under constant stress. Stress hormones (such as adrenal corticosterone) affect our prefrontal cortex- the portion of our brain involved with decision making and working memory.
Dr. Zhen Yan (SUNY Buffalo) (along with Drs. Yuen, Wei, Liu, Zhong and Li) performed studies on young (adolescent) rats, subjecting them to repeated stress. It turns out the stress impedes glutamate receptors, which have a critical role in prefrontal cortex activities. These results were published in Neuron. (You can also find the article here.)
The choice of adolescence was made because during this age, the prefrontal cortex is subject to rapid development. And, it’s not just region dependent, but a function of the duration and intensity of the stressor. A small amount of stress can improve learning, but severe stress or long term stress impairs the ability to learn. (You can read my recent article about stress here.)
So, if we want our brains to be able to imprint these memories- the ones we want to recall- we need to insure that we alleviate the stress in our lives.
You know what I think about when I read this….is this a potential break through that might also help people with PTSD eventually? The memories imprinted cause sudden and usually violent flashbacks to uncomfortable memories and times. I could see this new information being used to either counteract those flashbacks either with positive memory imprints or to reduce or deaden some of those more painful memories. Also, I guess I can see it being used in alzheimer’s research. This is an amazing discovery!
The stress portion of the article also is interesting. There is a common complain among the bereaved (widow/ers especially) called “Widow brain”. That for months after a loss their short term memory is is impaired terribly. It is a very painful and very real part of loss, so much so that I’ve gotten many emails with the complaint. I always advise people to carry paper and pen and write things down to help combat the frustration. Will be sharing this to help people understand they aren’t crazy, it is normal.
Great post!
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Widow brain is stress related, Lisa. PTSD could very well be stress related- but more related to the imprinting- and recall- of bad memories. I’m not sure we want to wipe those slates clean, but maybe…
Roy
I don’t think wiping the slates clean would be a good idea. I’m sure you don’t either. Good or bad all that we have experienced informs and forms who we are and become…developing meds or treatments to help dull some of the trauma in way they can deal with it better that would be a great thing. I think it might be possible with this new research. Perhaps not in my lifetime, but then again who knows. It’s a good hope for the future none the less.
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If we could selectively wipe clean our sltaes, there are a lot of benefits, Lisa. Completely wiping the slates clean is what politicians do when they say they don’t recall..
Easier said than done with the less stress concept; however, enjoyed the article on memory attainment.
Aw, come on, PeggyLee, bet you can control it!
R
There is so much fascinating work in this field. Interesting how stress can impact memory as well as decision making…good incentives for keeping it to a minimum. Small doses can, as you noted, give us that performance edge but running on high levels for long periods of time comes with a lot of costs.
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It’s that fine line between just enough and too much, Tambre…
Roy, I seem to remember that this work is the same as the basis behind NLP? Is there a connection?
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NLP is not science- this is. That makes things very different, Roberta.
That’s like saying Robert Spritzer’s “gay conversion” was real psychiatry- which, now that he is about to go black (won’t be able to speak or act) due to his succumbing to Parkinson’s has just admitted was BS…
Agreed not science and you are a scientific man. But how much of medicine, science and invention have looked at things because someone somewhere postulated, theorized, surmised or supposed. Yes science proves something real or not but often the concept existing because of observation of other things long before science studies it.
Roberta Budvietas, recently posted..Contests build fans!
Quite an interesting study; what remains to be known is how successful the application is to fields of medical development. But then again, low level of stress is so much easier said than done…
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Oh, Hajra, just because folks like you and I thrive on stress:-) does not mean that there aren’t others who manage to minimize stress factors.
Roy
Very interesting post Roy. It shows how important it is to protect your brain from possible damage. Losing a good memory would be terrible. Also, I found the information that you provided about how high and chronic levels of stress impair memory. A little stress can be motivational but high stress has many negative physical and mental health consequences. Hopefully, effective stress management can counteract the effect of chronic stress on memory… Very interesting post!
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Kristen-
You said it every well. Thanks for helping the discussion!
Roy
Well first off Roy, I don’t think I would have want to be those test patients! But this is yet another interesting read and wouldn’t know, stress is always a factor of messing things up! So I just need to relax with a glass of wine, have my husband rub my feet and let those memory cells come forth.
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Sound like a wonderful plan, Lynn. Especially after a move!
Roy
I welcome the scientific results of this study Roy. It backs up what those of us who have been working with clearing the effects of negative memories for years already know.
What am I about to say is not science either, but I’m going to say it anyway. Emotional Freedom Technique or EFT is able rewire the neural pathways for PTSD and it has been doing this in about 90% of cases for about 20 years or so.
EFT doesn’t wipe the slate clean but it is able to take the negative emotional charge from all memories that cause problems. The benefit of this is shown in the change to behaviour, stress levels, and with problems like addictions, depression and in so many other areas that it is impossible to list them all.
It might not be science, but it has sensational results that are easily duplicateable by average people.
Paradigms in science constantly change, but only after huge shifts in consciousness are made. You are no doubt familiar with Kuhn’s, The Structure of Scientific Revolutions. The scientific community does not have a monopoly on truth although they have managed to convince large portions of the population that they do.
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Actually, Madonna, science does not have a monopoly on truth, but that does not mean that other communities- ones that rely on hearsay and correlation have facts. Just because animals breathe oxygen does not mean if there is no oxygen there can be no life. Mr. Craig has been promoting EFT for PTSD for some time- and, while I am not intimately familiar with those results, the true evaluation of the technique has been such that it has NOT been adopted because of it’s inability to routinely (more than half the time) assure positive results. That does not mean it can’t be perfected to make it work- but it certainly means the other techniques with higher success ratios – and longer term results need to be employed first.
Roy
While reducing stress isn’t easy, you’re right that it can affect so many parts of our lives. It makes sense that when we’re under stress, we can’t think clearly and oftentimes, we make bad decisions. This is an interesting study, BTW, and a good reminder to work at staying calm, relaxed, and less stressed. I always enjoy reading about the test results you learn about.
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Thanks for your comments, Lisa. I’m glad you enjoy the blog.
And, alleviating our stress does, indeed, do wonders for our lives.
Roy
I wonder if this research can be used to help alzheimer’s patients in the future?
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Alessa, given the fact that there are chemicals that block signals as part of Alzheimers, that does not look likely. We first either have to reverse the amyloid formations (assuming they are the cause and not the effect) or find a way to bypass the results of the disease. The disease seems to be a breakdown in communication, not activity.
This post is a great reminder that it is important to pay attention to the stress in our lives. I found your comments about “widow brain” very interesting. I think this might also be a problem for other family members grieving the loss of a loved one.
I noticed a decline in my short term memory after my house flooded during Tropical Storm Allison. It was a very traumatic experience and then the stress continued for a very long time during the period I was getting the house repaired.
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Thanks for amplifying the points in the post, Janette.
I am sure recovering from the trauma of a house flood would be exacerbating- so, yes, stress would be an issue. Now, if you’re lucky, you won’t remember how bad it really was 🙂
Roy
It’s nearly impossible to find experienced people in this particular topic, however, you seem like you know what you’re talking about! Thanks
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