A memory boosting brain implant

Today’s increasingly advanced technology has helped humans surpass their bodies normal limitations. Now scientists are testing an implant that could help improve memory–especially for those who suffer from cognitive disorders. Michael Kahana, Director of the University of Pennsylvania computational Memory Lab joins Hari Sreenivasan to discuss how memory works and how is it stored on our brains.


Today's increasingly advanced technology has helped humans surpass their body's normal limitations.

Now, scientists are testing an implant that could help improve memory, especially for those who suffer from cognitive disorders.

Joining us now to discuss is Michael Kahana, director of the University of Pennsylvania Computational Memory Lab.

So, before we get into this implant, how does memory work?

How is it stored in our brains?

That's a great and really complex question.

One thing that we've learned recently is that storing memories depends on a widespread network of activity across multiple brain regions.

It's not any single individual part of the brain that stores the memory, and the process of storing memories is highly variable.

Sometimes the same person will succeed or fail for reasons that we don't fully understand, and that very ability is a key part of the puzzle.

There seem to be tricks and tips that we can use to try to record a memory, but when we're not actively trying to memorize something, how's the brain making decisions on what's important and what's not important?

Well, I think that some things that are really important, we know they're important, and our brain will respond to that with dopamine, and that will help to effectively store memories.

Is there... Let's talk a little bit about the implant.

What is the implant, and what did it do?

Well, we've been working with patients who have severe epilepsy.

These are patients who are undergoing neurosurgical treatment to address their seizure disorder, and surgeons will implant hundreds of electrodes inside of the brain in many regions to try and map the focus of the seizures -- where the seizures are originating in the brain -- so that those regions can then be safely resected, sparing the healthy tissue of the brain and hopefully sending a patient home with far fewer seizures or even no seizures.

And so in our hands, the research that we've been doing involves studying these patients' memories while we electrically stimulate the brain with very safe and weak pulses of electricity.

But the implant is not yet an implant in the sense that it is an external stimulator that is controlling the impulses for the electrodes that are implanted in these patients' brains for clinical purposes.

But a future implant could be a fully encapsulated device, a device that is entirely sealed within the body and that would responsively stimulate the human brain based on the activity that it detects, which would then tell it where, when, and how stimulation ought to be delivered.

What did you learn from your study so far?

What was working, or what worked, or what was the result?

Right, so the key finding that we had was that when we stimulate the lateral temporal cortex, which is this part of the brain right behind my left temple, we were able to significantly enhance memory function but only when we stimulated the brain at moments when the electrical network activity of the brain signaled that failure was going to happen.

In other words, it signaled that memories were not going to be effectively formed, and when we stimulate just then, we show that we're actually able to produce a 15% average enhancement in memory function, but in many cases, the enhancement's effect was far larger than that.

You're working with a population who have trouble storing memory, but could you see this being used with someone who has no problems to try to improve their capacity to store and recall memory?

I think it's theoretically possible.

I mean, the main issue is surgical risk and mitigating the surgical risk, but you could imagine that you could use it to make memory better, though obviously you would have a greater chance of making memory better if memory wasn't already functioning well most of the time.

So what's the potential for a product like this to be commercially viable in the future given how large a population suffers from Alzheimer's and dementia and other disorders?

Well, so what we've shown is a proof of concept, and there's still a lot of work that would have to be done to translate this into a viable technology that could be implanted in large numbers of people.

I think that work is possible.

It's not really pushing the envelope too far in the sense that it's all within the set of things that people have been able to do in the last several years, but it's putting a lot of technical advances together in some interesting new ways.

So other than, you know, an implant or a memory enhancement like this, what are more simple things that people can do to be conscious of how to improve their memory or how to maintain and retain and then also retrieve memories?

Well, you know, since the time of the ancient Greeks, if not earlier, we've known a lot about mnemonics that help people remember things, but those mnemonics are training.

They're hard to use.

They require a lot of practice and a lot of intention, and, you know, certainly many of them are ones that are familiar to all of us.

It's helpful if you elaborate information.

If you work hard in storing the information, the more you process it, the better it will be stored, and another recent discovery is that it's very important to test your memory in order to support subsequent retention of new information that you've learned.

Another well-known finding in the memory literature is the spacing effect.

If you space out training, you'll remember things better.

...anybody can do.

If you're studying for an exam, you can use these techniques effectively, but they don't work automatically, and there are people for whom the automatic are so severely hampered that they can't perform just basic acts of daily living.

All right. Michael Kahana, professor of psychology at the University of Pennsylvania, thanks so much for joining us.

My pleasure. Thank you.