Remember when Will Smith and Tommy Lee Jones used a neurolyzer to erase people’s memories with blue light in » Men in Black» ? Well, we can’t do that yet, but some scientists have done something remarkably similar. On October 9, UC Davis announced that researchers there «erased specific memories» in mice using light.

The secret of the technology lies in a fascinating field called optogenetics, and it has already begun to change the way we think about the brain.

What is optogenetics?

By scientific standards, optogenetics is a very recent field, having only been around since 2002. If you’re familiar with scientific naming conventions, you’ve probably figured out that optogenetics combines light (opto) and genetics, but how it works is amazing (and very cool). First, a quick neuroanatomy lesson.

The brain is made up of trillions of neurons, each of which is connected to many other neurons, the same structure is reflected in artificial neural networks and neuromorphic chips. When a neuron fires or «fires», it communicates with other neurons and creates a cascade of neural activity — this is what causes thoughts and actions (for more information on how the brain works, check out the HowStuffWorks explanation).

So where is the light? Usually nothing. However, with a little genetic modification, scientists have been able to breed mice whose brains contain neurons that respond to light, meaning that when a certain set of neurons are exposed to a very specific wavelength of blue light, they can be turned on or off.

This has been used in small animals such as nematodes and roundworms to induce muscle action, and has even been used to make a mouse run with a switch (link leads to video of the experiment; it’s pretty cool, but I decided not to embed if you don’t want to so that animal testing is done in action — it’s not so bad).

However, when it comes to the brain, things like motor activation and neural circuit mapping are not as complex as changing memory. Scientists have been studying memory and cognition for a long time, and there is still disagreement about how it works and what the relationship is between a neuron or group of neurons and specific cognitive functions.


there will be a blacksmith-neuralyzer

A recent study from the University of California, Davis has made a big breakthrough in optogenetics and memory. To really understand what was going on in this study, I’m going to take you through an experiment.

Long before the experiment, mice had been genetically modified so that their neurons could be exposed to blue light. A tiny light was implanted into the mouse’s brain to provide the necessary optical stimulation, and then the experiment began. In this particular experiment, mice were placed in a cage that shocked them. Once they learn the connection between cage and shock, they will immediately freeze when placed in that cage; this is called the fear response.

After the mice learned this response, the researchers turned on a blue light that targeted certain neural clusters. The mice, when re-introduced into the shock cage, no longer showed fear responses—they «forgot» what they were afraid of.

blue LEDs

Of course, to say that the researchers erased the memory of the mice is a bit of an oversimplification; it was a very simple conditioned memory and response, and it was suppressed by the application of blue light.

With that said, this is definitely a step forward in how we understand the brain (if you’re interested in the neuroanatomy of the experiment, it showed that the hippocampus and the cortex are involved in memory retrieval at the same time, and that the cortex can’t do it alone. It also showed, that certain parts of the hippocampus are activated during memory retrieval).

Future Considerations

While you don’t have to worry about someone crashing into your brain with blue light and erasing your memories anytime soon, it raises some very serious questions about the future of optogenetic research. No studies have been done with humans yet, but recent studies have used primates, so it’s likely that humans are on track. Due to the genetic component, it can be quite a while before this happens (if you want to see for yourself, you might consider putting your brain on ice). and check back in a few decades).

It’s not hard to imagine someone trying to figure out how to find a wavelength of light that would work without the genetic component. Whether this is possible or not is of course beyond the scope of this article, but it makes for an interesting thought experiment. If scientists figure out how to manipulate neurons without prior genetic manipulation, we might someday see the world straight from puppet at home (and if you haven’t seen Dollhouse I recommend it).

What do you think of this study? Think we could head for the pocket neurolyzers? Share your thoughts below!

Image credit: LED background with dozens of transparent blue LEDs.

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