WHY THIS MATTERS IN BRIEF

This breakthrough converted human memories into digital binary code, then downloaded and re-uploaded them in living human subjects with great results.

Just months after two different teams of researchers figured out hot to edit and delete human memories Researchers in the US have figured out how to “strengthen the storage of new memories in the human brain” using electrical stimulation and neural patterns that were previously used to store other human memories. Or to say it in another way scientists, for the first time, have managed to create a new type of augmented brain prosthetic that boosts human memory retention and recall by over a third in particular patients. And it could be the start of something revolutionary, especially when you consider that increasingly scientists are developing new ways, for example using the Neural Lace and other Brain to Machine interfaces, to connect human brains directly to computers and Artificial Intelligence (AI), and stream movies from our heads – and more.

The report, published in the Journal of Neural Engineering, is the first to crack the neural codes linked to specific, individual memories in the human hippocampus, says Robert Hampson, a professor at Wake Forest Baptist Medical Center, who co-authored it. And the research is one of several approaches that could one day lead to “brain prostheses” to fill in for lost memory.

As complicated as manipulating a specific memory sounds, there’s also a simplicity to it. After all, neurons in the brain communicate via electrical impulses. The brain’s communication system can be hacked by feeding in artificially generated electrical messages, like tapping in Morse code.

In the new report, the researchers accomplished that on a highly targeted level. They focused on episodic memory – information that is new and useful for a short period of time, like where you parked your car, or where you put your keys.

“Episodic memory is very sensitive,” says Hampson. “It’s easily damaged.”

The study went like this. Forteen volunteers, with electrodes implanted in their brains, performed a memory task similar to that involved in episodic memory. As they did this, the researchers recorded, in the brain’s hippocampus, the patterns of electrical activity associated with the storage of the memory. It’s worth noting here that all the participants had already had electrodes implanted in their brains for a separate epilepsy procedure, and they didn’t get “chipped” just for the purposes of this experiment.

“We were able to get simultaneous recordings from anywhere from 10 to 60 neurons at a time,” says Hampson. Amazingly, even when a person’s memory is impaired, it is possible to identify the neural firing patterns that indicate correct memory formation, he says.

Then, using a multi-input, multi-output (MIMO) nonlinear mathematical model developed by bioengineers Theodore Berger and Dong Song at the University of Southern California in Los Angeles, they then decoded those neural patterns into digital binary 1’s and 0’s and synthesised a digital code for correct memory storage. Berger’s team has previously used the model to decode animal memories.

With this so called digital “neural code” in hand, the team could then recreate the memories it represented artificially using their volunteers brain prostheses. Volunteers were then asked to perform a memory task, and as they did, the researchers fed electrical impulses, in a precise pattern customized for each volunteer, to the target area of the hippocampus, influencing the firing pattern of those neural circuits.

In other words they recorded the brain activity associated with the storage of specific information, mathematically modelled and decoded that activity, and then wrote the code back into brain to make existing memory work better.

With the electrical boost, volunteers’ memory performance improved by 35 percent, according to the report. The improvement was even higher in patients who had experienced greater memory loss. Among the volunteers with good memory, there wasn’t much change, Hampson says.

Key to the success was the microelectrodes, which were designed to record the activity of single neurons. That, in combination with Berger’s mathematical model, which had been honed for coding memory patterns, enabled the project, Hampson says.

The study was funded by DARPA, the US Department of Defense’s research arm, through its Restoring Active Memory, or RAM program. Through this program, the agency has been challenging neuroscientists to develop an implantable device that can mitigate memory loss in vets with traumatic brain injury.

Elsewhere another RAM awardee, Michael Kahana at the University of Pennsylvania, reported another advance in memory prostheses – his group identified brain states that signal when memory is predicted to fail, and designed stimulation that would promote the brain state associated with success. His group previously found that electrical stimulation should be delivered precisely when memory is predicted to fail, rather than when memory is operating efficiently.

All in all this research is just the tip of the ice berg of a new field of research where scientists develop artificial brain prosthetics that can both boost and augment human memory.