In the human brain, the hippocampus is responsible for the processing of our experiences into longterm memories. Diseases and injuries effecting this part of the brain result in the loss of our ability to form long term memories.
Location of the hippocampus within the human brain.
To explain, when the human brain receives sensory input (sight, smell, sound, etc.), it encodes a memory as an electrical signal which travels through multiple regions of the hippocampus. The signal is re-encoded in each region and is stored for the long term at the end of its journey.
The prosthesis developed at USC is comprised of an array of electrodes implanted in the brain. Having been tested on animals and more recently on humans, the device has been proven to accurately mimic how a memory is encoded.
With these results, the implant may be used to replace the damaged region of the hippocampus to encode a memories.
In human testing, individuals suffering from chronic seizures received the implant to help researchers see how accurately it could predict how their memories would be encoded.
Researchers from Wake Forest Baptist read the electrical signals created during memory formation at two regions of the subject’s hippocampi. This information was sent to a team at USC, who constructed a research model able to read how the signals generated in the first region of the hippocampus are translated by the second.
In over one hundred trials conducted with nine patients, the algorithm used by the implant predicted how the signals would be translated with about 90 percent accuracy.
“Being able to predict neural signals with the USC model suggests that it can be used to design a device to support or replace the function of a damaged part of the brain,” said Robert Hampson of the Department of Physiology & Pharmacology of Wake Forest Baptist.
In further experiments, the two teams hope to use the implant in a subject with a damaged region in their hippocampus.
Alzheimer’s and Brain Injury
The implant may be used to treat patients suffering from memory loss due to Alzheimer’s disease, but experts believe the technology is not yet advanced enough.
“A prosthetic memory device is a very exciting prospect, but it has taken decades of research to get this far and there are still many unknowns that need to be worked out by the scientists,” said Dr. Clare Walton of the Alzheimer’s Society. “If this device is developed further and successfully tested in humans, it could prove to be an effective treatment for some of the symptoms of dementia. However, it will not cure or slow down the progression of the condition.”
Surprisingly, or maybe not, the project was funded by DARPA, with the intent to help injured soldiers overcome memory loss.
But let’s stop and put on our tinfoil hats for a moment.
What we're talking about is a brain implant that can influence the development of human memory. Is mind control technology or at least mind reading technology, the next step for USC’s implant?
According to Theodore Berger, professor of biomedical engineering and a key member of the project, there is no way to read a memory just by looking at its electrical signal. “It’s like being able to translate from Spanish to French without being able to understand either language,” Berger said.
And so, we remove our tinfoil hats.
Maybe the technology could lead to the “Internet of People,” where implants connect us all to something like the Cloud and we share each other’s thoughts? Something fun to speculate.
Berger worked with research associate Dong Song, who developed the implant’s algorithm and is also part of the USC Viterbi School of Engineering.
The research by USC and Wake Forest Baptist was presented at the 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society in Milan on Aug. 27, 2015.