Neural prosthesis can help humans restore memory

A team of scientists from Wake Forest University School of Medicine and the University of Southern California (USC) have demonstrated the first successful use of a neural prosthesis to recall specific memories.

The results appear in Frontiers of Computational Neuroscience.

This groundbreaking research comes from the 2018 study by the Wake Forest and USC team led by Robert Hampson, Ph.D., professor of regenerative medicine, translational neuroscience, and neurology at the University of Michigan Medical School. Wake Forest University, which demonstrated the successful implementation of a prosthetic system. which uses a person’s own memory patterns to facilitate the brain’s ability to encode and recall memory.

In the previous study, the team’s electronic prosthetic system was based on a nonlinear multi-input, multi-output (MIMO) mathematical model, and the researchers influenced the firing patterns of several hippocampal neurons, a part of the brain involved in the production of new neurons. memories.

In this study, researchers built a new model of the process that helps the hippocampus memorize specific information. When the brain tries to store or recall information such as “I turned off the stove” or “Where did I put my car keys?” groups of cells work together in neuronal ensembles that activate so that information is stored or recalled.

Using recordings of the activity of these brain cells, the researchers created a memory decoding model (MDM), which allows them to decode which neuronal activity is used to store different specific pieces of information. The neural activity decoded by the MDM was then used to create a template, or code, used to apply neurostimulation to the hippocampus when the brain was trying to store this information.

“Here, we not only highlight an innovative neurostimulation technique to improve memory, but we also demonstrate that memory stimulation is not limited to a general approach but can also be applied to specific information essential to a person “Brent said. Roeder, Ph.D., a researcher in the Department of Translational Neuroscience at Wake Forest University School of Medicine and corresponding author of the study.

The team recruited 14 adults with epilepsy who were participating in a brain-mapping diagnostic procedure using surgically implanted electrodes placed in various parts of the brain to identify the origin of their seizures.

Participants underwent all surgical procedures, postoperative monitoring, and neurocognitive testing at one of three sites participating in this study, including Atrium Health Wake Forest Baptist Medical Center, Keck Hospital of USC in Los Angeles, and the Rancho Los Amigo National Rehabilitation Center in Downey, California.

The team administered MDM electrical stimulation during visual recognition memory tasks to see if the stimulation could help people remember images better. They found that when they used this electrical stimulation, significant changes occurred in the way people remembered things. In about 22% of cases, there was a noticeable difference in performance.

When they looked specifically at participants with memory disorders, who received stimulation on both sides of their brain, almost 40% of them showed significant changes in memory performance.

“Our goal is to create an intervention that can restore memory function lost due to Alzheimer’s disease, stroke or head trauma,” Roeder said. “We found that the most pronounced change occurred in people with memory problems.”

Roeder said he hopes the technology can be perfected to help people live independently by helping them remember critical information such as whether medications have been taken or whether a door is locked.

“Although more research is needed, we know that MDM-based stimulation has the potential to be used to significantly modify memory,” Roeder said.

Preclinical work applied the same type of stimulation to restore and facilitate memory in animal models using the MIMO system, developed at USC.