Innovative approach boosts spatial memory using VR and brain stimulation

EPFL researchers have combined virtual reality, non-invasive brain stimulation and advanced brain imaging techniques to improve spatial navigation in healthy participants. The study is a first step in tackling dementia in an aging population without medication or surgery.

As we get older, it becomes harder to remember where things are – whether it’s where we left the keys or where we parked the car. This spatial memory deteriorates further with the onset of dementia, a condition that someone in the world develops every three seconds, according to Alzheimer’s Disease International.

Researchers from two EPFL laboratories have joined forces to boost spatial memory by creating a unique experimental setup that combines non-invasive deep brain stimulation, virtual reality training and fMRI imaging – all housed at Campus Biotech in Geneva. The research, published in Science Advances, shows that targeted, painless electrical impulses to the hippocampus and adjacent structures, a deep brain region involved in memory and spatial navigation, can improve the brain’s ability to remember locations and navigate more effectively.

By finding ways to improve spatial memory without surgery or medication, we are addressing a serious problem for a large and growing population: the elderly, but also brain trauma patients and people with dementia.”

Friedhelm Hummel, head of the Hummel Lab

The study is the result of a collaboration between the Hummel Lab and Olaf Blanke’s Laboratory of Cognitive Neuroscience (LCNO), both at EPFL’s Neuro X Institute. By combining Hummel’s expertise in non-invasive brain stimulation with Blanke’s cognitive research into spatial navigation in virtual reality environments, the researchers developed a unique neurotechnological setup.

A unique combination of neurotechnologies

The experiment begins with researchers placing four harmless electrodes on the heads of healthy individuals to stimulate the hippocampus and adjacent structures. This non-invasive technique, called transcranial temporal interference electrical stimulation (tTIS), sends targeted pulses without causing any discomfort to the participant.

Volunteers are then immersed in a virtual world using VR glasses. Building on previous research by co-first author Hyuk-June Moon, the scientists task participants with navigating a series of locations and remembering key landmarks. This immersive virtual environment allows researchers to accurately measure how well participants can remember and navigate spatial information while receiving tTIS.

“When stimulation was applied, we saw a clear improvement in participants’ recall time – the time it took to start moving in the direction of where they remembered the object to be,” says Elena Beanato, the other first author of the research. “This leads us to believe that by stimulating the hippocampus we have temporarily increased brain plasticity, which, when combined with training in a virtual environment, leads to better spatial navigation.”

The entire experiment was performed in an fMRI scanner. This provided researchers with real-time images of brain activity, allowing them to monitor how the hippocampus and surrounding regions responded to tTIS during the spatial navigation tasks. The fMRI data revealed changes in neural activity associated with the observed behavioral changes, particularly in the regions responsible for memory and navigation, giving the researchers deeper insight into how non-invasive stimulation modulates brain function.

This integration of cutting-edge technologies at EPFL’s Neuro X Institute makes Campus Biotech one of the few places where all three experimental techniques can be combined in one study.

“The alliance of tTIS, virtual reality and fMRI offers a highly controlled and innovative approach to studying the brain’s response to stimulation and its impact on cognitive functions,” adds Olaf Blanke. “In the long term, we want to use this approach to develop targeted therapies for patients suffering from cognitive disorders, providing a non-invasive way to improve memory and spatial skills.”