Improved spatial memory for physical versus virtual navigation

Spatial memory is a crucial part of our lives. In recent years virtual reality has become a key tool for research into spatial memory. Virtual environments offer many advantages in terms of logistics, combination with neuroimaging and more. However, due to interface limitations in the vast majority of this research participants were stationary. It is well established in animal models that the lack of physical movement in virtual reality impairs some neural representations of space, and this is considered likely to be true in humans as well. However, it is unclear how big this effect actually is -exactly how much does physical movement during encoding and recall affect human spatial memory? Additionally, it is unclear what effect the fatigue of actually walking during the task will have on participants -will it decrease their performance, and possibly increase their perception of difficulty?Here we utilize augmented reality to enable participants to perform a spatial memory task while physically moving in the real world compared to a matched virtual reality task performed in a stationary fashion. Although participants showed good performance in both conditions, they reported that the walking condition was significantly easier, more immersive, and more fun than when stationary. Importantly, memory performance was significantly better in walking compared to stationary. We augment these results in ambulatory human participants with a case study of a patient with an investigational chronic neural implant (Medtronic Summit RC+STM) streaming real-time continuous
hippocampal local field potential data while performing the same spatial memory task. We show evidence for an increase in the amplitude of the neural oscillations associated with movement when moving through the physical world as compared to moving virtually.Our findings validate that integrating AR can lead to improved techniques for spatial memory research and highlight the importance of paradigms that include physical movement to research in this field.