Grid cells’ role in human imagination revealed

Evidence of grid cell activity has been seen in healthy volunteers asked to imagine moving through an environment in new UCL research funded by the Medical Research Council and the Wellcome Trust. The study, published in Current Biology, used fMRI scans to detect brain activity consistent with grid cell activity in the entorhinal cortex, an important 'hub' for navigation and memory. The entorhinal cortex is one of the first areas affected by Alzheimer's disease, so the latest research could help to explain why people with Alzheimer's can have problems imagining as well as remembering things. Grid cells are brain cells that act as an internal coordinate system, firing at a series of locations that form a hexagonal grid across our environment as we move around it. The latest research provides the first evidence that these cells are also used when we imagine navigating, not only for tracking past or present environments. "People with Alzheimer's disease can find it difficult to visualise and remember scenes, and our new findings may help to explain why," says senior author Professor Neil Burgess, Director of the UCL Institute of Cognitive Neuroscience. "We previously developed a test called the Four Mountains Test, where participants have to hold in mind a mountainous landscape and then try to identify it from a line-up of four landscapes, one of which is the original shown at a different point of view.