The brain's GPS has a buddy system -- ScienceDailyIt has been known for some time that the hippocampus maintains a mental map of space -- in fact, the 2014 Nobel Prize in Physiology or Medicine was awarded precisely for this research. 'Place cells' and 'grid cells' in the hippocampus register the location of the brain's owner in its environment, but until now, little was known about how the movements of others are tracked in the brain. Researchers put this to the test by observing the activity of hippocampal neurons in one rat (the 'self') watching another rat (the 'other') go through a simple T-maze. The self's neurons registered what the other was doing and changed their responses based on the self's location and subsequent actions. This study was published on January 11 in Science, which also contains a report of similar location awareness in the brains of bats.