Navigating our thoughts: Fundamental principles of thinking -- ScienceDailyThe very regular activation pattern of grid cells can also be observed in humans -- but importantly, not only during navigation through geographical spaces. Grids cells are also active when learning new concepts, as shown by a study from 2016. In that study, volunteers learned to associate pictures of birds, which only varied in the length of their necks and legs, with different symbols, such as a tree or a bell. A bird with a long neck and short legs was associated with the tree whereas a bird with a short neck and long legs belonged to the bell. Thus, a specific combination of bodily features came to be represented by a symbol. In a subsequent memory test, performed in a brain scanner, volunteers indicated whether various birds were associated with one of the symbols. Interestingly, the entorhinal cortex was activated, in much the same way as it is during navigation, providing a coordinate system for our thoughts. "By connecting all these previous discoveries, we came to the assumption that the brain stores a mental map, regardless of whether we are thinking about a real space or the space between dimensions of our thoughts. Our train of thought can be considered a path though the spaces of our thoughts, along different mental dimensions," Jacob Bellmund, the first author of the publication, explains.