Animal's brains are only roughly aware of how high-up they are in space, meaning that in terms of altitude the brain's 'map' of space is surprisingly flat, according to new research.
In a study published online today in Nature Neuroscience, scientists studied cells in or near a part of the brain called the hippocampus, which forms the brain's map of space, to see whether they were activated when rats climbed upwards.
The study, supported by the Wellcome Trust, looked at two types of cells known to be involved in the brain's representation of space: grid cells, which measure distance, and place cells, which indicate location. Scientists found that only place cells were sensitive to the animal moving upwards in altitude, and even then only weakly so.
Professor Kate Jeffery, lead author from UCL Psychology and Language Sciences, said: "The implication is that our internal sense of space is actually rather flat we are very sensitive to where we are in horizontal space but only vaguely aware of how high we are.
"This finding is surprising and it has implications for situations in which people have to move freely in all three dimensions divers, pilots and astronauts for example. It also raises the question if our map of space is flat, then how do we navigate through complex environments so effectively?"
How the hippocampus makes its map of space is fairly well understood for flat environments, but the world is of course not flat it has a richly varied topography, and a useful map therefore needs to work in all three dimensions. However, adding a third dimension to the two horizontal ones makes things very much more complicated for a map, and it is not clear how or even if the brain can encode this.
To begin to answer this question scientists looked at neurons known as grid cells, which become active periodically and at very regular distances as animals walk around, forming a grid-like structure o
|Contact: Clare Ryan|
University College London