Brain's sense of direction located
Specialized neurons in the brain "fire" corresponding to the direction a person is moving, Australian researchers have found.
Researchers have long known that some animals determine direction by using magnetic fields that influence parts of their brain.
This new study, published Thursday in The Journal of Neuroscience, is the first time scientists have identified parts of the human brain that map approximately to direction.
The researchers, led by Dr. Oliver Baumann of the Queensland Brain Institute, also found the more familiar someone is with an environment, the better they are at navigating.
The study, which involved 13 male and female participants, used a randomly generated computer maze featuring prominent landmarks that subjects learned to navigate their way around. The subjects were then shown the landmarks in isolation.
In both tests, the subjects' brains were measured using functional magnetic resonance imaging (fMRI), which shows changes in the brain as they happen.
The researchers found a small area in the parietal cortex, located towards the back of the brain, lit up when the subjects were navigating the maze. It also lit up when the participants were shown the maze landmarks in isolation.
"There are a lot of nodes in the brain being used for navigation," says Baumann. "We just looked at the way that people navigate in a single plane which would correspond to what we think of as north, south, east and west."
The project is part of a longer four-year study examining how people, as well as robots and animals, navigate through their environments.
The study also throws light on the way the brain functions in people with brain damage, such as Alzheimer's disease.
Anecdotally, it has long been suspected that people with Alzheimer's lose their ability to navigate. Now that the area of the brain that corresponds to navigation is known, clinicians may be able to develop tests that catch the disease in its early stages through simple navigation tests.
But what's not yet clear is why some people are far better at navigating than others.
"We will take this research further in this direction," says Baumann, "and look at things like visual variability to determine why some people are better navigators than others."
Prof. Jason Mattingley, one of the co-authors, says the research could also be used to settle the age old debate regarding women and direction.
"It is often suggested that females are poorer at navigation than males, but scientific evidence for this is controversial," says Mattingley. "Our approach could provide an objective test by revealing whether male and female brains respond differently during navigation tasks."