Washington: Scientists have located what they claim is an "inner compas" at the back of the human brain that informs people about the direction they are heading, a key
finding that may pave the way for tests to detect dementia.
An international team, led by Queensland University, has discovered that a person`s ability to find their way is learned gradually and that the brain eventually becomes tuned
to key landmarks in the new environment.
Dr Oliver Baumann, who led the team, had volunteers learn to navigate to landmarks around a computer-generated maze over several days. He then measured the volunteers` brain activity as they viewed each of the landmarks in isolation.
"The brain acts like a compass, with different neurons firing depending on the direction people think they are heading," Dr Baumann said.
In the research, published in the latest edition of the `Journal of Neuroscience`, the scientists used functional magnetic resonance imaging to monitor people`s brain activity
as they carried out the computerised testing.
They found that a small area in the parietal cortex, located toward the back of brain, provides critical information about the direction in which a person is heading.
"Here we have evidence in a normal, healthy human population that there is a dedicated cluster of neurons that encodes our sense of direction.
"If this brain region is damaged it can severely disrupt a person`s ability to navigate in new situations. Such damage is common in stroke and Alzheimer`s disease. People
haven`t made this link before -- previously it`s a clinical anecdote," team member Jason Mattingley said.
Mattingley predicted clinicians could eventually use navigational tests as an early probe for the onset dementia. "Our research suggests that one of the important cognitive
functions we should be testing in people with suspected dementia is their sense of direction," he said.
There might even be scope to test the controversial claim that men`s sense of direction really is better than women`s. "Our approach could provide an objective test by revealing whether male and female brains respond differently during navigation tasks," Prof Mattingley said.