Brain's 'internal compass' found

By Smitha Mundasad
Health reporter, BBC News

image sourceThinkstock

The precise part of the brain that gives people a sense of direction has been pinpointed by scientists.

People with stronger nerve signals in their "internal compass" tended to be better navigators.

The study, published in the journal Current Biology, suggested people get lost when their compass cannot keep up.

The researchers in London hope the discovery will help explain why direction sense can deteriorate in conditions such as Alzheimer's disease.

Scientists have long believed that such a signal existed within the brain, but until now it had been pure speculation.

Researchers at University College London (UCL) asked 16 volunteers to familiarise themselves with a simple virtual courtyard.

image sourceUCL
image captionVolunteers were asked to navigate towards certain objects placed in four corners of the virtual room

They were then asked to navigate the area, from memory alone, while their brains were being scanned by an MRI machine.

The scans revealed a part of the brain - known as the entorhinal region - fired up consistently during the tasks.

The stronger the signal in the region, the better the volunteers were at finding their way around correctly.

Dr Hugo Spiers, who led the study, said: "Studies on London cab drivers have shown that the first thing they do when they work out a route is calculate which direction they need to head in.

"We now know the entorhinal cortex is responsible for such calculations and the quality of the signals from this region seem to determine how good someone's navigational skills will be."

Dr Martin Chadwick, who was also involved in the study, explained: "Our results provide evidence to support the idea that your internal compass readjusts as you move through the environment.

"For example if you turn left, then your entorhinal region should process this to shift your facing direction and goal direction accordingly.

"If you get lost after taking too many turns, this may be because your brain could not keep up and failed to adjust."

Degenerative diseases

Previous work by UCL researchers uncovered the role the entorhinal region plays in helping people understand what direction they are facing.

This new work suggests the area also helps them decide which direction to move in when heading to a new location.

Dr John Isaac, from the Wellcome Trust, which funded the study, said: "Why some people are better navigators than others is intrinsically interesting, but it also helps us explain the processes that go wrong in degenerative diseases such as dementia - leaving people feeling lost and confused."

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