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London: Scientists have now decoded how nerve cells
in the brain work in establishing one's location and direction,
which may be crucial to one's survival.
Neurobiologist Jeffrey Taube, professor of psychological and brain
sciences at Dartmouth College, is using micro-electrodes to record
the activity of cells in a rat's brain that make possible spatial
navigation.
Such navigation involves how the organism gets from one place to
another -- from "here" to "there". But before embarking to go
"there", you must first define "here".
"Knowing what direction you are facing, where you are, and how to
navigate are really fundamental to your survival," Taube was
quoted in the journal Nature Neuroscience.
"For any animal that is preyed upon, you'd better know where your
hole in the ground is and how you are going to get there quickly.
And you also need to know direction and location to find food
resources, water resources, and the like."
"It only comes to your attention when something goes wrong, like
when you look for your car at the end of the day and you can't
find it in the parking lot," said Taube, according to a Dartmouth
statement.
Perhaps this is a momentary lapse, a minor navigational error, but
it might also be the result of brain damage due to trauma or a
stroke, or it might even be attributable to the onset of a disease
such as Alzheimer's.
One critical component involved in this process is the set of
neurons called "head direction cells".
They act like a compass based on the direction your head is
facing. They are located in the thalamus, a structure that sits on
top of the brainstem, near the centre of the brain.
Taube is also studying neurons he calls "place cells". These cells
work to establish your location relative to some landmarks or cues
in the environment.
The place cells are found in the hippocampus, part of the brain's
temporal lobe. They are based not on the direction you are facing,
but on where you are located.
"What we are trying to argue in this paper is that they are really
two different, separate brain processes, and we demonstrated it
empirically," Taube added.
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