How brain senses location, direction decodedPublished On: Sun, Oct 21st, 2012 | Neurobiology | By IANS
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”.
“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.
Valerio S, Taube JS. Path integration: how the head direction signal maintains and corrects spatial orientation. Nature Neuroscience. 2012 Oct;15(10):1445-53. doi: 10.1038/nn.3215. Epub 2012 Sep 16.