Dementia: New insights into causes of loss of orientation

‘New research has revealed how disease-associated changes in 2 interlinked networks within the brain may play a key role in the development of the symptoms of dementia’ – via ScienceDaily

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The University of Exeter Medical School led two studies, each of which moves us a step closer to understanding the onset of dementia, and potentially to paving the way for future therapies. Both studies, part-funded by Alzheimer’s Research UK, are published in the Journal of Neuroscience and involved collaboration with the University of Bristol.

Both studies shed light on how two parts of the brain’s ‘GPS’ navigation system malfunctions in dementia, and point to likely underpinning causes for loss of orientation that is commonly experienced by people living with the condition.

In the first study, the team studied a part of the brain called the entorhinal cortex. Located near the base of the brain, this region is associated with functions including memory formation and navigation, and contains so-called “grid cells.” These nerve cells fire electrical discharges in a grid-like pattern, much like the grid on an Ordnance Survey map. Paralleling the different scales employed by different maps, the grid firing patterns in the entorhinal cortex also have different scales, with cells at the top of the cortex having a more tightly packed grid pattern than those at the bottom. Scientists believe that this top-to-bottom gradient of different grid scales contributes pivotally to our sense of spatial location.

The team compared the activity in the entorhinal cortex of healthy mice and mice with dementia. They found that top-to-bottom gradients in electrical activity in the entorhinal cortex are not present in mice with dementia. Their findings suggest that the fine navigational detail, such as you would find on a large-scale map, is not correctly represented in patients with dementia.

Carry on reading via ScienceDaily

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