Alzheimer’s disease may cause early destruction of ‘grid cells’ for navigation
Alzheimer’s disease may cause early destruction of ‘grid cells’ for navigation.
Disorientation is often one of the first warnings of Alzheimer’s disease. Someone gets into the car to go to the grocery store, and suddenly can’t remember how to get there.
Now, neurologists offer a clue as to why the first kind of memory to fade may be navigational.
Grid cells were identified for the first time in 2005, by a group of scientists in Norway interested in how the brain enables animals to navigate. They put six rats in a pen, and monitored individual neurons while the rats explored.
The neurons they were watching lie in a part of the brain called the entorhinal cortex. It sits in the lower part of the brain, near its intersection with the brain stem. This is the perfect position for a mapmaker: the entorhinal cortex gets input about the environment from the senses, and sends its output up to the hippocampus, which is known for its roles in memory and navigation.