The 2014 Nobel Prize in Physiology or Medicine has been awarded to three neurologists for their work in helping to understand how the brain can remember where we are – and finding out which nerve cells are responsible.
Half of the prize was awarded to American-born John O'Keefe, who is a naturalized Brit and has spent his career studying at University College London, with the other half being shared between the husband and wife team of May-Britt Moser and her husband Edvard from the Norwegian University of Science and Technology in Trondheim.
"This year's Nobel Laureates have discovered a positioning system, an 'inner GPS' in the brain that makes it possible to orient ourselves in space, demonstrating a cellular basis for higher cognitive function," said the Nobel Prize committee in a statement.
O'Keefe began his work in the late 1960s studying the brain and a decade later discovered the existence of place cells in the dorsal partition of hippocampus. These cells are unique in that they only fire when an animal is in a specific place.
Over the next few decades O'Keefe showed that these place cells form an animal's mental map of its environment – he did most of his work with rat brains – and posited that they could be reapplied to new geographies to help the brain navigate the area.
May-Britt and Edvard Moser worked together as students of O'Keefe and expanded on his work, discovering that the formation of place cells in the hippocampus was generated by activity outside of that section of the brain, in the entorhinal cortex. O'Keefe had postulated the existence of these grids but had never found them.
As animals move through environments the entorhinal cortex creates a hexagonal grid within the brain's tissue. The duo found that these grids act as a compass that activates when the head moves in certain directions.
The work of the three Nobel Prize winners has now been applied to human brains: it has been discovered that we have large hippocampal-entorhinal brain structures, and that these structures have been implicated in spatial learning and episodic memory.
Conditions such as epilepsy, dementia, and Alzheimer’s disease all have an effect on humans' use of this internal GPS system, not just for positioning but in the creation and retention many higher-cognitive brain functions. It's hoped that the application of these theories could help repair damaged brains and extend the useful lives of millions.
"Questions about how we are in the world, how we move in the world, how we process this information, has been a subject for philosophers, psychologists, behaviorists, and experimentalists for centuries," said Professor Juleen Zierath, adjunct member of the Nobel Committee.
"So now we have some evidence of a network in the brain that allows us to understand our space in the world and how we navigate our environment. I think that's a pretty big benefit to mankind – we know much, much more about how we are in the world." ®