This year’s Nobel prize for medicine has been given to scientists who had discovered the “inner body GPS” in brain cells which locate the positioning system like finding the place where we are and the distance.
The brain stores information in such a way that we can immediately find the way the next time we trace the same path, according to the findings of the research conducted by these Nobel laureates. Their studies proved how the “inner GPS” in the brain makes it possible to orient ourselves in space, demonstrating a cellular basis for higher cognitive function.
John O’Keefe discovered, in 1971, that certain nerve cells in the brain were activated when a rat assumed a particularplace in the environment. Other nerve cells were activated at other places. He proposed that these “place cells” build up an inner map of the environment. Place cells are located in a part of the brain called the hippocampus.
More than three decades later, in 2005, May-Britt och Edvard I. Moser discovered in 2005 that other nerve cells in
a nearby part of the brain, the entorhinal cortex, were activated when the rat passed certain locations. Together, these locations formed a hexagonal grid, each “grid cell” reacting in a unique spatial pattern. Collectively, these grid cells form a coordinate system that allows for spatial navigation.
The discoveries of John O´Keefe, May-Britt Moser and Edvard Moser have solved a problem that has occupied philosophers and scientists for centuries – how does the brain create a map of the space surrounding us and how can we navigate our way through a complex environment?
The sense of place and the ability to navigate are fundamental to man’s existence. More than 200 years ago, the German philosopher Immanuel Kant argued that some mental abilities exist as a priori knowledge, independent of experience. He considered the concept of space as an inbuilt principle of the mind, one through which the world is and must be perceived.
With the advent of behavioural psychology in the mid-20th century, these questions could be addressed experimentally. When Edward Tolman examined rats moving through labyrinths, he found that they could learn how to navigate, and proposed that a “cognitive map” formed in the brain allowed them to find their way.
But how would such a map be represented in the brain? While John O´Keefe found the brain map location, May-Britt and Edvard Moser found the coordinates.
May-Britt and Moser were mapping the connections to the hippocampus in rats moving in a room when they discovered an astonishing pattern of activity in a nearby part of the brain called the entorhinal cortex. Here, certain cells were activated when the rat passed multiple locations arranged in a hexagonal grid.
Each of these cells was activated in a unique spatial pattern and collectively these “grid cells” constitute a coordinate system that allows for spatial navigation. Together with other cells of the entorhinal cortex that recognize the direction of the head and the border of the room, they form circuits with the place cells in the hippocampus. This circuitry constitutes a comprehensive positioning system, an inner GPS, in the brain.
Recent investigations with brain imaging techniques, as well as studies of patients undergoing neurosurgery, have provided evidence that place and grid cells exist also in humans. In patients with Alzheimer´s disease, the hippocampus and entorhinal cortex are frequently affected at an early stage, and these individuals often lose their way and cannot recognize the environment.
Knowledge about the brain´s positioning system may, therefore, help us understand the mechanism underpinning the devastating spatial memory loss that affects people with this disease, said the Nobel Foundation while announcing the award for the scientists.
The discovery of the brain’s positioning system represents a paradigm shift in our understanding of how ensembles of specialized cells work together to execute higher cognitive functions. It has opened new avenues for understanding other cognitive processes, such as memory, thinking and planning, the citation from Nobel Foundation said.
John O’Keefe was born in 1939 in New York and holds both American and British citizenships. He received his doctoral degree in physiological psychology from McGill University, Canada in 1967 and moved to England for post-doctoral training at University College London and remained at University College and was appointed Professor of Cognitive Neuroscience in 1987. He is currently Director of the Sainsbury Wellcome Centre in Neural Circuits and Behaviour at University College London.
May-Britt Moser was born in Fosnavåg, Norway in 1963 and is a Norwegian citizen, where the Nobel Foundation has its headquarters. She studied at the University of Oslo together with her future husband and co-Laureate Edvard Moser. She is currently Director of the Centre for Neural Computation in Trondheim.
Her husband Edvard I. Moser was born in born 1962 in Ålesund, Norway and was a postdoctoral fellow together with his wife and co‐Laureate May‐Britt Moser, first at the University of Edinburgh and later a visiting scientist in John O´Keefe´s laboratory in London. In 1996 they moved to the Norwegian University of Science and Technology in Trondheim, where Edvard Moser became Professor in 1998. He is currently Director of the Kavli Institute for Systems Neuroscience in Trondheim.