The
Nobel Prize in Physiology or Medicine 2014
Photo: David Bishop,
UCL
John O'Keefe
Prize share: 1/2
|
Photo: Kavli
Institute, NTNU,
CC-BY-SA-3.0 via Wikimedia Commons
May-Britt Moser
Prize share: 1/4
|
Photo: Kavli
Institute, NTNU, CC-BY-SA-3.0 via Wikimedia Commons
Edvard I. Moser
Prize share: 1/4
|
The Nobel Prize in
Physiology or Medicine 2014 was divided, one half awarded to John O'Keefe, the
other half jointly to May-Britt Moser and Edvard I. Moser "for
their discoveries of cells that constitute a positioning system in the
brain".
Reference:
"The Nobel Prize in Physiology or
Medicine 2014". Nobelprize.org. Nobel Media AB 2014. Web. 6 Oct 2014. http://www.nobelprize.org/nobel_prizes/medicine/laureates/2014/
Here is the Press Release by The Nobel Assembly at Karolinska Institutet on 2014-10-06
The Nobel Assembly at
Karolinska Institutet has today
decided to award
The 2014 Nobel Prize in
Physiology or Medicine
with one half to
John O´Keefe
and the other half jointly to
May-Britt Moser and Edvard I. Moser
for their discoveries of cells that constitute a positioning
system in the brain
system in the brain
How do we know where we are? How can we find the way from one
place to another? And how can we store this information in such a way that we
can immediately find the way the next time we trace the same path? 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.
In 1971, John O´Keefe discovered the first component of this
positioning system. He found that a type of nerve cell in an area of the brain
called the hippocampus that was always activated when a rat was at a certain
place in a room. Other nerve cells were activated when the rat was at other
places. O´Keefe concluded that these “place cells” formed a map of the room.
More than three decades later, in 2005, May-Britt and Edvard Moser
discovered another key component of the brain’s positioning system. They
identified another type of nerve cell, which they called “grid cells”, that
generate a coordinate system and allow for precise positioning and pathfinding.
Their subsequent research showed how place and grid cells make it possible to
determine position and to navigate.
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?
How do we experience our environment?
The sense of place and the ability to navigate are fundamental to
our existence. The sense of place gives a perception of position in the
environment. During navigation, it is interlinked with a sense of distance that
is based on motion and knowledge of previous positions.
Questions about place and navigation have engaged philosophers and
scientists for a long time. 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 questions still lingered - how would such a map be represented in the
brain?
John O´Keefe and the place in space
John O´Keefe was fascinated by the problem of how the brain
controls behaviour and decided, in the late 1960s, to attack this question with
neurophysiological methods. When recording signals from individual nerve cells
in a part of the brain called the hippocampus, in rats moving freely in a room,
O’Keefe discovered that certain nerve cells were activated when the animal
assumed a particular place in the environment (Figure 1). He could demonstrate
that these “place cells” were not merely registering visual input, but were
building up an inner map of the environment. O’Keefe concluded that the
hippocampus generates numerous maps, represented by the collective activity of
place cells that are activated in different environments. Therefore, the memory
of an environment can be stored as a specific combination of place cell
activities in the hippocampus.
May-Britt and Edvard Moser find the coordinates
May-Britt and Edvard 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 (Figure 2). 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 (Figure 3).
A place for maps in the human 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.
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.
Key publications:
|
O'Keefe,
J., and Dostrovsky, J. (1971). The hippocampus as a spatial map. Preliminary
evidence from unit activity in the freely‐moving
rat. Brain Research 34, 171-175.
|
O´Keefe,
J. (1976). Place units in the hippocampus of the freely moving rat.
Experimental Neurology 51, 78-109.
|
Fyhn,
M., Molden, S., Witter, M.P., Moser, E.I., Moser, M.B. (2004) Spatial
representation in the entorhinal cortex. Science 305, 1258-1264.
|
Hafting,
T., Fyhn, M., Molden, S., Moser, M.B., and Moser, E.I. (2005). Microstructure
of spatial map in the entorhinal cortex. Nature 436, 801-806.
|
Sargolini,
F., Fyhn, M., Hafting, T., McNaughton, B.L., Witter, M.P., Moser, M.B., and
Moser, E.I. (2006). Conjunctive representation of position, direction, and
velocity in the entorhinal cortex. Science 312, 758-762.
|
John O’Keefe was born in 1939 in New York City, USA, and holds both American
and British citizenships. He received his doctoral degree in physiological
psychology from McGill University, Canada in 1967. After that, he moved to
England for postdoctoral training at University College London. He has remained
at University College and was appointed Professor of Cognitive Neuroscience in
1987. John O´Keefe 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. She studied psychology
at the University of Oslo together with her future husband and co-Laureate
Edvard Moser. She received her Ph.D. in neurophysiology in 1995. She was a postdoctoral
fellow at the University of Edinburgh and subsequently a visiting scientist at
University College London before moving to the Norwegian University of Science
and Technology in Trondheim in 1996. May-Britt Moser was appointed Professor of
Neuroscience in 2000 and is currently Director of the Centre for Neural
Computation in Trondheim.
Edvard I. Moser was born in born 1962 in Ålesund, Norway and
has Norwegian citizenship. He obtained his Ph.D. in neurophysiology from the
University of Oslo in 1995. He 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.
(Reference: "The 2014 Nobel Prize in Physiology or Medicine - Press Release".Nobelprize.org. Nobel Media AB 2014. Web. 7 Oct 2014. <http://www.nobelprize.org/nobel_prizes/medicine/laureates/2014/press.html>)
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