Book Introduction - Leelavathi 108 Problems of Dr. S Balachandra Rao
Vijayavani Vidyarthi Mitra 27 Oct 2014
Tuesday, October 28, 2014
Book Introduction - Leelavathi 108 Problems of Dr. S Balachandra Rao - Vijayavani Vidyarthi Mitra 27 Oct 2014
Book Introduction - Leelavathi 108 Problems of Dr. S Balachandra Rao
Vijayavani Vidyarthi Mitra 27 Oct 2014
Monday, October 27, 2014
Homeopathy for Animals - A Novel Application - Vijayavani Vittavani 27 Oct 2014
http://epapervijayavani.in/epaperimages/27102014/27102014-md-hr-17/3448916.JPG
Wednesday, October 22, 2014
IAS Prelims 2014 Results Announced - Article in Vijay Karnataka - VK Jobs 22 Oct 2014
IAS Prelims 2014 Results Announced - Article in Vijay Karnataka - VK Jobs 22 Oct 2014
http://vijaykarnatakaepaper.com/epaperimages/22102014/22102014-md-hr-34/2614416.JPG
Tuesday, October 21, 2014
Cambodian Folk Tale - Tum Teav - Thushara Monthly Nov 2014
Cambodian Folk Tale - Tum Teav - Thushara Monthly Nov 2014
Samasyapoorna and Kannada Literature - Kasturi Monthly Nov 2014
Samasyapoorna and Kannada Literature - Kasturi Monthly Nov 2014
Friday, October 17, 2014
UPSC Civil Services (Prelims) 2014 Results Announced - Vijaya Next Career VK Weekly - 23 Oct 2014
http://vijayanextepaper.com/epaperimages/17102014/17102014-md-hr-22/185824171.JPG
Thursday, October 16, 2014
e-Learning - A Golden Opportunity of Joy Learning by Bedre Manjunath Published by Navakarnataka Publications
http://issuu.com/bedremanjunath/docs/e-learning_-_a_golden_opportunity_o?e=1178968/9752033
e-Learning - A Golden Opportunity of Joy Learning by Bedre Manjunath
Published by Navakarnataka Publications
PP: 64+4 Price: Rs.20/- Ph. 080-22203580
e-Learning - A Golden Opportunity of Joy Learning by Bedre Manjunath
Published by Navakarnataka Publications
PP: 64+4 Price: Rs.20/- Ph. 080-22203580
Monday, October 13, 2014
The Nobel Prize for Economics 2014
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2014
Jean Tirole
Jean Tirole
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2014
Photo: Mme Tirole (IDEI). CC-BY-SA-3.0 via Wikimedia Commons
Jean Tirole
Prize share: 1/1
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2014 was awarded to Jean Tirole "for his analysis of market power and regulation".
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2014
Jean Tirole
Jean Tirole
 |
|
Press Release
13 October 2014The Royal Swedish Academy of Sciences has decided to award The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel for 2014 to
Jean Tirole
Toulouse 1 Capitole University, France
“for his analysis of market power and regulation”.
The science of taming powerful firms
Jean Tirole is one of the most
influential economists of our time. He has made important theoretical
research contributions in a number of areas, but most of all he has
clarified how to understand and regulate industries with a few powerful
firms.
Many industries are dominated by a small number of large firms or a
single monopoly. Left unregulated, such markets often produce socially
undesirable results – prices higher than those motivated by costs, or
unproductive firms that survive by blocking the entry of new and more
productive ones.From the mid-1980s and onwards, Jean Tirole has breathed new life into research on such market failures. His analysis of firms with market power provides a unified theory with a strong bearing on central policy questions: how should the government deal with mergers or cartels, and how should it regulate monopolies?
Before Tirole, researchers and policymakers sought general principles for all industries. They advocated simple policy rules, such as capping prices for monopolists and prohibiting cooperation between competitors, while permitting cooperation between firms with different positions in the value chain. Tirole showed theoretically that such rules may work well in certain conditions, but do more harm than good in others. Price caps can provide dominant firms with strong motives to reduce costs – a good thing for society – but may also permit excessive profits – a bad thing for society. Cooperation on price setting within a market is usually harmful, but cooperation regarding patent pools can benefit everyone. The merger of a firm and its supplier may encourage innovation, but may also distort competition.
The best regulation or competition policy should therefore be carefully adapted to every industry’s specific conditions. In a series of articles and books, Jean Tirole has presented a general framework for designing such policies and applied it to a number of industries, ranging from telecommunications to banking. Drawing on these new insights, governments can better encourage powerful firms to become more productive and, at the same time, prevent them from harming competitors and customers.
| Read more about this year's prize |
| Information for the Public Pdf 229 kb |
| Scientific Background Pdf 606 kb |
To read the text you need Acrobat Reader.
|
Images:
Illustration (pdf 583 kB)
Jean Tirole, French citizen. Born 1953 in Troyes, France. Ph.D. 1981 from Massachusetts Institute of Technology, Cambridge, MA, USA. Scientific Director at Institut d’Économie Industrielle, Toulouse School of Economics, Toulouse 1 Capitole University, France.
www.idei.fr/vitae.php?i=3
The Prize amount: SEK 8 million.
Contacts: Jessica Balksjö Nannini, Press Officer, +46 8 673 95 44, +46 70 673 96 50, jessica.balksjo@kva.se
Tore Ellingsen, Chairman of The Committee for the Prize in Economic Sciences in Memory of Alfred Nobel, +46 8 736 92 60, tore.ellingsen@hhs.se
This year marks the 275th anniversary of The Royal
Swedish Academy of Sciences. The Academy was founded in 1739 and is an
independent organization whose overall objective is to promote the
sciences and strengthen their influence in society. The Academy takes
special responsibility for the natural sciences and mathematics, but
endeavours to promote the exchange of ideas between various disciplines.
Friday, October 10, 2014
Shikshana Varthe Monthly October 2014 - Book Introduction of the Biography of Dr Sukumara Gowda written by K R Vidyadhar
Shikshana Varthe Monthly October 2014 - Book Introduction of the Biography of Dr Sukumara Gowda written by K R Vidyadhar
Published by Kanthavara Kannada Sangha, Udupi Dist
Price Rs.33/- Ph 8970185166
http://www.schooleducation.kar.nic.in/shikshanavarthe/SV1014.pdf
http://www.schooleducation.kar.nic.in/html/shikshanavarthe.html
Published by Kanthavara Kannada Sangha, Udupi Dist
Price Rs.33/- Ph 8970185166
http://www.schooleducation.kar.nic.in/shikshanavarthe/SV1014.pdf
http://www.schooleducation.kar.nic.in/html/shikshanavarthe.html
The Nobel Peace Prize 2014
The Nobel Peace Prize 2014
Kailash Satyarthi, Malala Yousafzay
Kailash Satyarthi, Malala Yousafzay
The Nobel Peace Prize 2014
Kailash Satyarthi
Born: 11 January 1954, Vidisha, India
Residence at the time of the award: India
Prize motivation: "for their struggle against the suppression of children and young people and for the right of all children to education"
Prize share: 1/2
Born: 11 January 1954, Vidisha, India
Residence at the time of the award: India
Prize motivation: "for their struggle against the suppression of children and young people and for the right of all children to education"
Prize share: 1/2
Malala Yousafzay
Born: 12 July 1997, Mingora, Pakistan
Residence at the time of the award: United Kingdom
Prize motivation: "for their struggle against the suppression of children and young people and for the right of all children to education"
Prize share: 1/2
The Nobel Peace Prize 2014 was awarded jointly to Kailash Satyarthi and Malala Yousafzay "for their struggle against the suppression of children and young people and for the right of all children to education"
| English |
| Norwegian |
The Nobel Peace Prize for 2014
The Norwegian Nobel Committee has decided that the Nobel Peace Prize for 2014 is to be awarded to Kailash Satyarthi and Malala Yousafzay for their struggle against the suppression of children and young people and for the right of all children to education. Children must go to school and not be financially exploited. In the poor countries of the world, 60% of the present population is under 25 years of age. It is a prerequisite for peaceful global development that the rights of children and young people be respected. In conflict-ridden areas in particular, the violation of children leads to the continuation of violence from generation to generation.Showing great personal courage, Kailash Satyarthi, maintaining Gandhi’s tradition, has headed various forms of protests and demonstrations, all peaceful, focusing on the grave exploitation of children for financial gain. He has also contributed to the development of important international conventions on children’s rights.
Despite her youth, Malala Yousafzay has already fought for several years for the right of girls to education, and has shown by example that children and young people, too, can contribute to improving their own situations. This she has done under the most dangerous circumstances. Through her heroic struggle she has become a leading spokesperson for girls’ rights to education.
The Nobel Committee regards it as an important point for a Hindu and a Muslim, an Indian and a Pakistani, to join in a common struggle for education and against extremism. Many other individuals and institutions in the international community have also contributed. It has been calculated that there are 168 million child labourers around the world today. In 2000 the figure was 78 million higher. The world has come closer to the goal of eliminating child labour.
The struggle against suppression and for the rights of children and adolescents contributes to the realization of the “fraternity between nations” that Alfred Nobel mentions in his will as one of the criteria for the Nobel Peace Prize.
Oslo, 10 October 2014
Books for Translation - Vijaya Next 16 Oct 2014
http://vijayanextepaper.com/epaperimages/10102014/10102014-md-hr-22/213362.JPG
Thursday, October 9, 2014
The Nobel Prize in Literature 2014
The Nobel Prize in Literature 2014 was awarded to Patrick Modiano
"for the art of memory with which he has evoked the most ungraspable
human destinies and
uncovered the life-world of the occupation".
The Nobel Prize in Literature 2014
Patrick Modiano
Patrick Modiano
|
The Permanent Secretary Press Release
9 October 2014
The Nobel Prize in Literature 2014
Patrick Modiano
The Nobel Prize in Literature for 2014 is awarded to the French author Patrick Modiano
“for the art of memory with which he has evoked the most ungraspable human destinies and uncovered the life-world of the occupation”.
Wednesday, October 8, 2014
The Nobel Prize in Chemistry 2014
Eric Betzig
Prize share: 1/3
Stefan W. Hell
Prize share: 1/3
The Nobel Prize in Chemistry 2014 was awarded jointly to Eric Betzig, Stefan W. Hell and William E. Moerner "for the development of super-resolved fluorescence microscopy".
The Nobel Prize in Chemistry 2014
Eric Betzig, Stefan Hell, William Moerner
 |
|
Press Release
8 October 2014
The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2014 to
Eric Betzig
Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA,
Stefan W. Hell
Max Planck Institute for Biophysical Chemistry, Göttingen, and German Cancer Research Center, Heidelberg, Germany
and
William E. Moerner
Stanford University, Stanford, CA, USA
“for the development of super-resolved fluorescence microscopy”
Surpassing the limitations of the light microscope
For a long time optical microscopy was held back by a
presumed limitation: that it would never obtain a better resolution
than half the wavelength of light. Helped by fluorescent molecules the
Nobel Laureates in Chemistry 2014 ingeniously circumvented this
limitation. Their ground-breaking work has brought optical microscopy
into the nanodimension.
In what has become known as nanoscopy,
scientists visualize the pathways of individual molecules inside living
cells. They can see how molecules create synapses between nerve cells in
the brain; they can track proteins involved in Parkinson’s, Alzheimer’s
and Huntington’s diseases as they aggregate; they follow individual
proteins in fertilized eggs as these divide into embryos.
It was all but obvious that scientists should ever be able to study
living cells in the tiniest molecular detail. In 1873, the microscopist
Ernst Abbe stipulated a physical limit for the maximum resolution of
traditional optical microscopy: it could never become better than 0.2
micrometres. Eric Betzig, Stefan W. Hell and William E. Moerner
are awarded the Nobel Prize in Chemistry 2014 for having bypassed this
limit. Due to their achievements the optical microscope can now peer
into the nanoworld.
Two separate principles are rewarded. One enables the method stimulated emission depletion (STED) microscopy,
developed by Stefan Hell in 2000. Two laser beams are utilized; one
stimulates fluorescent molecules to glow, another cancels out all
fluorescence except for that in a nanometre-sized volume. Scanning over
the sample, nanometre for nanometre, yields an image with a resolution
better than Abbe’s stipulated limit.
Eric Betzig and William Moerner, working separately, laid the foundation for the second method, single-molecule microscopy.
The method relies upon the possibility to turn the fluorescence of
individual molecules on and off. Scientists image the same area multiple
times, letting just a few interspersed molecules glow each time.
Superimposing these images yields a dense super-image resolved at the
nanolevel. In 2006 Eric Betzig utilized this method for the first time.
Today, nanoscopy is used world-wide and new knowledge of greatest benefit to mankind is produced on a daily basis.
| Read more about this year's prize |
| Popular Information Pdf 1.4 MB |
| Scientific Background Pdf 979 Kb |
To read the text you need Acrobat Reader.
|
Eric Betzig, U.S. citizen. Born 1960 in Ann Arbor,
MI, USA. Ph.D. 1988 from Cornell University, Ithaca, NY, USA. Group
Leader at Janelia Farm Research Campus, Howard Hughes Medical Institute,
Ashburn, VA, USA.
Stefan W. Hell, German citizen. Born 1962 in
Arad, Romania. Ph.D. 1990 from the University of Heidelberg, Germany.
Director at the Max Planck Institute for Biophysical Chemistry,
Göttingen, and Division head at the German Cancer Research Center,
Heidelberg, Germany.
William E. Moerner, U.S. citizen. Born 1953 in
Pleasanton, CA, USA. Ph.D. 1982 from Cornell University, Ithaca, NY,
USA. Harry S. Mosher Professor in Chemistry and Professor, by courtesy,
of Applied Physics at Stanford University, Stanford, CA, USA.
The Prize amount: SEK 8 million, to be shared equally between the Laureates.
Contact persons: Jessica Balksjö Nannini, Press Officer, Phone +46 8 673 95 44, +46 70 673 96 50, jessica.balksjo@kva.se
Måns Ehrenberg, member of the Nobel Committee for Chemistry, +46 70 433 23 81, ehrenberg@xray.bmc.uu.se
This year marks the 275th anniversary of The Royal
Swedish Academy of Sciences. The Academy was founded in 1739 and is an
independent organization whose overall objective is to promote the
sciences and strengthen their influence in society. The Academy takes
special responsibility for the natural sciences and mathematics, but
endeavours to promote the exchange of ideas between various disciplines.
Guru Puraskara - Foreign and All India Tour for Teachers - Vijayavani Masth 08 Oct 2014
Guru Puraskara - Foreign and All India Tour for Teachers - Vijayavani Masth 08 Oct 2014
http://epapervijayavani.in/epaperimages/8102014/8102014-md-hr-20/41121641.JPG
Lap Top Lab Everywhere - Vijayavani 08 Oct 2014
http://epapervijayavani.in/epaperimages/8102014/8102014-md-hr-20/4959416.JPG
Tuesday, October 7, 2014
The Nobel Prize in Physics 2014
The Nobel Prize in Physics 2014
Isamu Akasaki, Hiroshi Amano, Shuji Nakamura
The Nobel Prize in Physics 2014 was awarded jointly to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources".
The Nobel Prize in Physics 2014
Isamu Akasaki, Hiroshi Amano, Shuji Nakamura
Isamu Akasaki, Hiroshi Amano, Shuji Nakamura
 |
|
Press Release
7 October 2014
The
Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2014 to
Isamu Akasaki
Meijo University, Nagoya, Japan and Nagoya University, Japan
Hiroshi Amano
Nagoya University, Japan
and
Shuji Nakamura
University of California, Santa Barbara, CA, USA
“for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources”
New light to illuminate the world
This year’s Nobel Laureates are rewarded for having
invented a new energy-efficient and environment-friendly light source –
the blue light-emitting diode (LED). In the spirit of Alfred Nobel the
Prize rewards an invention of greatest benefit to mankind; using blue
LEDs, white light can be created in a new way. With the advent of LED
lamps we now have more long-lasting and more efficient alternatives to
older light sources.
When Isamu Akasaki, Hiroshi Amano and Shuji Nakamura
produced bright blue light beams from their semi-conductors in the
early 1990s, they triggered a funda-mental transformation of lighting
technology. Red and green diodes had been around for a long time but
without blue light, white lamps could not be created. Despite
considerable efforts, both in the scientific community and in industry,
the blue LED had remained a challenge for three decades.
They succeeded where everyone else had failed. Akasaki worked
together with Amano at the University of Nagoya, while Nakamura was
employed at Nichia Chemicals, a small company in Tokushima. Their
inventions were revolutionary. Incandescent light bulbs lit the 20th
century; the 21st century will be lit by LED lamps.
White LED lamps emit a bright white light, are long-lasting and
energy-efficient. They are constantly improved, getting more efficient
with higher luminous flux (measured in lumen) per unit electrical input
power (measured in watt). The most recent record is just over 300 lm/W,
which can be compared to 16 for regular light bulbs and close to 70 for
fluorescent lamps. As about one fourth of world electricity consumption
is used for lighting purposes, the LEDs contribute to saving the Earth’s
resources. Materials consumption is also diminished as LEDs last up to
100,000 hours, compared to 1,000 for incandescent bulbs and 10,000 hours
for fluorescent lights.
The LED lamp holds great promise for increasing the quality of life
for over 1.5 billion people around the world who lack access to
electricity grids: due to low power requirements it can be powered by
cheap local solar power.
The invention of the blue LED is just twenty years old, but it has
already contributed to create white light in an entirely new manner to
the benefit of us all.
| Read more about this year's prize |
| Information for the Public Pdf 1.1 MB |
| Scientific Background Pdf 770 kB |
To read the text you need Acrobat Reader.
|
Isamu Akasaki,, Japanese citizen. Born 1929 in
Chiran, Japan. Ph.D. 1964 from Nagoya University, Japan. Professor at
Meijo University, Nagoya, and Distinguished Professor at Nagoya
University, Japan.
Hiroshi Amano,, Japanese citizen. Born 1960 in
Hamamatsu, Japan. Ph.D. 1989 from Nagoya University, Japan. Professor at
Nagoya University, Japan.
Shuji Nakamura, American citizen. Born 1954 in
Ikata, Japan. Ph.D. 1994 from University of Tokushima, Japan. Professor
at University of California, Santa Barbara, CA, USA.
Prize amount: SEK 8 million, to be shared equally between the Laureates.
Contact persons: Jessica Balksjö Nannini, Press Officer, Phone +46 8 673 95 44, +46 70 673 96 50, jessica.balksjo@kva.se
Olle Inganäs, member of the Nobel Committee for Physics, +46 13 28 12 31, ois@ifm.liu.se
Nobel Prize® är is a registered trademark of the Nobel Foundation.
This year marks the 275th anniversary of The Royal
Swedish Academy of Sciences. The Academy was founded in 1739 and is an
independent organization whose overall objective is to promote the
sciences and strengthen their influence in society. The Academy takes
special responsibility for the natural sciences and mathematics, but
endeavours to promote the exchange of ideas between various disciplines.
Book Introduction - Kalam Nimagido Salam of GKM - Vijayavani Vidrathi Mithra 07 Oct 2014
Book Introduction - Kalam Nimagido Salam of GKM - Vijayavani Vidrathi Mithra 07 Oct 2014
The Nobel Prize in Physiology or Medicine 2014
The Nobel Prize in Physiology or Medicine 2014
John O'Keefe, May-Britt Moser, Edvard Moser
John O'Keefe, May-Britt Moser, Edvard Moser
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".
John O'Keefe - Facts
Photo: David Bishop, UCL
John O'Keefe
Born: 1939, New York, NY, USA
Affiliation at the time of the award: University College, London, United Kingdom
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/2
Born: 1939, New York, NY, USA
Affiliation at the time of the award: University College, London, United Kingdom
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/2
May-Britt Moser - Facts
Photo: Kavli Institute, NTNU, CC-BY-SA-3.0 via Wikimedia Commons
May-Britt Moser
Born: 1963, Fosnavåg, Norway
Affiliation at the time of the award: Centre for Neural Computation, Trondheim, Norway
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/4
Photo: Kavli Institute, NTNU, CC-BY-SA-3.0 via Wikimedia Commons
Press Release
Born: 1963, Fosnavåg, Norway
Affiliation at the time of the award: Centre for Neural Computation, Trondheim, Norway
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/4
Edvard Moser - Facts
Photo: Kavli Institute, NTNU, CC-BY-SA-3.0 via Wikimedia Commons
Edvard I. Moser
Born: 1962, Ålesund, Norway
Affiliation at the time of the award: Kavli Institute for Systems Neuroscience, Trondheim, Norway
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/4
Born: 1962, Ålesund, Norway
Affiliation at the time of the award: Kavli Institute for Systems Neuroscience, Trondheim, Norway
Prize motivation: "for their discoveries of cells that constitute a positioning system in the brain"
Field: physiology, spatial behavior
Prize share: 1/4
2014-10-06
The Nobel Assembly at Karolinska Institutet has today decided
to award
The 2014 Nobel Prize in Physiology or Medicine
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.
Monday, October 6, 2014
Book Introduction - Shikshana Siddhanti Dr N Sukumara Gowda by K R Vidyadhara - Vijayavani Vidyarthi Mitra 29 Sept 2014
Book Introduction - Shikshana Siddhanti Dr N Sukumara Gowda by K R Vidyadhara - Vijayavani Vidyarthi Mitra 29 Sept 2014
Book Introducton - Kannada Kayagala Gejjenaada Vol 1 and 2 of Hanyalu Prakashana - Vijayavani Vidyarthi Mitra 16 Sept 2014
Book Introducton - Kannada Kayagala Gejjenaada Vol 1 and 2 of Hanyalu Prakashana - Vijayavani Vidyarthi Mitra 16 Sept 2014
Subscribe to:
Posts (Atom)