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November 2001
- The cell's cytoskeleton contains protein structures called "microtubules".
We used to think that neurons had no inner structure, but now more and more
attention is being paid to its internal structure and in particular to its
cytoskeleton. The microtubules of the cytoskeleton could give rise quantum
processes and account for free will, and this has started a whole school of
thought about quantum consciousness.
(Lots of information on the cytoskeleton at:
Nature.com).
Kazuhisa Kinoshita at the
Max Planck Institute in Dresden is one of the
researchers who are studying the behavior of microtubules.
He has published a paper in which he describes the "dynamic instability" of
these structures (they self-destroy rapidly) and shows how he has produced
microtubules in vitro that are instead "well-behaved", a step towards
understanding them better.
- Bose-Einstein condensates are exotic materials in which all atoms become one,
they become indistinguishable. Some theories of consciousness (see my book,
chapter on Consciousness)
are interested in Bose-Einstein condensates because consciousness behaves like a
Bose-Einstein condensate and one only has to prove that Bose-Einstein
condensates are possible in the brain to make the connection.
Unfortunately, so far Bose-Einstein condensates have been produced only for
elements that hardly qualify as "thinking" stuff (rubidium, sodium, hydrogen,
helium, lithium). Giovanni Modugno at the
University of Firenze
has successfully produced a Bose-Einstein condensate out of a mixture of
rubidium and potassium atoms. This has added potassium to the list of
condensable elements and, most important, the technique they employed promises
to further expand this restricted family, thereby making Bose-Einstein
condensates more common than we previously thought.
- There has been growing debate about the regeneration of neurons
since it was first announced that our brain is capable of creating new neurons
not only during development but also in adult age. This would mean that our
brain is not just slowly "dying" but continuously being regenerated.
David Kornack at the University of Rochester and Pasko Rakic of Yale Univ
now report that they have found no evidence of new neurons in the neocortex
of adult primates (the neocortex being where most of our "intelligence"
resides). The only cells that are created are supporting cells that have
little to do with "thinking". This is somewhat in contrast with previous
experiments that showed growth of new neurons at least in the
hippocampus.
June 2001
- Researchers at the Institute for Neuroscience in Baltimore report that a
protein called "agrin" has been found to regulate
the immunological synapse. This synapse is not the kind of synapse found
in the brain:
it represents the border between the organism and the antigen that has
infected it.
The immune system works thanks to two cellular systems, both of which
involve cells called "lymphocytes".
One kind of lymphocytes produce a circulating (i.e., mediated by body
fluids) immune system derived from B-cells ("B" because they are derived
from bone marrow cells). The other kind of lympohocytes produce a
cellular (i.e., mediated by cells) immune system derived from T-cells
("T" because they are derived from the thymus). B-cell immunity includes
the circulating antibodies, whereas T-cells act as coordinators and
effectors of the immune system.
The findings show that it is agrin that determines if and when a "T
cell" signals.
Agrin is so called because it is an "aggregating" protein:it induces the
aggregation of signaling proteins, i.e. it helps in the "construction"
of nervous pathways (or, better, "signaling domains").
It is released from the terminals of motor neurons and it is well known
to be involved in the development of the nervous system. (Incidentally,
it is also abnormality associated with Alzheimer's disease).
This finding confirms that agrin is responsible for the creation of
signaling domains in both immune and
nervous system; and it sheds light on how it "regulates" immune-system
cells. Given the similarities between immune and nervous system, it is
likely that this research will also shed light on how the brain is built
and regulated.
- www.humanbrainmapping.org
is the website of the Organization for Human Brain Mapping (OHBM) a
Boston-based organization dedicated to neuroimaging research and in
particular to creating a neuroimaging database. Both the name and the
mission mirror the Human Genome Project. Unfortunately, the neuroimaging
community has not done a good job of sharing data.
Therefore there isn't yet a global repository of brain images.
- If we needed any further evidence that our mind shows us only what it
wants to show us, Yoram Bonneh, of the Smith-Kettlewell Eye Research
Institute in San Francisco, has documented how tthe brain erases some
aspects of the visual field.He prepared a computer screen with a
swirling pattern of blue dots superimposed on some stationary yellow
dots. To most observers, the yellow dots appear to come and go. But in
reality the erasing happens in the mind, not the computer (see the story
in Nature
Magazine). Of course, one cannot rule out that similar "discarding"
or even altering of reality do not occur more often, during our daily
life. Bonneh's explanation of this "motion-induced blindness" is that
our mind has a theory of the world and sensory inputs must conform with
that theory or are discarded. The illusion may well be the result of a
fight for supremacy between the circuitry of the brain that makes sense
of the world as a whole and the circuitry of the brain that deals with
sensory input, the former suppressing sensory input that conflicts with
its theory the world.
- Andrew Cohen, Nima Arkani-Hamed and Howard Georgi have presented a
theory on how the universe came to be a four-dimensional one. According
to their theory, the universe may have started with just a single
dimension: time. As the universe cooled down after the big bang, space
was born with its three dimensions. Far from being eternal, space would
merely be the stage on which particles interact: there is no space
without particles. Particles came first, space was a consequence. A
fundamental theory of spacetime must therefore start with particles, and
then deduce space. This would represent a complete reversal of our
cosmology, as dramatic as the one due to Copernicus centuries ago.
In the beginning , after all, there was only a point. Whatever the
universe was before the big bang, it did not have a spatial dimension:
it was one dimension-less dot. The "big-bang" explosion caused a cooling
of the temperature, and with the cooling things started (literally)
materializing: particles, atoms, molecules, etc. These are moving
objects, and they move in three dimensions. In a sense, each dimension
corresponds to a level of energetic excitation. A little energy is
enough to move in one direction, but only back and forth: the world has
one dimension. A little more energy is needed to start moving sideways
as well. Even more energy is necessary to move up and down while moving
back and forth and sideways. A new dimension arises when the universe's
energy allows movement of a new kind.
Needless to say, the question is now: why three? Why not two or four?
One reply could be that maybe we are still transitioning and that
eventually a fourth spatial dimension will be born and then another and
then another. (As a reminder, superstring theory presumes ten
dimensions).
Another question is: why were dimensions born in later stages of the
universe if they require some energy and energy was maximum at the very
beginning, in the infinite density and temperature of the
(dimension-less) big bang? That requires some technical discussion on
that "energy". But the bottom line is that we know some particles (the
gluons that glue together quarks in protons) are very weak at high
energies and very strong at lower energies.They "embody" energy that
can do amazing things, but they will do them only at low energies. It
would not be surprising if the same turned out to be true of all
dimension-creating particles.
Interestingly enough, this theory is relatively simple to test. If it is
true, then elementary particles such as quarks and gluons should move in
fewer dimensions when the conditions of the early universe are
replicated inside colliders. Raise the temperatures and those particles
should start moving only back and forth on a straight line. If we could
raise the temperature to the level it was during the big bang (don't try
this at home), particles should stop moving completely.
May 2001
- Kevin Warwick is professor of Cybernetics at the Reading University (UK).
In 1998 he made the headlines by inserting a microchip in his arm and
connecting it to the environment (his house). This way Warwick added a
new type of interaction between his body and the environment.
In September, Warwick plans to connect such a microchip with his nervous system
to gather information about the sensations and the feelings associated
with our mental life.
First and foremost, Warwick wants to "store" information about our internal
life. This will provide invaluable knowledge and possibly allow to
neutralize some emotions (eg, pain).
Note that Warwick is both the subject and the object of his experiments.
The closer you get to consciousness, the less you can use external objects.
Rats are great to figure out how conditioning works, but not ideal for
figuring out how it feels to be human.
Later, the same chip will be implanted in his wife. Once the two chips
are connected, telepathy will become reality, as each of the two will be able
to "feel" the emotions of the other.
Cyberpunks will love the idea that same day we will exchange emotions just like
today we exchange emails.
February 2001
- Despite the hype of the joint announcement about the completion of the human
genome project, almost nothing has been completed. While the media have
widely reported that the number of genes in humans is 30,000, this is only a
hasty estimate by the parties who wanted to make the announcement as soon as
possible. The estimate by Human Genome Sciences (http://www.hgsi.com/) still
stands at 100,000.
The fact that Human Genome Sciences is proceeding much slower than Celera
does not mean that Celera did a better job.
Celera candidly admits that most of the DNA appears to be "junk". That's
another thing that the human genome project was supposed to explain. It is
obviously not junk. It just takes time to figure out what it is.
January 2001
- Researchers have found strong evidence that dreaming is not a human exclusive and that dreaming helps consolidate memories.
MIT researchers led by Matthew Wilson
detected patterns of brain activity in sleeping rats that match
their patterns of brain activity during day activity.
The laboratory rats appear to be dreaming of the maze they were learning to
navigate.
The patterns of brain activity that were observed when the rats ran a circular
maze were exactly duplicated while the rats were sleeping.
The neural patterns are the firing of clusters of cells in the hippocampus,
one of the main areas for memory formation and storage.
The duplication was extremely faithful. One could pinpoint the place in
the maze were the rat was dreaming of being.
This finding is important to support theories such as Allan Hobson's and
Jonathan Winson's, according to which the day's memories are "rehearsed" in
the hippocampus during sleep and moved to long-term memory.
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In 1984 the Australian geologist Simon Wilde extracted a
4.4 billion year old crystal from an ancient rock. That crystal, according
to the American geologist John Valley, is now
yielding information about the Earth's past. It may signal that
oceans already existed. The birth of life is assumed to coincide
with the birth of water, take or leave a few million years.
So far, it was believed that we living beings are 3.85 billion years old
(happy birthday :-), because oceans were presumed to be 3.85 billion years
old, but this finding would push back that date by half a billion years.
Biologists and chemists have long debated how life could have developed
so "quickly" from the "primordial soup", since the chances
of the right elements occurring at the right time in the right place
at the right temperature are very low. But an extra half a billion
years would greatly increase the chances that chemistry worked out some
magic by itself.
-
Neuroscientists and zoologists have failed to identify brain structures that
are specialized for musical tasks (several structures seem to be implicated,
and those structures are shared with other tasks such as language and
reasoning), but their studies are showing that our brains are naturally
adapted to music, and we share this property with most if not all vertebrates.
This lends credibility to the thesis that music is a very ancient mechanism.
First, music was one of the earliest cognitive functions performed by humans:
musical instruments have been found (in France and Sweden) that are at least
50,000 years old. Thus, we were playing music way before we
learned to paint, sculpt or write.
Second, an analysis of sounds produced by birds and whales has shown that
animals employ the same system of musical composition (rhythm, notes,
harmony) that humans employ. While each animal has different anatomical
structures that enable it to produce different kinds of sounds (especially
whales, who boast a seven-octave range), all birds
and mammals study so far tend to use the same "aesthetics". Animals tend to
"sing in key" and to "rhyme".
Their songs tend to employ the structure of commercial pop
music (intro, refrain, bridge, refrain). That, of course,
explains why we humans enjoy listening to birds singing.
Animals employ counterpoint and "call and response" in a natural way.
A bird's song is immediately picked up by another bird that joins in
the jamming.
Since those species have wildly different evolutionary ages, this phenomenon
suggests that musical cognition arose very early in the development of
vertebrates, way before humans were born.
Prominent among cognitive-musical research are the works of the Canadian
neurologist
Isabelle Peretz
(who has studied the neural circuits where musical perception occurs,
as documented in "Le cerveau musical").
and the
American composer Patricia Gray, whose
recent article covers the universality of music.
More information can be found at the
Music Cognition page at Ohio State.
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