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Scientists turn up startling diversity among nerve cells
Peer out the window of a plane landing at LaGuardia Airport, and the tiny people scurrying around the streets of New York City all look the same. But take a stroll down Fifth Avenue and a new view emerges: Up close, New Yorkers are very different.
A street view of the brain also reveals a new perspective: No two cells are the same. Zoom in, and the brain’s wrinkly, pinkish-gray exterior becomes a motley collection of billions of cells, each with personalized quirks and idiosyncrasies.
Powerful new techniques are giving researchers a glimpse of this staggering diversity — especially among nerve cells, the brain’s information brokers. Even nerve cells presumed to do the same job come in a range of shapes and sizes and display a host of behaviors, sending their electrical messages in unpredictable ways, new studies reveal. The closer scientists scrutinize nerve cells, called neurons, the more differences turn up.
This cellular menagerie has left researchers puzzling over how best to categorize what neuroscientist Rafael Yuste of Columbia University calls these “living creatures.” So far, systematic methods are lacking. “Even after 100 years of research, we have no clue how many classes of neurons there are,” says Yuste, a Howard Hughes Medical Institute researcher. He and other scientists are developing new algorithms to automate neuron classification, in the hope of someday compiling a standard “parts list” of the brain.
While some scientists are hard at work categorizing all these different cells, others are thinking about what such diversity means for living, breathing animals. New results suggest, for instance, that a population of nerve cells in which individual responses to an electrical poke differ can process more information than a group in which responses are the same. Others think that variety might help the brain cope with a changing environment.
Accounting for all of the individual brain components — a task as daunting as finding out every New Yorker’s favorite color, credit score and whether they cry at sad movies — isn’t just a tedious sorting job. A deeper knowledge of the brain’s inhabitants might lead to new treatments for brain-related disorders. If particular cells are more vulnerable to diseases such as dementia, schizophrenia and autism, therapies that protect or target these cell populations may be effective. More broadly, knowing who is doing what in the brain will help scientists understand the inner workings of the impossibly complex three-pound hunk of flesh that sits in the skull.
Interesting article:
Residents of the brain: Scientists turn up startling diversity among
nerve cells
http://www.sciencenews.org/view/feature/id/332400/title/Residents_of_…“No two cells are the same. Zoom in, and the brain’s wrinkly, pinkish-
gray exterior becomes a motley collection of billions of cells, each
with personalized quirks and idiosyncrasies.”“New results suggest, for instance, that a population of nerve cells
in which individual responses to an electrical poke differ can process
more information than a group in which responses are the same. ““in addition to losing neurons, the brain would lose diversity, a
deficit that could usher in even more damage.”I would say this tends to support my view that the idea of replacement
neurons or normative behavior modeling is likely to be a dead end as
far as functionalism is concerned. It’s more appropriate to consider
your brain a civilization of individual organisms (only some of which
are the conscious ‘I’) rather than a powerful computer executing
complicated instructions.
The perfect lie detector may be closer to reality than you think. The opportunities for its misuse are many, but MRI and EEG-based lie detection science is on the brink of being able to detect lies with startling accuracy - sometimes before you even know you’re going to lie.
Where there are people, there are lies. The theory of Machiavellian intelligence claims that our capacity to deceive was developed by virtue of our distant ancestors’ way of life and refined as their primate brains grew and developed more complex structures. Our closest relatives indicate that, from an evolutionary point of view, it has to do with the youngest part of the brain, that outer layer of coiling tissue called the neocortex, which takes up nearly eighty percent of human brain volume. The Scottish primatologist Richard Byrne and his partner Nadia Corp of the University of St. Andrews have explored the brains and behaviors of eighteen species of primates, and they found a striking connection. The larger the animal’s neocortex, the better they were at deceiving their fellow primates in everyday situations.
Homo sapiens lies all the time. As individuals, we discover the nature of the lie at around the age of three or four and, from then on, it is a natural companion without which only very few can imagine living. You can’t really conceive of a modern, well-functioning society without the lie.
Read all the details on these technologies at Salon.
Almost everyone has experienced one memory triggering another, but explanations for that phenomenon have proved elusive. Now, University of Pennsylvania researchers have provided the first neurobiological evidence that memories formed in the same context become linked, the foundation of the theory of episodic memory.
“Theories of episodic memory suggest that when I remember an event, I retrieve its earlier context and make it part of my present context,” Kahana said. “When I remember my grandmother, for example, I pull back all sorts of associations of a different time and place in my life; I’m also remembering living in Detroit and her Hungarian cooking. It’s like mental time travel. I jump back in time to the past, but I’m still grounded in the present.”
Original paper here.
Psychological theories of memory posit that when people recall a past event, they not only recover the features of the event itself, but also recover information associated with other events that occurred nearby in time. The events surrounding a target event, and the thoughts they evoke, may be considered to represent a context for the target event, helping to distinguish that event from similar events experienced at different times. The ability to reinstate this contextual information during memory search has been considered a hallmark of episodic, or event-based, memory. We sought to determine whether context reinstatement may be observed in electrical signals recorded from the human brain during episodic recall.
She said, ‘I’m so afraid.’ And I said, ‘why?,’ and she said, ‘Because I’m so profoundly happy…Happiness like this is frightening.’ I asked her why and she said, ‘They only let you be this happy if they’re preparing to take something from you.
“
| — | Khaled Hosseini (via quercetum) |
Scientists at Rensselaer Polytechnic Institute have found that when just 10 percent of the population holds an unshakable belief, their belief will always be adopted by the majority of the society.
Have to say, I was very interested in the article (and I’m sure Gladwell is smiling too), but I was actually a bit let down. It seems to rely too much on abstractions and so may have moved too far away from reality. For instance, most people probably don’t change their minds simply after meeting two people with the opposing view, and the degree to which our beliefs are malleable varies from person and subject. So, all in all, an interesting piece - but I’m waiting for the real-life followup.
“The path, in the context of evolutionary enlightenment, is, at least in theory, quite simple,” writes spiritual teacher, Andrew Cohen in The Huffington Post. “It is a journey from identification with ego to identification with the evolutionary impulse. It is a radical transformation of our relationship to the human experience, from one that is fundamentally negative, narcissistic, compulsive, and rigid to one that is inherently positive, liberated, consciously creative, and perpetually evolving.”
“In an evolutionary context,” Cohen observes, “the expression of the enlightened or liberated self is perpetual development in time. So if the individual is not developing in a measurable and discernible way, that means that he or she is stagnating in the emotional and psychological prison of unenlightenment that is the individual and collective ego.”
What Does It Mean to Be You?
Character is something we tend to think of as a static, enduring quality, and yet we glorify stories of personal transformation. In reality, our essence oscillates between a set of hard-wired patterns and a fluid spectrum of tendencies that shift over time and in reaction to circumstances. This is exactly what journalist Julian Baggini, co-founder of The Philosopher’s Magazine, tries to reconcile in The Ego Trick: In Search of the Self.
Age-related cognitive decline — that moment of ‘where did I leave my keys’ that happens more and more as we age — has been turned around in monkeys. Scientists transformed aging brain cells into young ones, capable of sustaining working memory, through which the brain is able to hold a thought for a short period of time.
