Sunday, November 15, 2009

The 1000 Year Old Brain? Can They Last?

Aubrey de Grey claims that the first person to live 1,000 years is alive right now. Perhaps. But would anyone alive right now wish to live 1,000 years with a senile brain? Probably not. That is why it is so important to learn all we can about our brains, so that we can make the necessary improvements that will allow us to stay sharp, clear, and responsive to the many changes that the next 1,000 years will bring.

A World of Manics, Where No One is Depressed?
University of Maryland researchers have taken mice and knocked out PKCI/HINT1 genes -- resulting in mice that do not get depressed or anxious.
Wang said, "Although we don't yet know why the deletion of the gene altered the mood status of the mice, what we have learned about the importance of this gene in mood function and its involvement in human mental disorders is interesting. The protein encoded by this gene could be a potential drug target for development of diagnostic or therapeutic agents that one day might be used for depression, bipolar or schizophrenia disorders. In addition, the knockout mice might be useful as a model to study mania, as there is no other animal model available yet. __MNT
When thrown in the deep end of the pool, these PKCI/HINT1 knockout mice never gave up in despair, when all other mice simply rolled over and drowned. They were literally "never say die" mice. Imagine a world of such people.

Excitable Nerves, They All Said
Sometimes nerves can "excite themselves to death." This over-excitation of NMDA glutamate receptors may lead to Alzheimer's, Parkinson's, and multiple sclerosis -- among other neurodegenerative diseases.
....the N-methyl-D-aspartate receptor belongs to a family of cellular receptors that mediate excitatory nerve transmission in the brain.

Excitatory signals represent the majority of nerve signals in most regions of the human brain. One theory of causation in Alzheimer's, Parkinson's and multiple sclerosis posits that excessive amounts of the excitatory neurotransmitter, glutamate, can cause an overstimulation of glutamate receptors, including the NMDA receptor. Such excitotoxicity, the theory holds, can cause nerve-cell death and subsequent neurological dysfunction.

...The search is well under way for molecules that can shut down the NMDA receptor with much greater specificity. _MNT

Memories to Last 1000 Years?
Humans have short term memories (STMs) and long term memories (LTMs). Short term memory is necessary for maintaining a train of thought, or for remembering why you tied that string around your finger an hour or two ago. Long term memory is for remembering things that happened to you more than a day or so ago. These memories are formed and farmed out by the hippocampus, and the system usually works well for a lifespan of 70 or 80 years. But what happens when we live 1,000 years, and desperately need to remember something that happened 899 years ago?
Scientists have known that memories first form in the hippocampus and are later transferred to long-term storage in other parts of the brain. For some amount of time the memory resides both in the hippocampus and elsewhere in the brain. What’s not been known is how, after a few months or years, the memory is gradually cleared from the hippocampus.

Researchers have also debated the role of neurogenesis in learning and memory. The hippocampus is one of only two places in the adult brain where scientists know that new neurons form. On the basis of previous studies, many researchers think new neurons stabilize memory circuits or are somehow otherwise necessary to form new memories.

The new study suggests the opposite: Newborn neurons weaken or disrupt connections that encode old memories in the hippocampus.

Kaoru Inokuchi, a neuroscientist at the University of Toyama in Japan, and his colleagues used radiation and some genetic tricks to block neurogenesis in rats and mice that had been trained to fear getting a mild electric shock when placed in a particular cage. Control animals, with normal neurogenesis, eventually were able to bypass their hippocampi and retrieve the fear memory directly from long-term storage. But animals in which neurogenesis had been blocked still depended on the hippocampus to recall the fear memory, the researchers found.

Running on an exercise wheel, which boosts neurogenesis, also sped the rate at which old memories were cleared from the hippocampus. __Wired

Surviving the Addiction Bottleneck
The human brain has to survive through the treacherous years of childhood, adolescence, and early adulthood in order to gain the wisdom and experience to know how to live, and what to avoid like the plague. Children, adolescents, and young adults are prone to experimenting with drugs, alcohol, and high-risk / low reward behaviours. If the child becomes a crack whore or even an adolescent drunk or pothead like the US president, the 1,000 year prognosis can be very grim.

We need good ways of reversing the brain warp induced by early and habitual drug use.
Medical researchers led by Stephen Dewey at The Feinstein Institute for Medical Research and Dr. Jonathan Brodie of New York University School of Medicine recruited parolees who were cocaine dependent, each using an average of two grams of cocaine daily for nine years.

While half the participants in the study received a placebo powder mixed into their juice each day, half got a powder containing vigabatrin. After three months, 14 of the 50 study participants who got vigabatrin each day were able to abstain from cocaine use during the final three weeks of the study, compared with only 4 of the 53 who received the placebo. _MoneyTimes
It's a start. And in animals, the same drug reduces drug use for most every addictive substance. Of course, it will be harder to make up for the psychological neotenisation caused by poor childraising, abominable educational practises, and a horrifically dumbed down popular culture.

Does Evolution's Arrow Point to Smaller Human Brains?
Human populations that evolved nearer the equator ended up with generally smaller brains, and typically with lower IQ, than human populations that evolved farther from the equator. Anthropologist John Hawks says that the future may be bringing yet smaller brains to the entire global population.
“We know the brain has been evolving in human populations quite recently,” University of Wisconsin-Madison (UWM) paleoanthropologist John Hawks explains, quoted by LiveScience.

“When it comes to recent evolutionary changes, we currently maybe have the least specific details with regard [to] the brain, but we do know from archaeological data that pretty much everywhere we can measure – Europe, China, South Africa, Australia – that brains have shrunk about 150 cubic centimeters, off a mean of about 1,350. That's roughly 10 percent. As to why is it shrinking, perhaps in big societies, as opposed to hunter-gatherer lifestyles, we can rely on other people for more things, can specialize our behavior to a greater extent, and maybe not need our brains as much,” the expert adds. _Softpedia
Modern cultures of hyper-specialisation may lead to even greater shrinking of the human brain. That could be bad for that 1,000 year lifespan.

Smaller brains are typically less intelligent, and will probably be less able to adapt to the lightspeed changes that will hit human populations like truckloads of bricks, every few years to every few dozen years.

Cross-posted at Al Fin


Monday, November 09, 2009

Stem Cell Advances

Any adult cell can become a stem cell. This is a striking finding from the Cambridge, Mass. researchers.
“Essentially, all cells have the potential to become pluripotent. It is something that seems to happen to the cells under these conditions stochastically — that is, in a continuous, but probabilistic fashion,” Jaenisch explains. _Softpedia

Stem cell treatment restores limb function in rats with cervical spine injuries. The UCI team used human embryonic stem cells (pre-oligodendrocytes) that "rebuilt myelin, stopped tissue death and triggered nerve fiber regrowth".

Patients with advanced leukemia successfully treated with stem cells. Of the 58 patients, 35% survived 3 years -- an exceptionally good result for patients at such an advanced stage.

New technique developed to separate "safe" from "unsafe" stem cells before therapy. Stem cells vary in their likelihood to grow out of control and cause malignancies. "Undifferentiated" stem cells are more likely to lose control of growth.
Scientists from Invitrogen and the Buck Institute for Age Research, located in Novato, California, collaborated in developing this innovative solution that depletes greater than 99% of undifferentiated human embryonic stem cells from differentiated populations. They are presenting data on this new technology at the International Society for Cellular Therapy Meeting in San Diego. __LabmateOnline

Stem cells provide the bricks and mortar for constructing human tissues and organs. We are just beginning to learn how to create them, and to use them safely and efficaciously. In ten years -- if the US biomedical system has not been completely destroyed by government intervention -- we will look back to the present, amazed that human medicine was ever so primitive and hopelessly ineffective.


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