Slashdot Mirror
'Predecessor' Neurons to Human Brain Discovered
Yale researchers claim to have found the very first neurons in what eventually becomes the human brain. Developed before most anything else, these neurons are in place just 31 days after fertilization. From the article: "We hypothesize that these predecessor neurons may be a transient population involved in determining the number of functional radial units including the human specific regions of the cerebral cortex mediating higher cognitive functions," Rakic said. "As a next step it is essential to determine their neural stem cell lineage, pattern of gene expression, developmental role and eventual fate."
When your blood alcohol comes down you'll probably realise that you're not going to find much likeness regarding brain development between humans and C. Elegans. Because they don't have much of a brain... in fact they're lacking circulatory and respiratory systems as well.
WRONG. Maybe worms don't have a "brain" as we know it, but they are a very good model for nervous systems. Nearly 1/3 of the cells of C. elegans worms are neurons, and the entire lineage of every cell in the adult worm is well mapped. Worms are a good animal model system, and combined with research from flies (Drosophila) and mice, much is known about neural development. Since we are humans, clearly, we are often most interested specifically in what is know about our own development. So the Yale study, while not entirely novel, certainly is an important study in a long line of great research to help us understand the development and wiring of the brain.
I didn't claim that the brain cells of elegans was known- they haven't properly got one, as you point out. I was saying that the fate of ALL cells in the elegans zygote are known- that you can trace the development of a single cell from ferticlization to adult. If you want to know what the cell in the fourth quadrant upper right is (i don't know the mapping schema- I do trees) you can go look it up somewhere, and conversely, if you want to know which cell in the blastocyte produced the segment you're looking at under the microscope you can find that information as well. I had thought this proceudre had been done on humans as well, but I was apparently wrong, that or this article is old news. It is /. after all.
Uh, "if it looks roughly mouse-shaped according to my infra-red sensitive pit, eat it"? --Chris Burke 09-08-10
The difference is that the Bible and the teachings of the Apostles (and natural law, in many cases) explicitly tell us that extramarital sex, homosexual acts, etc. are wrong; but the Bible doesn't say anything about what happens to unbaptized children who die.
Unbaptized children don't have justifying grace (which is normally received through baptism), and so they shouldn't be able to go to heaven. On the other hand, they haven't personally sinned, so they shouldn't go to hell either. One theory that attempts to resolve this problem is that unbaptized babies go to Limbo, which is a place without the supernatural happiness of heaven (since they don't have justifying grace), but with perfect natural happiness (since they don't deserve punishment). So unbaptized babies would live for eternity happier than anyone ever did on Earth. This is pretty nice, and I tend to agree with the Limbo idea. The good thing about this theory is that Limbo at least has a Biblical parallel in the Limbo of the Fathers, where good people from Old Testament times went until the opening of heaven to them by Christ (Luke 16:22).
On the other hand, maybe God gives unbaptized babies something similar to a baptism of desire, and so they can go to heaven... This is a bit more speculative than the Limbo idea, but not impossible.
I remember reading something similiar ages ago, though the projected date was somewhere between 2020 and 2025, allowing for variances in the actual rate of progess before a desktop-grade PC would reach the roughly 1 billion billion ops/sec @ 1 petabyte storage that was the stated theoretical digital equivalent.
From a 1993 article in Nanobiology Magazine:
Processing Power
The processing power of the system of neurons in the brain can be roughly evaluated by the number of events which may occur in this system per second. The number of neurons is about 10e+10 and their switching time is about 10e+2 sec, so the number of events per second is about 10e+12. This figure is comparable with the number of operations per second in massively parallel computer systems approaching the teraop barrier. Thus, the information processing power of the system of neurons does not drastically exceed that available through modern microelectronic technology. In the expanded construction suggested in [2] the number of binary events per second may reach 10e+23 to 10e+25. However, as in all massively parallel systems a problem arises whether a substantial portion of this estimated raw computational power can be effectually utilized.
Poster's note: Obviously, many of these connections are utilized for non-cognitive functions are are tied in to motor skills. I believe the original figure I quoted (10e+18) is meant to represent available capacity outside of pure maintenance functions (i.e., it does not include the neural equivalent of TCP overhead, etc. [depends on whether you're running WinDome or CerebRIX, actual mileage may vary depending upon the amount of OEM RAM you came with])
Come on... Laugh! You know it was funny ^.^
Memory Capacity
The capacity of the long term human memory is virtually unlimited. According to von Neumann [5], estimated by the amount of information which can be transferred to a human brain during its lifetime, the lower bound of this capacity is about 2.8× 1020 bits. To be stored in the brain of about 103 cm3 this requires density of informational storage about at least 3× 1017 bits/cm-3. The time of content-addressable retrieval is rather short and essentially independent from the amount of stored information. Once recorded, information in the brain is supposed to be retained permanently. Thus, images don't fade with time and can be easily recognized over decades.
This last is an oversimplifcation without solid root in neurobiology. Due to a browser crash, I lost what I'd just added here, but it is easily shown that the brain most certainly performs it's own regular disk-maintnance (delete old files, defrag, index and cross-correlate data, and delete cookies and other temporary files that have been determined to be irrelvant though indexing and defragging - such as excatly what you paid for breakfast at McD's last Tuesday or what color socks the bosses' secretary wore yesterday) and does not possess anywhere the necessary capacity to store in digital detail every event of every day.
From a PsychologyToday article:
"By the year 2020, your $1,000 personal computer will have the processing power of the human brain--20 million billion calculations per second (100 billion neurons times 1,000 connections per neuron times 200 calculations per second per connection). By 2030, it will take a village of human brains to match a $1,000 computer. By 2050, $1,000 worth of computing will equal the processing power of all human brains on earth."
This seems to be a generally expected figure, though t
"Inveniemus Viam Aut Faciemus" 'We will find a way... Or we will make one!' --Hannibal of Carthage
Since pederasts tend to be homosexuals
FYI this is false. Heterosexual men are vastly more likely to abuse children (including boys) than homosexual men.