I read, somewhere, Professor Marchal, that it was the "spindle cells" in the 
brain that pushed the smarter creatures on this planet into high gear, so to 
speak, not so much glial, unless we are describing the same thing, primates, 
whales, dolphins, have spindle cells, and why this makes a difference I don't 
know. For no rational reason, my limbic system is urging me (?) to include in 
this email, the first stanza from Hyperactive, by Thomas Dolby. It adds nothing 
to this discussion, yet here it is, because it seems somehow, fitting.



At the tender age of three
 I was hooked to a machine
 Just to keep my mouth from spouting junk
 Must have took me for a fool
 When they chucked me out of school
 'Cause the teacher knew I had the funk




-----Original Message-----
From: Bruno Marchal <marc...@ulb.ac.be>
To: everything-list <everything-list@googlegroups.com>
Sent: Mon, Oct 28, 2013 1:53 pm
Subject: Re: Neuroscientists discover new 'mini-neural computer' in the brain




On 28 Oct 2013, at 16:52, Craig Weinberg wrote:


http://medicalxpress.com/news/2013-10-neuroscientists-mini-neural-brain.html


Dendrites, the branch-like projections of neurons, were once thought to be 
passive wiring in the brain. But now researchers at the University of North 
Carolina at Chapel Hill have shown that these dendrites do more than relay 
information from one neuron to the next. They actively process information, 
multiplying the brain's computing power.

"Suddenly, it's as if the processing power of the brain is much greater than we 
had originally thought," said Spencer Smith, PhD, an assistant professor in the 
UNC School of Medicine.

His team's findings, published October 27 in the journal Nature, could change 
the way scientists think about long-standing scientific models of how neural 
circuitry functions in the brain, while also helping researchers better 
understand neurological disorders.

"Imagine you're reverse engineering a piece of alien technology, and what you 
thought was simple wiring turns out to be transistors that compute 
information," Smith said. "That's what this finding is like. The implications 
are exciting to think about."

Axons are where neurons conventionally generate electrical spikes, but many of 
the same molecules that support axonal spikes are also present in the 
dendrites. Previous research using dissected brain tissue had demonstrated that 
dendrites can use those molecules to generate electrical spikes themselves, but 
it was unclear whether normal brain activity involved those dendritic spikes. 
For example, could dendritic spikes be involved in how we see?

The answer, Smith's team found, is yes. Dendrites effectively act as 
mini-neural computers, actively processing neuronal input signals themselves.

Directly demonstrating this required a series of intricate experiments that 
took years and spanned two continents, beginning in senior author Michael 
Hausser's lab at University College London, and being completed after Smith and 
Ikuko Smith, PhD, DVM, set up their own lab at the University of North 
Carolina. They used patch-clamp electrophysiology to attach a microscopic glass 
pipette electrode, filled with a physiological solution, to a neuronal dendrite 
in the brain of a mouse. The idea was to directly "listen" in on the electrical 
signaling process.

"Attaching the pipette to a dendrite is tremendously technically challenging," 
Smith said. "You can't approach the dendrite from any direction. And you can't 
see the dendrite. So you have to do this blind. It's like fishing if all you 
can see is the electrical trace of a fish." And you can't use bait. "You just 
go for it and see if you can hit a dendrite," he said. "Most of the time you 
can't."

Once the pipette was attached to a dendrite, Smith's team took electrical 
recordings from individual dendrites within the brains of anesthetized and 
awake mice. As the mice viewed visual stimuli on a computer screen, the 
researchers saw an unusual pattern of electrical signals – bursts of spikes – 
in the dendrite.

Smith's team then found that the dendritic spikes occurred selectively, 
depending on the visual stimulus, indicating that the dendrites processed 
information about what the animal was seeing.

To provide visual evidence of their finding, Smith's team filled neurons with 
calcium dye, which provided an optical readout of spiking. This revealed that 
dendrites fired spikes while other parts of the neuron did not, meaning that 
the spikes were the result of local processing within the dendrites.

Study co-author Tiago Branco, PhD, created a biophysical, mathematical model of 
neurons and found that known mechanisms could support the dendritic spiking 
recorded electrically, further validating the interpretation of the data.

"All the data pointed to the same conclusion," Smith said. "The dendrites are 
not passive integrators of sensory-driven input; they seem to be a 
computational unit as well."

His team plans to explore what this newly discovered dendritic role may play in 
brain circuitry and particularly in conditions like Timothy syndrome, in which 
the integration of dendritic signals may go awry.



"This revealed that dendrites fired spikes while other parts of the neuron did 
not, meaning that the spikes were the result of local processing within the 
dendrites."

Yep, looks like neurons have a nervous system of their own now. Still think 
that consciousness is a product of the brain?




I refer you to my rare posts where I suggest that the level is the molecular 
level, and should include the glial cells, which in my opinion (from diverse 
reading) handle to information.


I also defend the idea that an amoeba, by being unicellular, can be seen as a 
cell being simultaneously a digestive cell, a muscular cells, a liver cell, a 
kidney cell, a bone cell, and a brain cell. 


Amoebas are not completely stupid and deserve respects, and so are any each of 
our own cells, despite those cells in multicellular organism have lost a bit of 
their freedom and universality to cooperate in what is ourself.


Again, the bold quote illustrates comp, and the fact that the level is lower 
than some thought.


Also with comp, consciousness is NOT a product of the mind. that's still too 
much an aristotelian way to express the "identity" thesis. Consciousness is not 
physical, it is the mental state of person associated to machines, when those 
person develop *some* true belief.


Bruno




 
http://iridia.ulb.ac.be/~marchal/



 



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