>>> context weblog
sampling new cultural context
| home | site map | about context | donate | lang >>> español - català |
friday :: april 28, 2006
how brain cells work: nerve cells talk in pairs

When a group of people tries to decide how to carry out an important task, it is sometimes said that the pivotal discussions do not happen in large, well-attended meetings, but in one-on-one conversations around the water cooler. It turns out that among individual neurons in our brains, the same may hold true.

Likening the process to the sort of casual conversations one might have at a cocktail party, William Bialek and his research team have found that retinal ganglion cells, the nerve cells along the back of our eyes that transmit visual signals to the brain, organize their actions based on communications they have with other individual cells rather than on group-style discussions. The findings, derived from experiments with and mathematical models of groups of 40 cells in the retinas of salamanders, could shed light on how brain cells work as a team.

'We have found that it is possible to understand the group behavior of neural cells based solely on knowledge of these pair interactions,' said Bialek, who wrote the research paper with Princeton colleagues Michael Berry, Ronen Segev and Elad Schneidman. 'From these pair-wise communications, a consensus emerges as to what message will be sent from the eye to the brain. But it comes from many small discussions, not one large one.'

'By eavesdropping on the 'conversations' of individual nerve cells, these researchers learned to predict how small groups of nerve cells in the eye would behave,' said biophysicist C. John Whitmarsh. 'This really is a fantastic result, and could help us understand how brain cells work together to make decisions.'

'It seems that cells at the cocktail party talk primarily, perhaps exclusively, in pairs alone. No one belongs to a group, or takes dictation from a leader, but everyone bases their behavior on what we might call 'informed pair conversations.' They participate in as many of them as they can, listen as much as they can, then act,' Schneidman said.

According to this analogy, the retinal cells would transmit messages based on the information culled from these 'conversations.' However, Bialek said, as at any party, there are subtleties at work as well. 'Just as you might know from past experience that you tend to sympathize with one party guest quite often, but are put off by another, the opinions you draw from different conversations are not all weighted equally,' he said. 'You might nod politely at one person's argument, while agreeing strongly with another, even though they had both come down on the same side of an issue. Nerve cells seem to react to one another in the same way.'

'The evidence pointed us to a more startling discovery, which is that buried in the apparent randomness there are subtle relationships between pairs in the group, and you can actually determine what the group's decision will be, based solely on an awareness of these relationships between pairs,' Berry said. 'Our model does not exclude the possibility that larger groupings within the 40 cells exist. What it shows is that either way, they do not need to be considered to predict the final outcome.' >from *Researchers find nerve cells talk in pairs*. April 20, 2006

related context
groups perform better than the best individuals at solving complex problems. effects of group size: 'groups of three, four, or five perform better on complex problem solving than the best of an equivalent number of individuals.' april 23, 2006
> disorder-induced synchronization. april 14, 2006
> physics of friendship. 'by comparing people to mobile particles randomly bouncing off each other, scientists developed a new model for social networks. the model fits with empirical data to naturally reproduce the community structure, clustering and evolution of general acquaintances and even sexual contacts.' march 10, 2006
> how the brain makes a whole out of parts. 'beginning to reveal how large networks of neurons in the brain extract meaning from the eye image.' january 17, 2006
> why the brain has gray and white matter. 'brain functionality benefits from high synaptic connectivity and short conduction delays.' january 27, 2006
> steps to integrate new neurons into brain's existing operations. december 22, 2005
> swarm intelligence. 'a system whereby the collective behaviours of (unsophisticated) agents interacting locally with their environment cause coherent functional global patterns to emerge.' may 20, 2005
> how animals coordinate their actions. 'group coordination arises naturally from two basic instincts: the need to stay in a group; and the desire by some individuals to act on their own information about where to go.' march 18, 2005
> cooperation evolution. october 8, 2003
> ants community: a perceptual achievement. 'what seems to matter to an ant is the pattern of interactions it experiences rather than a particular message or signal transferred at each interaction.' may 7, 2003
> commons-based peer production in the digitally networked environment. 'groups of individuals successfully collaborate on largescale projects following a diverse cluster of motivational drives and social signals, rather than either market prices or managerial commands.' december 19, 2002

it takes two to speak the truth one to speak and another to hear
Henry Thoreau

sonic flow
from the eye to the brain [stream]
from the eye to the brain [download]

| permaLink

> context weblog archive
december 2006
november 2006
october 2006
september 2006
august 2006
july 2006
june 2006
may 2006
april 2006
march 2006
february 2006
january 2006
december 2005
november 2005
october 2005
september 2005
august 2005
july 2005
june 2005
may 2005
april 2005
march 2005
february 2005
january 2005
december 2004
november 2004
october 2004
september 2004
august 2004
july 2004
june 2004
may 2004
april 2004
march 2004
february 2004
january 2004
december 2003
november 2003
october 2003
june 2003
may 2003
april 2003
march 2003
february 2003
january 2003
december 2002
november 2002
october 2002
july 2002
june 2002
may 2002
april 2002
march 2002
february 2002
january 2002
countdown 2002
december 2001
november 2001
october 2001
september 2001
august 2001

more news in
> sitemap


context archives all www
   "active, informed citizen participation is the key to shaping the network society. a new 'public sphere' is required." seattle statement
| home | site map | about context | donate | lang >>> español - català |
03 http://straddle3.net/context/03/en/2006_04_28.html