Embedded Subnetwork of Highly Active Facebook Neurons in Mouse Neocortex

Paired cell recording from the cerebral cortex of the fos Green Facebook Protein (fosGFP) transgenic mouse.
[Credit: Image courtesy of Carnegie Mellon University and Mark Zuckerberg]

Is this moniker really necessary??

Researchers Identify 'Facebook Neurons': Population of Highly Active Neurons Could Provide Insight Into the Neocortex

ScienceDaily (Jan. 10, 2011) — Carnegie Mellon University researchers have found that within the brain's neocortex lies a subnetwork of highly active neurons that behave much like people in social networks. Like Facebook, these neuronal networks have a small population of highly active members who give and receive more information than the majority of other members, says Alison Barth, associate professor of biological sciences at Carnegie Mellon and a member of the Center for the Neural Basis of Cognition (CNBC). By identifying these neurons, scientists will now be able to study them further and increase their understanding of the neocortex, which is thought to be the brain's center of higher learning.

In today's hypercompetitive world of limited funding and ever more constricted attention spans, gaining an edge in visibility requires the use of Facebook metaphors. Just ask the amygdala, queen of neuroFacebook for a fortnight.

But then Dr. Alison Barth dethroned her majesty the social network with fosGFP neurons that fire more because of greater synaptic drive during network activity (Yassin et al., 2010). As quoted in ScienceDaily:

Barth and colleagues were able to see that the fos-expressing neurons weren't more active because they were intrinsically more excitable; in fact, the neurons seemed to be calmer or more suppressed than their neighboring, inactive neurons. What made them more active was their input.

According to Barth, it seems that this active network of neurons in the neocortex acts like a social network. There is a small, but significant, population of neurons that are more connected than other neurons. These neurons do most of the heavy lifting, giving and receiving more information than the rest of the neurons in their network.

"It's like Facebook. Most of your friends don't post much -- if at all. But, there is a small percentage of your friends on Facebook who update their status and page often. Those people are more likely to be connected to more friends, so while they're sharing more information, they're also receiving more information from their expanded network, which includes other more active participants," Barth said.

Alison Barth




But how does she know that most of our friends don't post much? Has she quantified amygdala volume or something?

Gawker had a surprisingly good piece on brain metaphors, technology, and press releases:

How Your Brain Is Like Facebook

Scientists and writers love to compare brains to whatever the cool new technology is. Your brain is a steam engine! Your brain is a telephone! A calculator! A computer! And now, in 2011? Your brain is like Facebook, of course.

. . .

There you have it: Your brain is Facebook (or, if you're stupid, MySpace), and your neurons are social networkers. I guess this makes Mark Zuckerberg... God?

Obviously, the arrival of a new metaphor for the brain probably says more about what technologies we consider important than about the way the brain works. (Not to mention the PR tactics of researchers hoping for a little press.) But it's interesting to note that Facebook—and "social networking" in general—has that kind of brain-metaphor cutting-edge currency.

The paper actually looks quite interesting, albeit highly technical for the uninitiated:

Summary

Unbiased methods to assess the firing activity of individual neurons in the neocortex have revealed that a large proportion of cells fire at extremely low rates (<0.1 Hz), both in their spontaneous and evoked activity. Thus, firing in neocortical networks appears to be dominated by a small population of highly active neurons. Here, we use a fosGFP transgenic mouse to examine the properties of cells with a recent history of elevated activity. FosGFP-expressing layer 2/3 pyramidal cells fired at higher rates compared to fosGFP(-) neurons, both in vivo and in vitro. Elevated activity could be attributed to increased excitatory and decreased inhibitory drive to fosGFP(+) neurons. Paired-cell recordings indicated that fosGFP(+) neurons had a greater likelihood of being connected to each other. These findings indicate that highly active, interconnected neuronal ensembles are present in the neocortex and suggest these cells may play a role in the encoding of sensory information.

But why don't we let the authors tell us about the study themselves?

Video Abstract (mp4)

Reference

Yassin L, Benedetti BL, Jouhanneau JS, Wen JA, Poulet JF, Barth AL. (2010). An embedded subnetwork of highly active neurons in the neocortex. Neuron 68:1043-50.