fMRI evidence that human brain has (functional) small world properties

A Resilient, Low-Frequency, Small-World Human Brain Functional Network with Highly Connected Association Cortical Hubs (Achard et al., 2006)

A study on network properties of the whole brain (functional connectivity data from fMRI)… interesting to see this type of work published in J. Neurosci. Building on previous fMRI/whole brain connectivity studies, the authors use a set of wavelet basis functions to estimate the correlations between different anatomical regions.

Also includes some analyses on resiliency of the system (via a metric like “largest connected cluster”) to random and targeted attack (ie. node deletion). It would be neat if they also did some analysis of common stroke damage. I would think that a stroke probably doesn’t qualify as a “targeted attack”, in the traditional sense, but, due to the predefined structure of the major circulatory structures (eg. circle of Willis), there are likely regions that are near the most commonly blocked arteries, etc. Perhaps someone with some medical qualifications could weigh in here?

There is also a nice discussion of why the human brain does not appear to be a scale-free network: That nodes do not seem to follow the “rich-get-richer” rule of preferential attachment. Evolutionarily recent structures like prefrontal seem to be among the hubs of the system and older structures like limbic regions do not dominate. Here’s a picture of the connectivity map from the paper:
Connectivity map

Full abstract after the jump.
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Neuroscience family tree

Some folks have created NeuroTree to document the advisor-advisee relationships (i.e., “so-and-so was a grad student of that guy, and that guy postdoc’d with someone else”) of neuroscience. With this information, one can draw “family trees” like this.

Here is the FAQ.

Importantly, this is a collaborative effort, so add your name if it’s not there already.

-John O’Leary

Evolutionary psychology of gossip

Have You Heard? Gossip Turns Out to Serve a Purpose – New York Times

From the article:

Gossip not only helps clarify and enforce the rules that keep people working well together, studies suggest, but it circulates crucial information about the behavior of others that cannot be published in an office manual. As often as it sullies reputations, psychologists say, gossip offers a foothold for newcomers in a group and a safety net for group members who feel in danger of falling out.