A Funky Visual Illusion: What's the Frequency?

From my own experimentation, the frequency matters.

You can only see this optical illusion if you shake your head (I’m serious) 😂 pic.twitter.com/WhtZ1b0r4t

— Dr Michelle Dickinson (@medickinson) January 10, 2019

(Tip of the cap to Jenna Walrath.)

"Frequency-Based Brain Networks: From a Multiplex Framework to a Full Multilayer Description"

One of my papers just came out in final form. Here are some details.

Title: Frequency-Based Brain Networks: From a Multiplex Framework to a Full Multilayer Description

Authors: Javier M. Buldú and Mason A. Porter

Abstract: We explore how to study dynamical interactions between brain regions by using functional multilayer networks whose layers represent different frequency bands at which a brain operates. Specifically, we investigate the consequences of considering the brain as (i) a multilayer network, in which all brain regions can interact with each other at different frequency bands; and as (ii) a multiplex network, in which interactions between different frequency bands are allowed only within each brain region and not between them. We study the second-smallest eigenvalue λ2 of the combinatorial supra-Laplacian matrix of both the multiplex and multilayer networks, as λ2 has been used previously as an indicator of network synchronizability and as a biomarker for several brain diseases. We show that the heterogeneity of interlayer edge weights and, especially, the fraction of missing edges crucially modify the value of λ2, and we illustrate our results with both synthetic network models and real data obtained from resting-state magnetoencephalography. Our work highlights the differences between using a multiplex approach and a full multilayer approach when studying frequency-based multilayer brain networks.

Bonus: This paper has an easter egg. Can you find it? (Hint: This is Spinal Tap.)

Awesome Optical Illusion: Bathroom Tile Edition

Versions of this optical illusion (much less elaborate variants of it) appear to be ubiquitous in restaurant bathroom tiles. :)

Terrific optical illusion by Victoria Skye. @RichardWiseman @chriscfrench pic.twitter.com/IeSFupAcfU

— Martin S Taylor (@martinstaylor) August 7, 2017

Lots of Discussions, But Which of Them Were Useful?

This paper has a gem in its acknowledgements.

(Tip of the hat to Robert Garisto for his tweet, which provided enough fodder for Google.)

"Task-Based Core-Periphery Organization of Human Brain Dynamics"

Another of my papers just came out today, though I have to say that putting 12 pieces of supplementary information (8 figures, 3 tables, and supplementary text) as 13 separate files is absolutely ridiculous. It also led to some botching on the part of the journal --- such as in the table numbering in the .pdf versions and a messed-up reference in the caption of a table in the .pdf version --- and we never had the chance to do anything about it because this journal doesn't do page proofs. Sigh... Anyway, here is a combined version of the .pdf files that my postdoc Sang Hoon Lee assembled, and here is the accepted preprint version of the paper.


And now for the details about the paper itself...


Title: Task-Based Core-Periphery Organization of Human Brain Dynamics

Authors: Danielle S. Bassett, Nicholas F. Wymbs, M. Puck Rombach, Mason A. Porter, Peter J. Mucha, and Scott T. Grafton

Abstract: As a person learns a new skill, distinct synapses, brain regions, and circuits are engaged and change over time. In this paper, we develop methods to examine patterns of correlated activity across a large set of brain regions. Our goal is to identify properties that enable robust learning of a motor skill. We measure brain activity during motor sequencing and characterize network properties based on coherent activity between brain regions. Using recently developed algorithms to detect time-evolving communities, we find that the complex reconfiguration patterns of the brain's putative functional modules that control learning can be described parsimoniously by the combined presence of a relatively stiff temporal core that is composed primarily of sensorimotor and visual regions whose connectivity changes little in time and a flexible temporal periphery that is composed primarily of multimodal association regions whose connectivity changes frequently. The separation between temporal core and periphery changes over the course of training and, importantly, is a good predictor of individual differences in learning success. The core of dynamically stiff regions exhibits dense connectivity, which is consistent with notions of core-periphery organization established previously in social networks. Our results demonstrate that core-periphery organization provides an insightful way to understand how putative functional modules are linked. This, in turn, enables the prediction of fundamental human capacities, including the production of complex goal-directed behavior.

Mathematics Ability Requires Crosstalk in the Brain

This is a very cool study and, I think, highly amenable to further work that builds on this using methods along the lines of what my collaborators and I have been using to examine learning of motor skills.

But, even more importantly, the name of a center that include's the study's lead author --- "Center for Vital Longevity" --- makes me giggle. :) I guess everything really is bigger in Texas...

(Tip of the cap to MoMath: The Museum of Mathematics and whoever does their Facebook posts.)

Is Pixar paying attention to science?

Clearly, the folks at Pixar need to read about this scientific study that uses fMRI data to determine what type of car fronts males consider attractive.

Choice quote: Our findings allow the recommendation to give the grille a friendly expression whereas the headlights should rather look aggressive.

Also, I can't help wondering what kind of car Gary Numan would feel safest in?

"Dynamic Reconfiguration of Human Brain Networks During Learning"

My new paper on braaaaaaains came out in the early edition of Proceedings of the National Academy of Sciences two weeks ago, and I am finally blogging about it and posting a link because the page numbers have finally been assigned.

Title: Dynamic Reconfiguration of Human Brain Networks During Learning

Authors: Danielle S. Bassett, Nicholas F. Wymbs, Mason A. Porter, Peter J. Mucha, Jean M. Carlson, and Scott T. Grafton

Abstract: Human learning is a complex phenomenon requiring flexibility to adapt existing brain function and precision in selecting new neurophysiological activities to drive desired behavior. These two attributes -- flexibility and selection -- must operate over multiple temporal scales as performance of a skill changes from being slow and challenging to being fast and automatic. Such selective adaptability is naturally provided by modular structure, which plays a critical role in evolution, development, and optimal network function. Using functional connectivity measurements of brain activity acquired from initial training through mastery of a simple motor skill, we investigate the role of modularity in human learning by identifying dynamic changes of modular organization spanning multiple temporal scales. Our results indicate that flexibility, which we measure by the allegiance of nodes to modules, in one experimental session predicts the relative amount of learning in a future session. We also develop a general statistical framework for the identification of modular architectures in evolving systems, which is broadly applicable to disciplines where network adaptability is crucial to the understanding of system performance.

Three Fascinating Articles

I just read three fascinating articles on CNN.com.

The first one discusses tweeting directly using one's brain to form the letters.

The second discusses differences between men and women with respect to sexual orientation being continuous versus discrete. (There are other things in the article too, but this is what I found most interesting.) Apparently, a bunch of studies are suggesting that it seems to be much more of a continuum in women than in men (and also perhaps that it is more common for a woman to experience a change in location over time).

The third discusses the new Star Trek film. (If you haven't gotten the allusion yet, let's just say that this article is fascinating in a somewhat different manner than the other two.)