Shared spatial and temporal principles govern connectome dynamics across timescales

What is it about?

Our brain functions as a set of networks, regions that constantly coordinate with one another, and the pattern of which regions are connected shifts from moment to moment. We tracked these shifting patterns using two different ways of recording brain signals: fMRI and EEG. For years, many assumed both tools were capturing the same underlying brain activity at different temporal resolutions, with fMRI simply a slowed-down version of the EEG signal. Our study challenges that assumption. Recording fMRI and EEG from people simultaneously, we found the brain isn't running a single process. Instead, it runs many distinct coordinated processes at the same time: separate streams, each with its own character, all unfolding in parallel and independently of one another. It is as if, when we process language, the brain tracks the rapid flicker of individual sounds, the slower arrival of words, and the still-slower thread of meaning all at once, each on its own stream. What's striking is that these separate streams are built from the same spatial blueprint. The same basic patterns of connection appear in every stream, and they tend to play out in the same order. So while the streams are genuinely distinct processes, they share a common spatial layout and a common sequence. This suggests shared rules that let the brain weave its many parallel streams into one unified system.

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Photo by Growtika on Unsplash

Photo by Growtika on Unsplash

Why is it important?

The tools we use shape what we can learn about the brain and about cognition. If the connectome is genuinely many processes at once, we may need a more comprehensive approach that does not rely on a single modality such as EEG, MEG, or fMRI, so we can account for all of its parallel streams rather than just one, and fully understand human behavior and cognition.

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