Dynamic functional connectivity (DFC)

Where static functional connectivity averages a whole scan into one correlation matrix, DFC asks how that correlation structure changes moment to moment. A tapered window slides across the time series, producing a sequence of connectivity matrices; these are clustered into a handful of recurring brain states, and the brain’s traffic between them — how long it dwells in each, how often it switches — becomes the object of study (Allen et al. 2014; Mooneyham et al. 2017).

Why the wiki has it

DFC is the central method of Treves et al. (2025), the wiki’s first first-hand study of breath-focused attention, and it is distinct enough from static resting-state FC to warrant its own page. The distinction is the whole point of that study: static connectivity gives the expected coarse picture (focused attention engages control/salience networks, anticorrelates the DMN), but the dynamic picture is where the interesting — and cautionary — findings live.

The recurring states

Across breath-meditation and rest, the clustering repeatedly recovers a small, replicable set of states: a hypoconnected state (low connectivity overall, thought to be an amalgam of infrequent states), a DMN-anticorrelated state, a hyperconnected state, and network-specific reductions (e.g. an SN-reduced state). Mooneyham et al. (2017) identified several of these around a breath exercise; Treves et al. recovered the same three plus one, and found the DMN-anticorrelated and hyperconnected states more prevalent, longer-dwelt, and more frequently switched-to during breath counting than rest.

The dynamic measures

Once windows are assigned to states, the standard readouts are dwell time (mean length of a continuous period in a state), number of episodes, proportion of time, and switch rate (transitions per unit time). These are what let DFC distinguish conditions that look similar statically — Treves et al.’s clearest task-vs-rest effects were in dwell time and switching, not in which states existed.

The caution the wiki attaches

DFC’s sensitivity cuts both ways. Its states replicate and its dynamic measures separate task from rest — but a state that marks a condition need not mark the behaviour the condition is meant to elicit. In Treves et al. the DMN-anticorrelated state best separated breath counting from rest yet was unrelated to within-task on/off-task attention, and no state predicted individual differences in attentiveness. The method reliably finds structure; whether that structure is the psychological variable of interest is a separate, harder question. See treves-2025-breath-attention-dynamics.