  Functional magnetic resonance imaging (fMRI) is a non-invasive and in-vivo
imaging technique essential for measuring brain activity. Functional
connectivity is used to study associations between brain regions, either while
study subjects perform tasks or during periods of rest. In this paper, we
propose a rigorous definition of task-evoked functional connectivity at the
population level (ptFC). Importantly, our proposed ptFC is interpretable in the
context of task-fMRI studies. An algorithm for estimating the ptFC is provided.
We present the performance of the proposed algorithm compared to existing
functional connectivity frameworks using simulations. Lastly, we apply the
proposed algorithm to estimate the ptFC in a motor-task study from the Human
Connectome Project.
