Strength-dependent perturbation of wholebrain model working in different regimes reveals the role of fluctuations in brain dynamics

PERL, YONATAN SANZ; ESCRICHS, ANIRA; TAGLIAZUCCHI, ENZO; KRINGELBACH, MORTEN L.; DECO, GUSTAVO

PLOS COMPUTATIONAL BIOLOGY

PUBLIC LIBRARY SCIENCE

Año: 2022 vol. 18

1553-734X

Despite decades of research, there is still a lack of understanding of the role and generating mechanisms of the ubiquitous fluctuations and oscillations found in recordings of brain dynamics. Here, we used whole-brain computational models capable of presenting different dynamical regimes to reproduce empirical data´s turbulence level. We showed that the model´s fluctuations regime fitted to turbulence more faithfully reproduces the empirical functional connectivity compared to oscillatory and noise regimes. By applying global and local strength-dependent perturbations and subsequently measuring the responsiveness of the model, we revealed each regime´s computational capacity demonstrating that brain dynamics is shifted towards fluctuations to provide much-needed flexibility. Importantly, fluctuation regime stimulation in a brain region within a given resting state network modulates that network, aligned with previous empirical and computational studies. Furthermore, this framework generates specific, testable empirical predictions for human stimulation studies using strength-dependent rather than constant perturbation. Overall, the whole-brain models fitted to the level of empirical turbulence together with functional connectivity unveil that the fluctuation regime best captures empirical data, and the strength-dependent perturbative framework demonstrates how this regime provides maximal flexibility to the human brain. Copyright: