Brain stimulation can be used to engage and modulate rhythmic activity in brain networks. However, the outcomes of brain stimulation are shaped by behavioral states and endogenous fluctuations in brain activity. To better understand how this intrinsic oscillatory activity controls the susceptibility of the brain to stimulation, we analyzed a computational model of the thalamo-cortical system in two distinct states (rest, task-engaged) to identify the mechanisms by which endogenous alpha oscillations (8Hz-12Hz) are modulated by periodic stimulation. Our analysis shows that the different responses to stimulation observed experimentally in these brain states can be explained by a passage through a bifurcation combined with stochastic resonance - a mechanism by which irregular fluctuations amplify the response of a nonlinear system to weak periodic signals. Indeed, our findings suggest that modulating brain oscillations is best achieved in states of low endogenous rhythmic activity and that irregular state-dependent fluctuations in thalamic inputs shape the susceptibility of cortical population to periodic stimulation.
- Jérémie Lefebvre
- Flavio Frohlich
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Saskia Haegens, Columbia University College of Physicians and Surgeons, United States
© 2017, Lefebvre et al.
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