Parkinson’s disease is classically associated with abnormal rhythmic activity in cortico-basal ganglia circuits, especially excessive beta-band synchronization. Yet brain activity is not made only of regular oscillations. It also contains brief, irregular, aperiodic bursts that propagate across regions and may reflect the brain’s capacity to flexibly coordinate distributed activity.
In this study, in collaboration with Alexandre Eusebio and Pierre Paolo Sorrentino in Marseille, we investigated how L-Dopa modifies these aperiodic burst dynamics in people with Parkinson’s disease. Using resting-state recordings from the subthalamic nucleus during DBS monitoring, together with motor EEG, we. compared brain activity before and after levodopa treatment in 11 patients. They focused on neuronal avalanches: short, spatially distributed bursts of activity whose size, duration, and propagation patterns can be used to characterize large-scale brain dynamics.
The study found that, in the OFF-medication state, avalanches were shorter and smaller. After L-Dopa, avalanches became fewer but longer and larger, suggesting a shift toward broader propagation of activity across the recorded network. Importantly, the authors also reconstructed avalanche transition matrices to quantify how bursts spread between recording contacts. Under L-Dopa, the probability of avalanche propagation increased within and between the subthalamic nucleus and motor cortex.
The key result is clinical: L-Dopa-induced increases in avalanche propagation correlated with individual motor improvement. In other words, the patients who benefited more clinically from L-Dopa also showed stronger changes in how aperiodic bursts spread through the subthalamo-cortical motor network. This suggests that dopaminergic treatment may improve motor function not only by suppressing pathological rhythms, but also by restoring the brain’s ability to propagate transient, flexible activity patterns.
A useful way to summarize the contribution is: Parkinsonian motor improvement may depend not only on reducing abnormal oscillations, but also on reopening channels for aperiodic, distributed neural communication. L-Dopa appears to reshape the dynamics of spontaneous bursts so that activity can travel more effectively across the motor network.
This work contributes to a broader dynamical view of Parkinson’s disease. Rather than focusing only on spectral power or fixed connectivity, it highlights moment-to-moment burst propagation as a candidate marker of treatment response. By linking individual clinical improvement to changes in avalanche dynamics, the study suggests that aperiodic burst measures could help characterize how dopaminergic therapy restores functional communication in Parkinsonian brain circuits.
To know more:
- Agouram, H., Neri, M., Angiolelli, M., Depannemaecker, D., Bahuguna, J., Schwey, A., Régis, J., Carron, R., Malfait, N., Eusebio, A., Daucé, E., & Sorrentino, P. (2025). L-Dopa-induced changes in aperiodic bursts dynamics relate to individual clinical improvement in Parkinson’s disease. npj Parkinson’s Disease, 11, 158. https://doi.org/10.1038/s41531-025-01024-w.