Imagine your brain is a bustling city with different neighborhoods, each responsible for different functions. In the city of Parkinson’s Disease (PD), dopaminergic medication has been found to affect the way these neighborhoods communicate and interact. But there’s more to the story! A team of scientists decided to investigate a lesser-known aspect of this communication: the non-oscillatory activity, which reflects the balance between excitation and inhibition. By analyzing brain activity recorded from 15 PD patients, both on and off medication, they discovered some fascinating results. First, they noticed a steepening of the ‘spectral slope’ in a specific region of the brain when patients were on medication, suggesting increased neuronal activity. Additionally, they found enhanced connectivity between different regions in the beta frequency range. And when they zoomed out to look at the big picture using graph theory analysis, they found that local connectivity in the central part of the brain was boosted by medication. However, at a global level, there were no significant differences in how the brain was organized. What’s even more intriguing is the connection researchers found between local neuronal activity and overall brain efficiency in the off medication condition. These findings shed new light on how dopamine medication affects brain dynamics in PD. If you want to dive deeper into this study and explore the fascinating research behind it, don’t forget to check out the full article!

Dopaminergic medication for Parkinson’s disease (PD) modulates neuronal oscillations and functional connectivity (FC) across the basal ganglia-thalamic-cortical circuit. However, the non-oscillatory component of the neuronal activity, potentially indicating a state of excitation/inhibition balance, has not yet been investigated and previous studies have shown inconsistent changes of cortico-cortical connectivity as a response to dopaminergic medication. To further elucidate changes of regional non-oscillatory component of the neuronal power spectra, FC, and to determine which aspects of network organization obtained with graph theory respond to dopaminergic medication, we analyzed a resting-state electroencephalography (EEG) dataset including 15 PD patients during OFF and ON medication conditions. We found that the spectral slope, typically used to quantify the broadband non-oscillatory component of power spectra, steepened particularly in the left central region in the ON compared to OFF condition. In addition, using lagged coherence as a FC measure, we found that the FC in the beta frequency range between centro-parietal and frontal regions was enhanced in the ON compared to the OFF condition. After applying graph theory analysis, we observed that at the lower level of topology the node degree was increased, particularly in the centro-parietal area. Yet, results showed no significant difference in global topological organization between the two conditions: either in global efficiency or clustering coefficient for measuring global and local integration, respectively. Interestingly, we found a close association between local/global spectral slope and functional network global efficiency in the OFF condition, suggesting a crucial role of local non-oscillatory dynamics in forming the functional global integration which characterizes PD. These results provide further evidence and a more complete picture for the engagement of multiple cortical regions at various levels in response to dopaminergic medication in PD.

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