Emerging hubs in phantom perception connectomics.

Area of Science:

• Neuroscience
• Network Science
• Medical Imaging

Background:

• Brain function relies on complex small-world networks with critical hubs for efficient information transfer.
• Brain disorders, including tinnitus, are linked to altered brain connectomes, affecting network topology and hub connectivity.
• Understanding these network alterations is crucial for developing targeted therapeutic strategies.

Purpose of the Study:

• To compare the network topology of binary and weighted brain networks in tinnitus patients versus healthy controls.
• To investigate alterations in network hubs across different oscillatory bands (delta, theta, alpha, beta, gamma).
• To elucidate the frequency band-dependent adaptive mechanisms the brain employs in response to auditory deafferentation.

Main Methods:

• Electroencephalography (EEG) data from 311 tinnitus patients and 256 controls were recorded.
• Source localization was performed using standardized low-resolution electromagnetic tomography (sLORETA).
• Network centrality measures identified hubs in binary and weighted networks across various frequency bands.

Main Results:

• Tinnitus and control brain networks showed distinct topologies across most frequency bands, with significant overlap in the gamma band.
• Differences in delta, theta, and higher beta bands were attributed to changes in both hubs and connectivity.
• Alpha band alterations were primarily driven by hub changes, while gamma band differences stemmed from connectivity modifications.

Conclusions:

• Brain network topology differs between tinnitus patients and controls, with distinct adaptive mechanisms operating across frequency bands.
• Hubs and network connectivity are differentially affected by tinnitus depending on the oscillatory band.
• These findings highlight the brain's adaptive capacity in response to auditory deafferentation, offering insights into tinnitus pathophysiology.