Selective modulation of interhemispheric connectivity by transcranial alternating current stimulation influences...

Area of Science:

• Neuroscience
• Auditory Perception
• Brain Connectivity

Background:

• Neural oscillations, particularly in the gamma (γ) frequency band, are theorized to mediate perceptual integration.
• Interregional synchronization of neural activity is a proposed mechanism for integrating sensory information.
• Previous research suggested that modulating interhemispheric oscillatory synchrony affects binaural integration.

Purpose of the Study:

• To directly link neural oscillatory synchrony, effective brain connectivity, and binaural integration.
• To investigate the causal role of γ-band synchronization between auditory cortices in binaural hearing.
• To determine how experimentally manipulated oscillatory synchrony affects brain network dynamics and perceptual performance.

Main Methods:

• Utilized bihemispheric γ-transcranial alternating current stimulation (TACS) with varying interhemispheric phase lags to manipulate oscillatory synchrony.
• Employed functional magnetic resonance imaging (fMRI) to assess changes in effective brain connectivity.
• Measured binaural integration using a dichotic listening task.

Main Results:

• TACS decreased intrahemispheric connectivity within auditory cortices.
• Antiphase TACS (180° interhemispheric phase lag) modulated connectivity between the left and right auditory cortices.
• Changes in both intra- and interhemispheric connectivity induced by TACS correlated with alterations in perceptual integration.

Conclusions:

• γ-band synchronization between the two auditory cortices plays a functional role in binaural integration.
• The findings support the hypothesis that interregional oscillatory synchrony is a key mechanism for perceptual integration.
• This study provides direct evidence for the involvement of specific brain network dynamics in auditory scene analysis.