Binaural hearing provides a perceptual advantage in detecting brief gaps in sound, yet the neural mechanisms underlying this benefit remain poorly understood. This study examined the cortical dynamics and lateralization associated with the binaural advantage and ear advantage in auditory gap detection using event-related potentials (ERPs) and effective connectivity analysis. Sixteen normal-hearing adults were presented with monaural (left and right ear) and binaural broadband pink noise stimuli containing silent gaps of varying durations, while EEG was recorded. We analyzed the Mismatch Negativity (MMN) to assess auditory gap detection. Source-localized activity and Granger causality were analyzed across ten functionally defined scouts to evaluate cortical dynamics and effective connectivity underlying ear asymmetry and binaural advantage. Results revealed significantly larger and earlier MMN responses in the binaural condition compared to monaural presentations, with stronger activation in contralateral temporal clusters for monaural conditions. Source-localized activity and effective connectivity exploratory analyses showed an overall enhanced activation for binaural stimulation for the standard stimuli. However, despite the stronger MMN observed in the binaural difference wave, source activity revealed a pattern of binaural suppression. Connectivity analyses further showed pronounced variations originating from the left auditory cortex and temporal gyri depending on listening condition, whereas connectivity involving the right auditory cortex varied as a function of gap duration. Together, these findings suggest that the binaural advantage relies on more efficient, facilitated mechanisms, while monaural stimulation requires increased cortical activity and connectivity to support temporal discrimination.
