Temporal merging into pitch with click train in the macaque auditory cortex.

Temporal integration stands as a cornerstone of auditory perception, yet its underlying neural mechanisms have remained relatively elusive. The intricate process by which discrete auditory stimuli integrate into cohesive perception is defined as 'temporal merging' in this study. We use a paradigm-the transitional click train-to probe the intricacies of temporal merging within the auditory cortex. The protocol underscores a robust change response in an adapted auditory cortex upon introducing a perceptual switch between distinct pitches. Our findings delineate four pivotal determinants that modulate this change response: train duration, inter-click interval (ICI) length, ICI contrast and train regularity. Comparative analyses between the auditory cortex and the medial geniculate body underscore a cortical origin for this temporal merging, diverging from traditional thalamic inputs. Furthermore, the clinical potential of the change response is explored, demonstrating its promise as a biomarker in anesthesia monitoring and psychiatric conditions. Collectively, this research elucidates the neuronal underpinnings of temporal integration in auditory perception, provides initial evidence for the neuronal mechanisms underlying pitch perception with click trains and introduces a potent paradigm with vast clinical implications.