To derive meaning from natural sounds, the brain must integrate information across tens to hundreds of milliseconds. But it is unknown how different regions and hemispheres of human auditory cortex collectively integrate across multiple timescales. To answer this question, we developed a novel method to estimate integration periods and applied this method to intracranial recordings. We show that human auditory cortex integrates across time hierarchically, with three-fold longer integration periods in non-primary vs. primary regions, but no difference between hemispheres. Moreover, we show that selectivity for categories, such as speech and music, is restricted to electrodes with long integration periods. These findings suggest that short-term structure in natural sounds is analyzed by general-purpose acoustic mechanisms in primary auditory cortex, and then integrated over long timescales to form category-specific representations in non-primary regions. Our study thus reveals how the human brain constructs abstract representations of sound by integrating across multiple timescales.
bioRxiv Subject Collection: Neuroscience