DescriptionThe traditional approach in studies of sensory coding in neurophysiology is to look for correlations between the firing properties of neurons and physical properties of stimuli. However, the current work shows that auditory responses in the auditory forebrain of awake animals in the passive hearing state was dynamically modulated by preceding acoustic experience at varying time scales: 1) Auditory responses to sequences of acoustic events were modulated by the order of events at a time scale of ten to hundreds of milliseconds. 2) Once a stimulus has been presented at a certain inter-stimulus interval (ISI) for several trials, a few seconds delay in the ISI changed the amplitude of the response. 3) Auditory responses were enhanced when a sound was presented along with context sounds from a different category, reflecting categorical prediction of upcoming sounds derived from recent acoustic history over a time scale from seconds to minutes. 4) Familiarity of contextual sounds, lasting for minutes to hours, changed the strength of responses of other sounds and enhanced the responses to novel sounds in a familiar acoustic context. These results may shed light on three mechanisms that are essential for auditory object perception: 1) temporal integration of acoustic sequences, 2) categorical processing of salient stimuli with a continuum of features, e.g. vocalizations, and 3) segregation of auditory objects from natural acoustic scenes.