Representations of auditory time: pre-attentive and attentive processing of temporal sound features

As acoustic stimuli unfold in time, the auditory system particularly relies on the processing of time-sensitive information in order to establish meaningful auditory representations. Dynamic changes of incoming information in the time range of milliseconds and seconds provide fundamental cues for the interpretation of our auditory environment as exemplified by speech and music perception. This dissertation investigates pre-attentive and attentive processing of temporal stimulus properties in the auditory domain in those time ranges. It comprises four experiments using event-related potentials methods that aim at the processing of sound duration and that of dynamic spectral changes. The results provide electrophysiological evidence supporting the assumption of distinct, mostly time-range specific mechanisms contributing to the processing and representation of time in the auditory system. Findings presented here confirm the existence of one sensory-based mechanism that is operating automatically, confined to a time range of up to about 300 ms and directly related to auditory sensory memory, representing detailed temporal structure information of acoustic stimuli. This mechanism might be crucially involved in automatic auditory segmentation processes. Aside from a general enhancement of duration and temporal structure representations during attentive processing, a second mechanisms is shown to come into play when attention is explicitly drawn on the time domain, particularly affecting durations longer than 300 ms. This mechanism for temporal processing in the longer time range is shown to be cognitively controlled and is thought to draw on higher-order cognitive modules that might be shared with other modalities.