Auditory orienting to speech and environmental sounds

Information selection is mediated by top-down processes whilst bottom-up processes enable the conscious evaluation of potentially important events that are not currently selected by focussed attention. Without a good balance between these two processes, one cannot behave adequately in many situations. Auditory event-related potentials (ERPs) allow for detailed analysis of bottom-up processes. The mismatch negativity (MMN) indicates the preattentive processing of physical differences between a frequently presented standard and a rare deviant sound. The P3a is evoked by unpredictable auditory novel events and is c…