Abstract
Brain mechanisms of involuntary switching of attention: Mismatch negativity (MMN), N1, and P3a. A neurocognitive model proposing two brain mechanisms for the involuntary capture of directed attention is presented. This model is mostly based on event-related brain potential (ERP) data. The model proposes that new stimuli appearing in the acoustic environment activate a transient-detector mechanism associated with the supratemporal N1 component of the auditory ERP, triggering a "call" for directed attention. The model also proposes that subtle changes in the acoustic stream activate a second mechanism based in the process generating the Mismatch Negativity (MMN). This mechanism works on the basis of a comparison between the afferent sensory input and a neural representation of the acoustic environment developed in the echoic memory. Finally, the model proposes that the P3a component is an electrophysiological index of the actual involuntary reorientation of attention to changes in the environment.