Event related potentials changes associated with the processing of auditory valid and invalid targets as a function of previous trial validity in a Posner's paradigm.

The present study tries to analyze the neural basis of the so-called "Inter-trial Validity-Invalidity Effects" by means of Event-Related Potentials. The N1, P2, P3a and P3b components were examined. The aim is to show the sequential effects on Event-Related Potentials by analyzing the effect of previous trial condition (n-1) in the processing of current trial target (n). Event-Related Potentials results indicate that the N1 and P2 components show higher negativity in valid trials preceded by invalid trials with respect to valid trials preceded by valid trials, elicited by the so-called "Processing Negativity". Next, the P3a and P3b components show increased positivity in invalid trials preceded by valid trials compared to invalid trials preceded by invalid trials. Present results suggest that there is a dynamic updating of attentional resources and working memory, due to the influence of previous trial condition (n-1) on the current trial processing (n). This dynamic updating would be higher after trial validity changes, and it would be compatible with the Bayesian Brain Model.