Conscious and unconscious processing of nonverbal predictability in Wernicke's area

The association of nonverbal predictability and brain activation was examin ed using functional magnetic resonance imaging in humans. Participants rega rded four squares displayed horizontally across a screen and counted the in cidence of a particular color. A repeating spatial sequence with varying le vels of predictability was embedded within a random color presentation. Bot h Wernicke's area and its right homolog displayed a negative correlation wi th temporal predictability, and this effect was independent of individuals' conscious awareness of the sequence. When individuals were made aware of t he underlying sequential predictability, a widespread network of cortical r egions displayed activity that correlated with the predictability. Consciou s processing of predictability resulted in a positive correlation to activi ty in right prefrontal cortex but a negative correlation in posterior parie tal cortex. These results suggest that conscious processing of predictabili ty invokes a large-scale cortical network, but independently of awareness, Wernicke's area processes predictive events in time and may not be exclusiv ely associated with language.