Language comprehension interrupted: both language errors and word degradation activate Broca's area

The proposal of a general conflict resolution mechanism in lIFG was investigated further in relation to language errors. In an fMRI study participants read sentences containing syntactic and plausibility violations. Furthermore, they were presented with sentences that were difficult to comprehend, due to degradation of the bottom-up signal (i.e., the visual form) of the language. We were interested whether comprehension difficulties caused by degradation would activate cognitive control mechanisms in the same manner as other language violations. To localize cognitive control processes participants performed a Stroop task. Both the violations and the visual degradation condition elicited co-localized lIFG activation with the Stroop conflict. These results indicate that lIFG implements control adjustments to resolve situations in which extra attention is needed more generally. Next to biasing attention to resolve representational conflicts arising from different types of errors, lIFG may also adjust control to compensate for a temporary lack of bottom-up information.