Interpretation of mentalistic actions and sarcastic remarks: effects of frontal and posterior lesions on mentalising.

Recent work has linked mentalising ability to ventromedial frontal brain regions, the temporal poles and the temporo-parietal junction. The present study set out to examine the performance of participants with focal frontal and posterior lesions and a matched healthy control group on mentalising tasks with different types of pragmatic materials. Four types of materials were used: control physical events, human actions, and direct and indirect sarcastic remarks. Ability to interpret these was tested by asking participants both to explain the events, actions or remarks, and then to choose the best solution from four alternatives presented. Those with frontal lesions were impaired in comprehension of each of the sets of mentalistic materials, but were intact in comprehension of the control non-mentalistic items. There was some evidence linking the generation of free responses for the mentalistic materials to lateral frontal regions; this may be mediated by executive skills. There was also evidence linking selection amongst alternative solutions to right frontal regions, particularly ventromedial areas. There was little evidence that posterior regions played any significant part, at least for the present mentalistic materials. Errors in sarcasm comprehension made by participants with frontal lesions revealed that these were not always literal in nature, suggesting two separable components in comprehension: appreciating that a meaning is not intended literally, and understanding the specific meaning in the social context.