Unexpectedness of both observed errors and successes activates the dorsomedial prefrontal and rostral cingulate cortex in humans
It has been sometimes said that the ability to predict what is going to happen next is the primary task that the human brain needs to accomplish (e.g., perhaps the reason that ability to form memories of past events ever developed was solely due to the need to be able to predict the future). Indeed, when observing others, there typically are few surprises, and unexpected acts robustly catch one’s attention to figure out what is taking place. Activation of dorsomedial prefrontal cortical areas together with rostral cingulate cortex has been associated in previous studies with both detection of errors (e.g., when observing someone fail on a task) and observation of surprising events. Whether the responses seen in these areas are more due to unexpectedness or erroneousness of observed actions has, however, remained as an unresolved issue.
In their recent study, Dr. Anne-Marike Schiffer et al. (2013) studied whether responses in the aforementioned brain areas are more due to unexpectedness or erroneousness of observed actions. They presented video clips, shot from a first-person perspective, of an actress making sailing, fishing, and climbing knots. The videos were edited so that both unexpected failures and unexpected successes were observable, as also validated in a separate behavioral experiment carried out in the volunteers who all were sufficiently skilled in making the knots themselves. The movie clips were then shown to the volunteers during functional magnetic resonance imaging. The results indicated an area encompassing medial prefrontal cortex and rostral cingulate cortex that responded to both correct and erroneous knot-tying actions that were unexpected.
These very important and interesting results suggest that, at least to some extent, previously observed error-related responses in dorsomedial prefrontal cortex and rostral cingulate gyrus could have been due to unexpectedness of the errors. Based on their findings, the authors further bring up the interesting possibility that an unexpectedness signal in the dorsal rostral cingulate gyrus could serve the purpose of adjusting internal models that help predict flow of actions. Overall, this study is a very nice demonstration of how behavioral and neuroimaging experiments can be combined to advance our understanding of the neural basis of cognitive functions.
Reference: Schiffer A-M, Krause KH, Schubotz RI. Surprisingly correct: unexpectedness of observed actions activates the medial prefrontal cortex. Human Brain Mapping (2013) online e-publication ahead of print. http://dx.doi.org/10.1002/hbm.22277