S13_1. Decoding and Predicting Intentions from Patterns of Human Brain Activity: Lessons for the Architecture of Prefrontal Cortex

The neural encoding of intentions plays a special role in the human brain. Because various cognitive subprocesses are orchestrated with the purpose of realizing intentions, the neural representation of an intention should be the best predictor of current and future brain activity. For this reason our group has conducted a number of studies that attempt to identify the neural code with which intentions are stored in the human brain. We applied multivariate pattern classifiers to brain signals recorded while subjects were holding certain intentions in mind 1-9 . The aim was to identify brain regions where subcomponents of intentions would be decodable. Following this approach we assessed where it is possible to decode free-chosen versus cued intentions, where intentions can be decoded across delays (“prospective memory”), how intentions are reimplemented after delays and how complex intentions are coded based on simple constituent elements (“compositionality”). Our findings provide a complementary view to existing ideas on prefrontal coding. We neither found evidence for equipotentiality where a set of regions participates in coding a large number intentions, without much differentiation; nor did we find evidence for a gradient of increasing complexity running from posterior to anterior PFC. Instead, our results suggest a compositional view of PFC where different aspects of intentions (cues, tasks, timing, conditions, etc.) are coded in different subregions. In another line of research we tried to predict which intention a person would choose to pursue even before subjects believed they were consciously making up their mind 1,8 . Our results show that the specific outcome of free choices between different plans can be interpreted from brain activity, not only after a decision has been made, but even several seconds before it is made. This suggests that a causal chain of events can occur outside subjective awareness even before a subject makes up his/her mind.