Evidence for A Neural System For Learning

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How do we learn? What neural systems within the brain are responsible for human learning? Can we use electroencephalography (EEG; i.e., brain waves) to find a reliable neural marker evoked by the processing of performance feedback that is indicative of an underlying learning process? In the past 20 years, a multitude of studies have used EEG to examine the neural signals elicited by performance feedback. In particular, studies using EEG in humans have revealed two key signals evoked by performance feedback that are thought to relate to learning: (1) the feedback-related negativity (FRN) and (2) and reward positivity (RP). Theoretical accounts posit that the FRN and RP reflect the functioning of a reinforcement learning system within the human medial-frontal cortex. However, to date it is still unclear whether the FRN and RP are simply evoked by feedback or whether they are actually reflective of an underlying learning process. The proposed research seeks to answer this question and demonstrate that the FRN and RP are neural markers for a learning system within the human-medial-frontal cortex. The proposed research has three short-term objectives based on EEG methodologies. First, I will demonstrate that changes in the FRN and RP over time mirror theoretical predictions. Specifically, here we will demonstrate that changes in the FRN and RP over time resemble the learning curves seen in behavioural data. Second, I will examine if learning-related changes seen in the FRN and RP are stable and sensitive to different practice constructs that impact retention. For example, it has long been known that spacing out practice sessions (i.e., distribution of practice) results in greater learning. As such, if the FRN and RP are reflective of an underlying process these EEG components should be sensitive to distribution of practice. Third, I will determine if signals such as the FRN and RP are related to and predictive of subsequent changes in behaviour. Indeed, if the FRN and RP are reflective of a learning process then the size of these EEG components should be related to the size of behavioural modifications larger error signals should relate to larger changes in behaviour. Together, the answers of these three research objectives if supportive will demonstrate that the FRN and RP are markers for a neural learning system within the human brain. Importantly, these findings will demonstrate that we have a reliable neural marker that will allow us to gauge human learning directly instead of relying solely on indirect behavioural measures an outcome that will have a huge impact in education and industry across Canada.