Evidence for A Neural System For Learning

我们如何学习？大脑中哪些神经系统负责人类的学习？我们是否可以使用脑电图（EEG，即脑电波）找到一个可靠的神经标记，由表现反馈的处理引起，表明一个潜在的学习过程？在过去的20年里，大量的研究使用脑电图来检测由行为反馈引起的神经信号。特别是，在人类中使用脑电图的研究已经揭示了被认为与学习有关的表现反馈所诱发的两个关键信号：(1)反馈相关的负性（FRN）和(2)奖励正性（RP）。理论上，FRN和RP反映了人类中额叶皮层内强化学习系统的功能。然而，到目前为止还不清楚FRN和RP是否仅仅是由反馈引起的，还是它们实际上反映了一个潜在的学习过程。提出的研究试图回答这个问题，并证明FRN和RP是人类内侧额叶皮层中学习系统的神经标记。

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.