ERP Markers of Auditory Go/NoGo Processing

The Sequential Processing Schema is a data-driven model that uses event-related potential (ERP) components to chart the important psychophysiological processes activated when completing auditory equiprobable Go/NoGo tasks. This model is useful for measuring experimental effects on basic cognitive processes and provides a valuable framework to synthesise and test ERP component theories. Determining the cognitive and behavioural correlates of ERP components is critical for understanding their functional significance and utility in psychology. Additional research is also needed to refine the conceptualisation of the ERP components and cognitive processing requirements in equiprobable Go/NoGo tasks, which are commonly used in psychophysiological research. To do that, robust data-driven methods such as temporal Principal Components Analysis (PCA) are needed for effective ERP component quantification and analyses of the Go/NoGo ERP component ‘processing’ series. This doctoral thesis aimed to clarify ERP component functionality and refine our understanding of equiprobable Go/NoGo tasks by developing the Sequential Processing Schema and exploring how ERP/PCA components relate to cognitive and behavioural processing under different Go/NoGo task conditions. Study 1 compared the ERP component processing series associated with auditory equiprobable and oddball variants of the Go/NoGo task. The manipulation of probability and the relevant modulation of the ERP component series reflected a shift in particular cognitive demands or task requirements, which promoted the conceptual development of component functionality and the generalisability of the Schema. The results of Study 1 questioned the identity of a core ERP component (i.e., Processing Negativity) previously linked to auditory Go/NoGo processing; this was pursued in detail in Study 2, which aimed to clarify the ERP components associated with early information processing in auditory equiprobable and ‘frequent Go’ variants of the Go/NoGo task. Stimulus probability differences (this time the inverse of Study 1) were again used to elucidate component functionality and provide insight into the cognitive task demands. Study 3 and 4 explored ERP component functionality by examining Go stimulus- and response-locked ERP averaging effects, and the link between the equiprobable NoGo P3a and motor response inhibition. Studies 1–4 provided insight into the sequential processing requirements in auditory equiprobable Go/NoGo tasks, and the associated ERP/PCA components, promoting the development of common ERP components as indices of cognitive processes. These outcomes clarified the utility of the equiprobable Go/NoGo task, and highlight important similarities and differences between Go/NoGo and oddball processing, encouraging ERP theory development and integration between those common research paradigms. An update to the Schema was proposed to accommodate the ERP findings and reflect the refined interpretation of equiprobable Go/NoGo processing developed in this thesis, including a shift in the conceptualisation of the sensory processing and inhibitory requirements in the equiprobable task. This was considered to improve the conceptual framework of the Schema and its utility for charting the cognitive and behavioural processing in different task conditions. The outcomes also provide novel insight into how healthy young adults process information and encourage further studies of sequential processing to help delineate abnormalities in cognitive processing related to different psychopathologie