The Role of the N2b Event-Related Potential Component in Concussion

Sophie Krokhine
Honours Chemical Biology, Class of 2024, McMaster University
krokhins@mcmaster.ca

Electroencephalography (EEG) has long been used to measure brain activity. An event-related potential (ERP) measures an EEG response to a specific stimulus, usually over several hundred milliseconds¹. There are several ERP components, named based on their polarity and latency, that provide insight into human perceptual processes and impairments in certain conditions, such as concussion. Along with a team at McMaster’s ARiEAL Research Centre, I conducted a scoping review on an ERP component called the N2b and its usage in identifying executive functioning deficits post-concussion. Specifically, the N2b is thought to reflect selective attention, conflict monitoring (the management of conflicting signals from stimuli), and response inhibition. The studies reviewed used various paradigms to measure the N2b, the most common of which were the oddball paradigm (in which subjects were asked to respond to a deviant or novel stimulus in the midst of background stimuli) and the Flanker task (in which subjects had to respond to the direction or properties of a central stimulus which was surrounded by opposite flanker stimuli). They found the N2b to be increased, decreased or unaffected in people with a history of concussion; there was no main result. This was likely due to the variability in paradigms and the way the N2b was classified and labelled. There were also inconsistencies in the type and severity of head injuries reported, which could drive some of the inconclusive results. Future research will need greater standardization of patient demographics and head-injury characteristics, and we have proposed splitting the N2b into several sub-components to account for the different responses across paradigms.

1. Krokhine, S., Ewers, N., Mangold, K., Boshra, R., Lin, C. and Connolly, J., 2020. N2b Reflects the Cognitive Changes in Executive Functioning After Concussion: A Scoping Review. Frontiers in Human Neuroscience, 14.