8. The P300 Components in a Three-Stimuli Auditory Oddball Paradigm

Abstract

The P300 Components in a Three-Stimuli Auditory Oddball Paradigm

Lynn Cameron, Philip Brust, Troy A. Smith

When the brain detects an unexpected change, it generates an electrical signal which can be measured at the scalp using electroencephalography (EEG). This P300 signal is generated in the parietal cortex approximately 300 ms after a rare stimulus is detected within a series of common stimuli. Recent research has shown the P300 has two subcomponents, the P3a and P3b, that depend on whether a rare stimulus is task oriented or not. Our research project uses a three-stimuli auditory oddball paradigm to examine these subcomponents. In this paradigm, participants hear sequences of 80 auditory tones. Within each sequence, a common tone is presented 80% of the time, a rare tone with no response required (novel) 10% of the time, and a rare target tone with response required (target) 10% of the time. We expect to replicate the robust finding that the P300 is stronger for the rare stimuli than the common stimuli. Additionally, we expect to see a stronger P3a at frontal electrodes for the novel stimuli, and a stronger P3b in parietal electrodes for the target stimuli. Future analyses of brainwave frequencies and power will further explore the differences between the three conditions. The results of this research will provide specific measures of normal brain activity that can be used to help us better understand attention, perception, decision making, and memory. This will also improve our understanding of the brain activity in individuals with mental disorders or impairments.

Keywords: auditory oddball, P300, P3a, P3b, electroencephalography (EEG), change detection