Speech perception typically takes place within the auditory cortex as evidenced by data collected using quantitative electroencephalography (qEEG). The purpose of this study was to determine if motor responses influence speech perception. We examined P300 event-related potentials during oddball stimulus recognition tasks that either required or did not require a motor response. Based on a review of the literature, it was hypothesized that similar areas of the brain would be activated in both the motor response task and the same task without a motor response immediately following the button-push condition. Two syllables, /ba/ and /ga/, were presented to 20 native English speakers (10 females and 10 males) between the ages of 19 and 30 years. An oddball paradigm consisting of standard and deviant stimuli was presented in three trials: passive listening, mental counting, and button-push. Participants were randomly assigned an order to the trials for passive listening and mental count; however, the button-push response was completed second each time. Data from event-related potentials were recorded for each participant using qEEG and combined across participants to create grand averaged waveforms. Cortical regions of activation were identified and compared across conditions. Results showed that different cortical areas were activated when the mental counting and passive listening conditions were done before and after the motor response condition. Requiring a more complicated response than is typically used to discriminate phonemes, such as with the button push response, may alter speech perception based on the cortical regions activated as measured through source localization. Further research on latencies and amplitudes of the even-related potential (ERP) waveforms is needed to determine how speech perception changes.



College and Department




Date Submitted


Document Type




First Advisor

David L. McPherson, Chair

Second Advisor

Bonnie Brinton

Third Advisor

Kathryn Lynne Cabbage


brain mapping, electroencephalography, motor response, P300, auditory perception, event-related potentials