Event-Related Potential Differences in the Auditory Imagery of Speech and Nonspeech

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Evan Hare¹ (evan.hare@duke.edu), Ricardo Morales Torres¹, Julia Leeman¹, Joseph Zhang¹, Pooja Kabbar¹, Kristi Van Meter¹, Tobias Overath¹; ¹Duke University

Auditory imagery, the internal experience of a sound in the absence of an external sound source, is a complex cognitive process that we use each day to relive a past event or imagine a novel sound not yet experienced. Previous research has shown that auditory imagery encodes physical properties of a stimulus, including pitch, timbre, loudness, and melody. It is also known that perceived human speech sounds are processed differently than non-speech sounds. However, it is unknown whether imagined human speech sounds are processed differently from non-speech sounds as in perception, which would have broad implications for the noninvasive detection of covert speech. To answer this question, participants were trained to associate shapes with two different types of sounds: human speech and non-speech (animal vocalizations and artificial sounds). Then, they were asked to imagine these sounds when presented with the associated shape. Electroencephalography (EEG) data were recorded while the participants both imagined and heard the sounds. The amplitude of the late positive Event-Related Potential (ERP) complex (LPC, 350-500 ms) associated with imagery was significantly smaller for speech sounds than non-speech sounds over a right-posterior region of interest. In addition, participants’ self-reported ability to control auditory imagery of speech sounds as quantified by the Bucknell Auditory Imagery Scale was significantly negatively correlated with the amplitude of the LPC for speech sounds, but this relationship did not hold for non-speech sounds. This suggests that, similarly to perception, the way in which the brain simulates speech is unique compared with other sounds.

Topic Area: PERCEPTION & ACTION: Audition