My work pictured by AI – Chantal Oderbolz

What is this work about? The speech signal carries hierarchically organized acoustic and linguistic information. Recent research suggests that the brain uses brain waves, called cortical oscillations, to process this information. Especially oscillations in the theta frequency range (4-8 Hz) have been found to be important: Theta oscillations process acoustic energy in the speech signal associated with the timing of syllables. However, there is also slower information in the speech signal that corresponds to stress and intonation patterns and are part of the prosody – the rhythm and melody – of a language.

To better understand how the brain processes these different levels at the same time, we conducted an experiment with 30 participants who listened to German sentences with manipulated stress and intonation patterns. We found that the brain is able to simultaneously process the syllable, stress and intonation patterns of speech. However, changes in stress patterns disrupted the brain’s ability to track syllables with theta oscillations. Conversely, the brain was able to compensate for changes in intonation patterns by using linguistic knowledge. Additionally, we found that individuals varied in their ability to process the prosodic structure of the speech signal, with some participants better able to compensate for acoustic changes than others. Overall, our results support the idea that the brain uses a hierarchical organization of cortical oscillations to process the speech signal.

The first word that came to mind when seeing the AI-generated picture? Nostalgia.