Neural indices of spoken word processing in background multi-talker babble.

Area of Science:

• Neuroscience
• Auditory Perception
• Cognitive Psychology

Background:

• Understanding how background noise affects speech processing is crucial for real-world auditory comprehension.
• Cortical event-related potentials (ERPs), particularly the N400, offer insights into semantic processing.
• The N400 component is sensitive to semantic relatedness and can be modulated by listening conditions.

Purpose of the Study:

• To investigate the effect of multi-talker babble on cortical event-related potentials (ERPs), specifically the N400 component.
• To examine how a degraded auditory environment influences neural responses during a spoken semantic priming task.

Main Methods:

• Participants (n=12 young adults, normal hearing) underwent a spoken semantic priming task in quiet and in multi-talker babble.
• Cortical event-related potentials (ERPs) to word triplets were analyzed using temporo-spatial principal component analysis.
• Neural activity was assessed for the first (S1) and second (S2) words without an overt behavioral response.

Main Results:

• Background babble did not significantly alter the N400 in posterior brain regions.
• Babble increased neural processing negativity in anterior and central regions, particularly for related S2 words.
• This differential processing negativity in babble was observed for S2 but not S1.

Conclusions:

• Speech processing in a degraded auditory environment modulates neural activity in anterior and central scalp regions.
• These findings suggest that background babble impacts neural mechanisms underlying auditory working memory, attention, and semantic processing.
• The N400 component's sensitivity to semantic processing is maintained, but additional neural resources are engaged in noisy conditions.