Getting the Cocktail Party Started: Masking Effects in Speech Perception

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Cognitive Neuroscience

Background:

• Spoken conversations often occur in noisy environments, requiring cognitive resources to process speech.
• Previous research indicated the superior temporal gyrus is involved in processing competing speech streams.
• Gaps existed in understanding brain networks specific to auditory masking and equivalent processing of target vs. competing speech.

Purpose of the Study:

• To investigate neural networks involved in attentive listening to masked speech without an explicit behavioral task.
• To determine if competing speech is processed equivalently to target speech within the auditory pathway.
• To identify neural correlates of sound onset detection in noisy auditory environments.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan young healthy adults.
• Participants listened to stories masked by sounds varying in speech similarity.
• Continuous fMRI data acquisition allowed for analysis of neural activity during auditory perception.

Main Results:

• Auditory attention and control networks were activated during masked speech perception.
• Competing speech was processed in the left hemisphere, primarily within the same pathway as target speech.
• Enhanced activation in the left mid-posterior superior temporal gyrus correlated with better performance in speech-in-noise tasks.
• Right lateralized frontal activity was observed, associated with the detection of sound onsets.

Conclusions:

• Attentive listening to masked speech engages specific auditory and control networks.
• Competing speech is processed distinctly from target speech within shared neural pathways.
• Individual differences in speech-in-noise ability are reflected in specific patterns of neural activation.