title: Getting the Cocktail Party Started: Masking Effects in Speech Perception.
abstract: Spoken conversations typically take place in noisy environments, and different kinds of masking sounds place differing demands on cognitive resources. Previous studies, examining the modulation of neural activity associated with the properties of competing sounds, have shown that additional speech streams engage the superior temporal gyrus. However, the absence of a condition in which target speech was heard without additional masking made it difficult to identify brain networks specific to masking and to ascertain the extent to which competing speech was processed equivalently to target speech. In this study, we scanned young healthy adults with continuous fMRI, while they listened to stories masked by sounds that differed in their similarity to speech. We show that auditory attention and control networks are activated during attentive listening to masked speech in the absence of an overt behavioral task. We demonstrate that competing speech is processed predominantly in the left hemisphere within the same pathway as target speech but is not treated equivalently within that stream and that individuals who perform better in speech in noise tasks activate the left mid-posterior superior temporal gyrus more. Finally, we identify neural responses associated with the onset of sounds in the auditory environment; activity was found within right lateralized frontal regions consistent with a phasic alerting response. Taken together, these results provide a comprehensive account of the neural processes involved in listening in noise.
authors.affiliation: University College London.
authors.forename: Samuel
authors.initials: S
authors.lastname: Evans
authors.affiliation: University College London.|University of London, Royal Holloway.
authors.forename: Carolyn
authors.initials: C
authors.lastname: McGettigan
authors.affiliation: University College London.|University of California, San Francisco.
authors.forename: Zarinah K
authors.initials: ZK
authors.lastname: Agnew
authors.affiliation: University College London.
authors.forename: Stuart
authors.initials: S
authors.lastname: Rosen
authors.affiliation: University College London.
authors.forename: Sophie K
authors.initials: SK
authors.lastname: Scott
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001303:Auditory Cortex / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D010470:Perceptual Masking / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult