title: Distinct neural systems recruited when speech production is modulated by different masking sounds.
abstract: When talkers speak in masking sounds, their speech undergoes a variety of acoustic and phonetic changes. These changes are known collectively as the Lombard effect. Most behavioural research and neuroimaging research in this area has concentrated on the effect of energetic maskers such as white noise on Lombard speech. Previous fMRI studies have argued that neural responses to speaking in noise are driven by the quality of auditory feedback-that is, the audibility of the speaker's voice over the masker. However, we also frequently produce speech in the presence of informational maskers such as another talker. Here, speakers read sentences over a range of maskers varying in their informational and energetic content: speech, rotated speech, speech modulated noise, and white noise. Subjects also spoke in quiet and listened to the maskers without speaking. When subjects spoke in masking sounds, their vocal intensity increased in line with the energetic content of the masker. However, the opposite pattern was found neurally. In the superior temporal gyrus, activation was most strongly associated with increases in informational, rather than energetic, masking. This suggests that the neural activations associated with speaking in noise are more complex than a simple feedback response.
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
authors.forename: Sophie
authors.initials: S
authors.lastname: Meekings
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
authors.forename: Samuel
authors.initials: S
authors.lastname: Evans
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
authors.forename: Nadine
authors.initials: N
authors.lastname: Lavan
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
authors.forename: Dana
authors.initials: D
authors.lastname: Boebinger
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
authors.forename: Katya
authors.initials: K
authors.lastname: Krieger-Redwood
authors.affiliation: University of the Basque Country, Facultad de Letras, Universidad del País Vasco/EHU, Paseo de la Universidad 5, Vitoria, Alava 01006, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: Cooke
authors.affiliation: Psychology and Language Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Sophie K
authors.initials: SK
authors.lastname: Scott
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D009622:Noise; D010470:Perceptual Masking / Q000502:physiology*; D010700:Phonetics; D013060:Speech / Q000502:physiology*; D013068:Speech Production Measurement