title: Neural correlates of the lombard effect in primate auditory cortex.
abstract: Speaking is a sensory-motor process that involves constant self-monitoring to ensure accurate vocal production. Self-monitoring of vocal feedback allows rapid adjustment to correct perceived differences between intended and produced vocalizations. One important behavior in vocal feedback control is a compensatory increase in vocal intensity in response to noise masking during vocal production, commonly referred to as the Lombard effect. This behavior requires mechanisms for continuously monitoring auditory feedback during speaking. However, the underlying neural mechanisms are poorly understood. Here we show that when marmoset monkeys vocalize in the presence of masking noise that disrupts vocal feedback, the compensatory increase in vocal intensity is accompanied by a shift in auditory cortex activity toward neural response patterns seen during vocalizations under normal feedback condition. Furthermore, we show that neural activity in auditory cortex during a vocalization phrase predicts vocal intensity compensation in subsequent phrases. These observations demonstrate that the auditory cortex participates in self-monitoring during the Lombard effect, and may play a role in the compensation of noise masking during feedback-mediated vocal control.
authors.affiliation: Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21025, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Eliades
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Wang
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology* / Q000502:physiology*; D001931:Brain Mapping; D002144:Callithrix; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D008297:Male; D008954:Models, Biological; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009622:Noise; D010470:Perceptual Masking / Q000502:physiology; D011237:Predictive Value of Tests; D013057:Spectrum Analysis; D014828:Vocalization, Animal / Q000502:physiology*