A Bayesian Account of Vocal Adaptation to Pitch-Shifted Auditory Feedback

• Published in: PloS one Vol. 12; no. 1; p. e0169795
• Main Authors: Hahnloser, Richard H R, Narula, Gagan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.01.2017; Public Library of Science (PLoS)
• Subjects: Acuity; Adaptation; Adaptation, Physiological; Adaptive systems; Algorithms; Analysis; Animals; Auditory stimuli; Bayes Theorem; Bayesian analysis; Biology and Life Sciences; Birds; Brain; Compensation; Experiments; Feedback; Feedback loops; Feedback loops (Systems theory); Feedback, Sensory - physiology; Frequency; Hearing impairment; Hearing loss; Humans; Methods; Models, Theoretical; Motor systems; Neurosciences; Observations; Optimization; Pitch discrimination; Pitch Perception - physiology; Psychophysics; Social Sciences; Songbirds - physiology; Stochastic Processes; Variability; Vocal registers; Vocalization, Animal - physiology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0169795

Motor systems are highly adaptive. Both birds and humans compensate for synthetically induced shifts in the pitch (fundamental frequency) of auditory feedback stemming from their vocalizations. Pitch-shift compensation is partial in the sense that large shifts lead to smaller relative compensatory adjustments of vocal pitch than small shifts. Also, compensation is larger in subjects with high motor variability. To formulate a mechanistic description of these findings, we adapt a Bayesian model of error relevance. We assume that vocal-auditory feedback loops in the brain cope optimally with known sensory and motor variability. Based on measurements of motor variability, optimal compensatory responses in our model provide accurate fits to published experimental data. Optimal compensation correctly predicts sensory acuity, which has been estimated in psychophysical experiments as just-noticeable pitch differences. Our model extends the utility of Bayesian approaches to adaptive vocal behaviors.