title: Human brainstem plasticity: the interaction of stimulus probability and auditory learning.
abstract: Two forms of brainstem plasticity are known to occur: an immediate stimulus probability-based and learning-dependent plasticity. Whether these kinds of plasticity interact is unknown. We examined this question in a training experiment involving three phases: (1) an initial baseline measurement, (2) a 9-session training paradigm, and (3) a retest measurement. At the outset of the experiment, auditory brainstem responses (ABR) were recorded to two unfamiliar pitch patterns presented in an oddball paradigm. Then half the participants underwent sound-to-meaning training where they learned to match these pitch patterns to novel words, with the remaining participants serving as controls who received no auditory training. Nine days after the baseline measurement, the pitch patterns were re-presented to all participants using the same oddball paradigm. Analysis of the baseline recordings revealed an effect of probability: when a sound was presented infrequently, the pitch contour was represented less accurately in the ABR than when it was presented frequently. After training, pitch tracking was more accurate for infrequent sounds, particularly for the pitch pattern that was encoded more poorly pre-training. However, the control group was stable over the same interval. Our results provide evidence that probability-based and learning-dependent plasticity interact in the brainstem.
authors.affiliation: Auditory Neuroscience Laboratory, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, USA; Department of Communication Sciences & Disorders, School of Communication, Northwestern University, Evanston, IL 60208, USA. Electronic address: erika.skoe@uconn.edu.
authors.forename: Erika
authors.initials: E
authors.lastname: Skoe
authors.affiliation: Department of Communication Sciences and Disorders, Center for Perceptual Systems, Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA. Electronic address: bchandra@austin.utexas.edu.
authors.forename: Bharath
authors.initials: B
authors.lastname: Chandrasekaran
authors.affiliation: Auditory Neuroscience Laboratory, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, USA; Department of Communication Sciences & Disorders, School of Communication, Northwestern University, Evanston, IL 60208, USA. Electronic address: emilyspitzer2013@u.northwestern.edu.
authors.forename: Emily R
authors.initials: ER
authors.lastname: Spitzer
authors.affiliation: Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Hong Kong Special Administrative Region; Department of Communication Sciences & Disorders, School of Communication, Northwestern University, Evanston, IL 60208, USA; Department of Neurobiology & Physiology, Northwestern University. Electronic address: p.wong@cuhk.edu.hk.
authors.forename: Patrick C M
authors.initials: PC
authors.lastname: Wong
authors.affiliation: Auditory Neuroscience Laboratory, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, USA; Department of Communication Sciences & Disorders, School of Communication, Northwestern University, Evanston, IL 60208, USA; Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Otolaryngology, Northwestern University. Electronic address: nkraus@northwestern.edu.
authors.forename: Nina
authors.initials: N
authors.lastname: Kraus
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001933:Brain Stem / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D010898:Pitch Perception / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
keywords: Auditory learning; Brainstem; Neuroplasticity