title: Plasticity in primary auditory cortex of monkeys with altered vocal production.
abstract: Response properties of primary auditory cortical neurons in the adult common marmoset monkey (Callithrix jacchus) were modified by extensive exposure to altered vocalizations that were self-generated and rehearsed frequently. A laryngeal apparatus modification procedure permanently lowered the frequency content of the native twitter call, a complex communication vocalization consisting of a series of frequency modulation (FM) sweeps. Monkeys vocalized shortly after this procedure and maintained voicing efforts until physiological evaluation 5-15 months later. The altered twitter calls improved over time, with FM sweeps approaching but never reaching the normal spectral range. Neurons with characteristic frequencies <4.3 kHz that had been weakly activated by native twitter calls were recruited to encode self-uttered altered twitter vocalizations. These neurons showed a decrease in response magnitude and an increase in temporal dispersion of response timing to twitter call and parametric FM stimuli but a normal response profile to pure tone stimuli. Tonotopic maps in voice-modified monkeys were not distorted. These findings suggest a previously unrecognized form of cortical plasticity that is specific to higher-order processes involved in the discrimination of more complex sounds, such as species-specific vocalizations.
authors.affiliation: Coleman Memorial Laboratory and W. M. Keck Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California 94143-0342, USA. scheung@ohns.ucsf.edu
authors.forename: Steven W
authors.initials: SW
authors.lastname: Cheung
authors.forename: Srikantan S
authors.initials: SS
authors.lastname: Nagarajan
authors.forename: Christoph E
authors.initials: CE
authors.lastname: Schreiner
authors.forename: Purvis H
authors.initials: PH
authors.lastname: Bedenbaugh
authors.forename: Andrew
authors.initials: A
authors.lastname: Wong
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D002144:Callithrix; D007858:Learning / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D014828:Vocalization, Animal / Q000502:physiology*