Jeremy Greenlee, Dept. of Neurosurgery, University of Iowa, Iowa City, IA

Current models of speech motor control posit that comparing internally generated feedforward predictions (i.e. efference copies) to the actual auditory feedback received plays a key role in error detection and correction during ongoing speech production.  These models are amenable to testing by perturbing auditory feedback to examine the underlying neural mechanisms.  For example, frequency shifts (e.g. pitch or formant shifts) have been studied using a variety of modalities.  This presentation will report our recent study of feedback perturbation in the temporal domain (i.e. delayed auditory feedback; DAF).  By using DAF during speech production and playback tasks, we have identified modulation of high gamma responses recorded directly from higher-order auditory cortex in human neurosurgical patients.  The implications of our results will be discussed in the context of neural mechanisms of speech motor control.