title: High-gamma band fronto-temporal coherence as a measure of functional connectivity in speech motor control.
abstract: The neural basis of human speech is unclear. Intracranial electrophysiological recordings have revealed that high-gamma band oscillations (70-150Hz) are observed in the frontal lobe during speech production and in the temporal lobe during speech perception. Here, we tested the hypothesis that the frontal and temporal brain regions had high-gamma coherence during speech. We recorded electrocorticography (ECoG) from the frontal and temporal cortices of five humans who underwent surgery for medically intractable epilepsy, and studied coherence between the frontal and temporal cortex during vocalization and playback of vocalization. We report two novel results. First, we observed high-gamma band as well as theta (4-8Hz) coherence between frontal and temporal lobes. Second, both high-gamma and theta coherence were stronger when subjects were actively vocalizing as compared to playback of the same vocalizations. These findings provide evidence that coupling between sensory-motor networks measured by high-gamma coherence plays a key role in feedback-based monitoring and control of vocal output for human vocalization.
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, United States.
authors.forename: J
authors.initials: J
authors.lastname: Kingyon
authors.affiliation: Department of Neurosurgery, University of Iowa, Iowa City, IA, United States; Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC, United States.
authors.forename: R
authors.initials: R
authors.lastname: Behroozmand
authors.affiliation: Department of Neurosurgery, University of Iowa, Iowa City, IA, United States.
authors.forename: R
authors.initials: R
authors.lastname: Kelley
authors.affiliation: Department of Neurosurgery, University of Iowa, Iowa City, IA, United States.
authors.forename: H
authors.initials: H
authors.lastname: Oya
authors.affiliation: Department of Neurosurgery, University of Iowa, Iowa City, IA, United States.
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, United States; Aging Mind and Brain Initiative, Carver College of Medicine, University of Iowa, Iowa City, IA, United States. Electronic address: nandakumar-narayanan@uiowa.edu.
authors.forename: N S
authors.initials: NS
authors.lastname: Narayanan
authors.affiliation: Department of Neurosurgery, University of Iowa, Iowa City, IA, United States. Electronic address: jeremy-greenlee@uiowa.edu.
authors.forename: J D W
authors.initials: JD
authors.lastname: Greenlee
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001931:Brain Mapping; D004566:Electrodes; D004569:Electroencephalography; D005260:Female; D005583:Fourier Analysis; D005625:Frontal Lobe / Q000502:physiology*; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013060:Speech / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D013702:Temporal Lobe; D055815:Young Adult
keywords: ECoG; LFP; auditory cortex; efference copy; premotor cortex; speech