title: Human Superior Temporal Gyrus Organization of Spectrotemporal Modulation Tuning Derived from Speech Stimuli.
abstract: The human superior temporal gyrus (STG) is critical for speech perception, yet the organization of spectrotemporal processing of speech within the STG is not well understood. Here, to characterize the spatial organization of spectrotemporal processing of speech across human STG, we use high-density cortical surface field potential recordings while participants listened to natural continuous speech. While synthetic broad-band stimuli did not yield sustained activation of the STG, spectrotemporal receptive fields could be reconstructed from vigorous responses to speech stimuli. We find that the human STG displays a robust anterior-posterior spatial distribution of spectrotemporal tuning in which the posterior STG is tuned for temporally fast varying speech sounds that have relatively constant energy across the frequency axis (low spectral modulation) while the anterior STG is tuned for temporally slow varying speech sounds that have a high degree of spectral variation across the frequency axis (high spectral modulation). This work illustrates organization of spectrotemporal processing in the human STG, and illuminates processing of ethologically relevant speech signals in a region of the brain specialized for speech perception.
  
  
  CONCLUSIONS
  Considerable evidence has implicated the human superior temporal gyrus (STG) in speech processing. However, the gross organization of spectrotemporal processing of speech within the STG is not well characterized. Here we use natural speech stimuli and advanced receptive field characterization methods to show that spectrotemporal features within speech are well organized along the posterior-to-anterior axis of the human STG. These findings demonstrate robust functional organization based on spectrotemporal modulation content, and illustrate that much of the encoded information in the STG represents the physical acoustic properties of speech stimuli.
authors: University of California Berkeley and San Francisco Joint Graduate Group in Bioengineering, Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, and.
authors: Patrick W
authors: PW
authors: Hullett
authors: Center for Integrative Neuroscience, Department of Neurological Surgery, School of Medicine, University of California, San Francisco, San Francisco, California 94158.
authors: Liberty S
authors: http://orcid.org/0000-0003-0182-2500
authors: LS
authors: Hamilton
authors: Center for Integrative Neuroscience, Department of Neurological Surgery, School of Medicine, University of California, San Francisco, San Francisco, California 94158.
authors: Nima
authors: N
authors: Mesgarani
authors: University of California Berkeley and San Francisco Joint Graduate Group in Bioengineering, Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, and.
authors: Christoph E
authors: http://orcid.org/0000-0002-4571-4328
authors: CE
authors: Schreiner
authors: University of California Berkeley and San Francisco Joint Graduate Group in Bioengineering, Center for Integrative Neuroscience, Department of Neurological Surgery, School of Medicine, University of California, San Francisco, San Francisco, California 94158 changed@neurosurg.ucsf.edu.
authors: Edward F
authors: EF
authors: Chang
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D001931:Brain Mapping; D004734:Energy Metabolism / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010700:Phonetics; D013067:Speech Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*
keywords: functional organization; human STG; human superior temporal gyrus; modulation tuning; modulotopic; spectrotemporal processing