Speech perception is the process by which listeners hear and interpret the sounds of language. It is defined by the unique mapping of a highly variable and complex acoustic signal to a phonetic representation. A convergence of studies has implicated the human posterior superior temporal cortex for the specialized processing of speech sounds. Although localized, the basic neural mechanisms by which linguistic information is extracted are entirely unclear. We propose an innovative methodological approach using customized intracranial high-density electrode arrays to record detailed neural activity directly from the posterior temporal cortex in awake, behaving subjects undergoing clinical evaluation for epilepsy surgery. This method offers the highest possible spatial and temporal resolution, thereby overcoming many limitations of non-invasive imaging approaches. This research is positioned at a critical interface between the fields of auditory neuroscience and linguistics. Our previous results demonstrate that cortical representation of speech sounds manifest important non-linearities that correspond to perceptual boundaries over acoustic parameters (Chang et al, Nature Neuroscience 2010). Building on these findings, we propose experiments to determine: 1) the functional organization of the posterior temporal gyrus for acoustic and phonetic features, 2) the distributed, population-level encoding of emergent phonetic representation, and 3) the correlates of "robust" speech representation in the context of a multi-speaker listening environment. The results of these proposed experiments will have significant impact on the field of neurolinguistics and broader research on sensory perception and cognition.
Alterations in the cortical mechanisms supporting speech perception underlie the pathogenesis of an increasing number of acquired and developmental language disabilities, including aphasia, language learning delay, autism, and dyslexia. Revealing mechanisms by which the brain encodes speech sounds bears tremendous implications for our understanding of these disorders, and more importantly, will guide strategies for their remediation.
|Simonyan, Kristina; Ackermann, Hermann; Chang, Edward F et al. (2016) New Developments in Understanding the Complexity of Human Speech Production. J Neurosci 36:11440-11448|
|Leonard, Matthew K; Cai, Ruofan; Babiak, Miranda C et al. (2016) The peri-Sylvian cortical network underlying single word repetition revealed by electrocortical stimulation and direct neural recordings. Brain Lang :|
|Moses, David A; Mesgarani, Nima; Leonard, Matthew K et al. (2016) Neural speech recognition: continuous phoneme decoding using spatiotemporal representations of human cortical activity. J Neural Eng 13:056004|
|Bouchard, Kristofer E; Conant, David F; Anumanchipalli, Gopala K et al. (2016) High-Resolution, Non-Invasive Imaging of Upper Vocal Tract Articulators Compatible with Human Brain Recordings. PLoS One 11:e0151327|
|Muller, Leah; Hamilton, Liberty S; Edwards, Erik et al. (2016) Spatial resolution dependence on spectral frequency in human speech cortex electrocorticography. J Neural Eng 13:056013|
|Fonken, Yvonne M; Rieger, Jochem W; Tzvi, Elinor et al. (2016) Frontal and motor cortex contributions to response inhibition: evidence from electrocorticography. J Neurophysiol 115:2224-36|
|Hullett, Patrick W; Hamilton, Liberty S; Mesgarani, Nima et al. (2016) Human Superior Temporal Gyrus Organization of Spectrotemporal Modulation Tuning Derived from Speech Stimuli. J Neurosci 36:2014-26|
|Dichter, Benjamin K; Bouchard, Kristofer E; Chang, Edward F (2016) Dynamic Structure of Neural Variability in the Cortical Representation of Speech Sounds. J Neurosci 36:7453-63|
|Cheung, Connie; Hamiton, Liberty S; Johnson, Keith et al. (2016) The auditory representation of speech sounds in human motor cortex. Elife 5:|
|Breshears, Jonathan D; Molinaro, Annette M; Chang, Edward F (2015) A probabilistic map of the human ventral sensorimotor cortex using electrical stimulation. J Neurosurg 123:340-9|
Showing the most recent 10 out of 25 publications