From Phonetics to Phonology: Developmental Language Disorders and Brain Plasticity
Monday, February 13
A core challenge in speech perception is the need to account for an immense amount of acoustic and phonetic variability when decoding the underlying linguistic content. Sources of phonetic variability, such as differences among talkers, actually serve to facilitate many communicative behaviors, including learning foreign language speech sounds and recognizing voices. However, listeners with dyslexia – a neurological disorder of language that impairs the development of typical reading ability – appear to process phonetic variability in a fundamentally different way. Individuals with dyslexia exhibit a substantial impairment in voice recognition abilities that results from an inability to learn phonetic consistency. Correspondingly, experiments using fMRI adaptation reveal that the brains of individuals with dyslexia exhibit reduced sensitivity to acoustic-phonetic variability compared to individuals with typical reading abilities. Reduced cortical sensitivity to variability in dyslexia is not limited to language or auditory processes, but extends to the perception of a wide range of stimuli, revealing a broad dysfunction of rapid cortical plasticity – a neural learning mechanism that supports perceptual category learning – as a core property of the dyslexic brain. These results provide an integrative framework for understanding how general-purpose mechanisms for neural plasticity support perceptual learning for speech and language, and how dysfunction of these learning mechanisms can result in specific impairment in reading ability.
Tyler’s current research interests include developmental disorders of language and reading, human voice recognition and social auditory perception, mechanisms of plasticity in human auditory cortex, and brain bases of complex auditory processing including speech and voice perception.
For further information, please contact Joan Hanson at firstname.lastname@example.org.