Edward Chang, MD

Speech Mechanisms

A unique and defining trait of human behavior is our ability to communicate through speech. My laboratory is interested in determining the basic mechanisms that underlie speech perception and production.  While much of this processing has been localized to the peri-sylvian cortex, including Broca’s and Wernicke’s areas, the fundamental organizational principles of these neural circuits are completely unknown.

To address this, my laboratory applies a variety of experimental approaches including psychophysics, local field potential and microelectrode array recordings, electrocortical stimulation, and real-time signal processing.  These methods allow us to examine both local circuitry and global network dynamics spanning multiple cortical and sub-cortical regions with unparalleled spatial and temporal resolution in humans.

Our central goal is to provide a mechanistic account for the major properties of speech behavior in normal speakers and those with language disorders. Our ongoing research is not only deepening understanding of speech and its disorders, but also is leading directly to safer brain mapping methods to preserve language function during awake neurosurgical procedures. 

Current Projects

Speech perception
1. How do invariant cortical sensory representations give rise to categorical perception?
2. How does response selectivity of auditory cortical neurons account for high-order, complex sound processing?
3. How does the auditory cortex maintain robust speech representation in multi-speaker or noisy environmental contexts?

Speech production
1. What is the basic functional organization of the speech motor cortex and Broca’s area?
2. How are syllable sequences encoded in these brain regions to generate meaningful word forms?
3. What are the mechanisms by which sensory feedback is used to guide vocal motor control?

Lab Members

Lab Website