Liberty Hamilton, Ph.D.

Assistant Professor, Department of Communication Sciences and Disorders

University of Texas at Austin

Research Summary

Human speech perception involves transforming a highly variable acoustic signal into a meaningful linguistic representation (phonemes, words, and meaning). People can parse speech sounds with high fidelity despite wide variations in this signal related to speaker identity, speaker rate, phonetic context, and levels of background noise. How the brain is able to do this is still poorly understood. Furthermore, it is unknown how speech processing in the brain changes during development, as children learn to speak and understand language. Dr. Liberty Hamilton, Assistant Professor in the Department of Communication Sciences and Disorders and the Department of Neurology at UT Austin, conducts research examining how brain networks process speech sounds, and how neural representations of speech and other environmental sounds change during development. This research will help uncover how the healthy human brain processes speech sounds, but will also provide insight into potential treatments for those with communication disorders or other language-related disabilities.

 Dr. Hamilton’s research is performed in a unique clinical setting, in collaboration with clinicians at Dell Children’s Comprehensive Epilepsy Center. Her lab works with patients with epilepsy who experience seizures that cannot be effectively controlled with medication. These patients undergo a surgery in which grids of electrodes are placed on the surface of their brain in order to localize the source of epileptic activity by recording electrical activity directly from the brain surface, a method called electrocorticography (ECoG). After seizures are localized to a particular brain area, that brain area is resected in a surgery. This type of surgery is highly effective in reducing or eliminating seizure activity. In temporal lobe epilepsy, the areas involved in seizure activity may be near language-related areas, so it is important for clinicians to map out these areas to determine their functioning so that language function is minimally affected. Our research, while separate from this clinical mapping, also provides a window into language function and localization in these patients. During a patient’s stay in the hospital, they may volunteer to participate in our research, which involves listening to words, phrases, sentences, or stories while we record their brain activity. We use this to learn how speech is processed in the brain, and how this changes depending on the patient’s age. We hope that our findings will provide insight into brain-based treatments for communication disorders including aphasia, delayed language learning, and dyslexia.

 Expertise

Dr. Hamilton has expertise in cognitive and systems neuroscience, with a special emphasis on auditory cortical physiology. She has experience with the acquisition and analysis of in vivo electrophysiological recordings of the auditory system, with a current focus on electrocorticography, but previous experience in multi-unit electrophysiology. She also has previous experience with structural and functional MRI analysis.

 Collaborative interests

Dr. Hamilton is interested in collaborations with researchers investigating auditory response properties through development in human and animal models.  She is also interested in collaborating with researchers who apply non-invasive methods to investigate brain structure and function, especially during development.

 

For more information, see https://csd.utexas.edu/research/hamilton-lab