Mapping of Auditory Cortical Functions Using Electrocorticography

Abstract

Communication is a dynamic process through which we translate our inner thoughts in such a way that they can be shared with another person. This complex neurological phenomenon is a key predictor of our productivity and health. When our ability to communicate is compromised, our quality of life suffers. Although numerous methods to investigate the neuroscientific underpinnings of human language exist, our understanding of this process remains incomplete. Improving our understanding of where, when, and how auditory cortical activity occurs can enhance diagnostic techniques and improve treatment methods for neurological conditions that can impact auditory processing, such as epilepsy, or brain tumors. Recently, electrocorticography (ECoG) has come forward as a promising neuromonitoring technique for evaluating auditory cortical functions. ECoG has the ability to investigate cortical activity at a sub-centimeter scale with millisecond time resolution. This can provide new insights into the spatiotemporal activation patterns elicited when human subjects hear sounds and understand language. In this dissertation, I use ECoG recordings to investigate the spatiotemporal dynamics of cortical activity during receptive auditory tasks. I demonstrate that ECoG is an excellent technique for localizing functional cortical activity and that this technique has the capacity to supplement and eventually replace current localization techniques. Beyond localizing the areas of cortex responsible for processing receptive auditory information, I show that cortical activity progresses in a characteristic caudal-to-rostral direction along the length of the superior temporal gyrus when subjects are presented with speech stimuli, but not in the absence of speech components. Together, these results advance our understanding of the human auditory cortex and open up new avenues for developing medical diagnostic techniques and improved treatment methods for auditory cortical dysfunction