Vocal communication is a vital aspect of human life. This complex behavior requires integration of the auditory feedback produced during speaking to optimize ongoing vocal production. Significant public health burden arises when vocal communication and the requisite sensorimotor integration occurring during vocalization are impaired. For example, diseases such as stuttering, aphasia, schizophrenia, and autism are felt to involve disordered sensorimotor integration. In order to develop better treatments for the millions of Americans suffering from these common diseases, it is necessary to understand the functional organization of the vocal sensorimotor brain network. Previous studies in other species suggest two parallel systems of vocal production- one involving anterior cingulate cortex (ACC) and one involving the laryngeal motor cortex (LMC). The functions of each of these areas, and the connectivity between them, are not known in humans. We will utilize complementary experimental techniques in human neurosurgery patients to overcome long-standing barriers of research progress and improve our understanding of the role of ACC and LMC in the vocal sensorimotor network. Our techniques will include functional brain imaging (MRI), high-resolution direct brain recordings, and reversible perturbation of cortical function through brain stimulation and cooling to define ACC, LMC, and auditory cortical vocalization-related physiology. We will also delineate the network connectivity between these regions. These techniques will test our hypotheses that ACC and LMC are critical to predictive coding and error detection and correction mechanisms involved in vocal control. To our knowledge, this data will be the first of its kind to directly define and test human ACC and LMC vocalization-specific responses. Such knowledge will provide mechanistic insights that cannot be obtained using other techniques and will guide development of new treatments of impaired vocal communication.
Impaired vocal communication is common and reduces quality of life for millions of Americans. Our research will provide unique insights into the structure and function of the human vocal sensorimotor network that underlies effective communication. This knowledge cannot be obtained in other ways, will provide an improved understanding of the organization of the human brain, and allow development of novel treatments for affected patients.
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