Orofacial sensorimotor cortex (OSMcx)-orofacial primary motor cortex (MIo), primary somatosensory cortex (SIo), cortical masticatory area (CMAp)-dysfunction has been implicated in many orofacial sensorimotor disorders, including dysphagia, orofacial dystonia and dysarthria, spasmodic dysphonia, apraxia of speech, bruxism, chronic pain, and temporomandibular disorders. OSMcx displays neuroplasticity in association with acquisition of novel oral motor skills, intra-oral manipulations, and pain, and clinically targeting OSMcx has promise in treatment of orofacial disorders, such as dysphagia. The relationship between OSMcx neuroplasticity and learning of new oral skills is poorly understood, and the potential of OSMcx-targeted therapies for rehabilitation of speech, chewing, and swallowing disorders is barely explored. What roles do MIo, SIo, &CMAp independently and collectively play in control of natural feeding and trained orofacial motor tasks? How are neuroplastic changes in OSMcx orofacial motor and sensory representations related to changes in task performance? To address these questions, we will quantify neuroplasticity in OSMcx, and encoding of tongue and jaw kinematics and kinetics by recording simultaneously from MIo, SIo, &CMAp during natural feeding and learning of tongue protrusion or incisor biting tasks. We have 3 specific aims:
Aim 1 : to document the modulation of activity in neural ensembles in MIo, SIo, &CMAp during feeding, and performance of tongue protrusion or incisor-biting tasks before, during, and after long-term training to these tasks.
Aim 2 : to document simultaneously in MIo, SIo, &CMAp the encoding of jaw and tongue kinematics and kinetics in neural ensembles during feeding and during performance of tongue protrusion or incisor-biting tasks before, during, and after long-term training to these tasks.
Aim 3 : to document simultaneously in MIo, SIo, &CMAp the timing and nature of neuroplasticity associated with training in tongue protrusion or incisor biting tasks. The proposed research will provide novel insights into neuronal processes underlying OSMcx control of orofacial function and lay the groundwork for future studies of the rehabilitative potential of intensive task training and neuroplastic changes n OSMcx in recovery of orofacial function. These data will inform treatments of sensorimotor disorders that target OSMcx, such as those using stimulation or brain machine interfaces. The proposed research will leverage significant advances in neural recording, kinematic measurement, and data analysis that are being applied to studies of reach-to-grasp behaviors and, for the first time, apply them to addressing clinically significant problems in orofacial function.
This research investigates the functioning of the area of the cortex of the brain that controls movements of tongue and jaw used in chewing, swallowing, and speech. It measures the changes in this area resulting from intensive training to tongue protrusion and biting tasks. Its long term goal is to understand how the ability of the brain to change can be harnessed to improve recovery from diseases of this part of the brain that make it difficult to speak and eat.