Cortical Orofacial Motor Representation Effect of Diet Consistency

• Published in: Journal of dental research Vol. 89; no. 10; pp. 1142 - 1147
• Main Authors: Avivi-Arber, L., Lee, J.-C., Sessle, B.J.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.10.2010; International Association for Dental Research; SAGE PUBLICATIONS, INC
• Subjects: Animals; Biological and medical sciences; Dentistry; Diet; Electric Stimulation - instrumentation; Electromyography; Evoked Potentials, Motor - physiology; Facial Muscles - innervation; Food; Fundamental and applied biological sciences. Psychology; Male; Mandible - innervation; Micromanipulation - instrumentation; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor Cortex - anatomy & histology; Mouth - innervation; Neck Muscles - innervation; Neural Pathways - anatomy & histology; Neuronal Plasticity - physiology; Rats; Rats, Sprague-Dawley; Reaction Time - physiology; Somatosensory Cortex - anatomy & histology; Tongue - innervation; Vertebrates: nervous system and sense organs; somatosensory; motor; orofacial; plasticity; intracortical microstimulation; Cartography; Tongue; Rat; Motor pathway; Electrical stimulus; Rodentia; Central nervous system; Electrophysiology; Mechanical properties; Representation; Feeding; Encephalon; Vertebrata; Mammalia; Diet; Animal; Motor cortex; Plasticity; Sensorimotor cortex; Electromyography
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/0022034510373767

Jaw and tongue motor alterations may occur following changes in food consistency, but whether such changes are associated with re-organization of motor representations within the facial sensorimotor cortex is unclear. We used intracortical microstimulation (ICMS) and recordings of evoked electromyographic responses to determine jaw (anterior digastric) and tongue (genioglossus) motor representations within the histologically defined face primary motor cortex (face-M1) and adjacent somatosensory cortex (face-S1) of rats fed hard (N = 6) or soft (N = 6) diet for 2 to 3 weeks. ICMS evoked jaw and tongue responses from an extensive area within the face-M1 and a smaller area within the face-S1. A significant contralateral predominance was reflected in the number and latency of ICMS-evoked jaw responses (p < 0.05). There were no significant differences between the hard- and soft-diet groups in jaw and tongue motor representations, suggesting that the rat’s ability to adapt to changes in diet consistency may not be associated with significant neuroplasticity of sensorimotor cortex motor outputs.