title: Carbohydrate in the mouth enhances activation of brain circuitry involved in motor performance and sensory perception.
abstract: The presence of carbohydrate in the human mouth has been associated with the facilitation of motor output and improvements in physical performance. Oral receptors have been identified as a potential mode of afferent transduction for this novel form of nutrient signalling that is distinct from taste. In the current study oral exposure to carbohydrate was combined with a motor task in a neuroimaging environment to identify areas of the brain involved in this phenomenon. A mouth-rinsing protocol was conducted whilst carbohydrate (CHO) and taste-matched placebo (PLA) solutions were delivered and recovered from the mouths of 10 healthy volunteers within a double-blind, counterbalanced design. This protocol eliminates post-oral factors and controls for the perceptual qualities of solutions. Functional magnetic resonance imaging of the brain was used to identify cortical areas responsive to oral carbohydrate during rest and activity phases of a hand-grip motor task. Mean blood-oxygen-level dependent signal change experienced in the contralateral primary sensorimotor cortex was larger for CHO compared with PLA during the motor task when contrasted with a control condition. Areas of activation associated with CHO exclusively were observed over the primary taste cortex and regions involved in visual perception. Regions in the limbic system associated with reward were also significantly more active with CHO. This is the first demonstration that oral carbohydrate signalling can increase activation within the primary sensorimotor cortex during physical activity and enhance activation of neural networks involved in sensory perception.
authors.affiliation: Exercise Neurometabolism Laboratory, Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Turner
authors.affiliation: Movement Neuroscience Laboratory, Centre for Brain Research, The University of Auckland, New Zealand.
authors.forename: Winston D
authors.initials: WD
authors.lastname: Byblow
authors.affiliation: Department of Medicine, Centre for Brain Research, The University of Auckland, New Zealand.
authors.forename: Cathy M
authors.initials: CM
authors.lastname: Stinear
authors.affiliation: Exercise Neurometabolism Laboratory, Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: n.gant@auckland.ac.nz.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Gant
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity; D009055:Mouth / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology; D012677:Sensation; D013649:Taste; D055697:Taste Perception; D014796:Visual Perception; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates
keywords: Carbohydrate; Magnetic resonance imaging; Physical activity; Sensorimotor integration; Taste receptors