title: Functional and anatomical basis for brain plasticity in facial palsy rehabilitation using the masseteric nerve.
abstract: Several techniques have been described for smile restoration after facial nerve paralysis. When a nerve other than the contralateral facial nerve is used to restore the smile, some controversy appears because of the nonphysiological mechanism of smile recovering. Different authors have reported natural results with the masseter nerve. The physiological pathways which determine whether this is achieved continue to remain unclear. Using functional magnetic resonance imaging, brain activation pattern measuring blood-oxygen-level-dependent (BOLD) signal during smiling and jaw clenching was recorded in a group of 24 healthy subjects (11 females). Effective connectivity of premotor regions was also compared in both tasks. The brain activation pattern was similar for smile and jaw-clenching tasks. Smile activations showed topographic overlap though more extended for smile than clenching. Gender comparisons during facial movements, according to kinematics and BOLD signal, did not reveal significant differences. Effective connectivity results of psychophysiological interaction (PPI) from the same seeds located in bilateral facial premotor regions showed significant task and gender differences (p < 0.001). The hypothesis of brain plasticity between the facial nerve and masseter nerve areas is supported by the broad cortical overlap in the representation of facial and masseter muscles.
authors.affiliation: Plastic and Reconstructive Surgery Department, Clinica Universidad de Navarra, University of Navarra, 31008 Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Buendia
authors.affiliation: Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28031, Madrid, Spain.
authors.forename: Francis R
authors.initials: FR
authors.lastname: Loayza
authors.affiliation: Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28031, Madrid, Spain.
authors.forename: Elkin O
authors.initials: EO
authors.lastname: Luis
authors.affiliation: Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28031, Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Celorrio
authors.affiliation: Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28031, Madrid, Spain. Electronic address: mapastor@unav.es.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Pastor
authors.affiliation: Plastic and Reconstructive Surgery Department, Clinica Universidad de Navarra, University of Navarra, 31008 Pamplona, Spain. Electronic address: bhontanill@unav.es.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Hontanilla
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D004558:Electric Stimulation; D005149:Facial Expression; D005154:Facial Nerve / Q000033:anatomy & histology*; D005158:Facial Paralysis / Q000175:diagnosis / Q000534:rehabilitation / Q000601:surgery*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007568:Jaw / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008406:Masseter Muscle / Q000294:innervation*; D008875:Middle Aged; D016067:Nerve Transfer / Q000379:methods*; D009473:Neuronal Plasticity / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D012016:Reference Values; D012904:Smiling / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: BOLD; Cortical representation; Facial; Facial palsy; Functional magnetic resonance imaging; Masseter