Functional assessments of the rodent facial nerve: A synkinesis model

Tessa Hadlock, Jeffrey Kowaleski, David Lo, Roberto Bermejo, H. Philip Zeigler, Susan Mackinnon, James T. Heaton

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Objectives/Hypothesis: Rodent whisker movement has been used as a tool, after facial nerve manipulation, to quantify functional recovery. We have recently established a method to study functional correlates of aberrant regeneration of the facial nerve. Our objective was to establish normative parameters for both spontaneous and induced whisking and blinking behavior in a large group of normal rats. Study Design: Prospective animal study. Methods: Eighty animals underwent quantitative facial movement testing to measure simultaneous vibrissal movement and ocular closure for each side independently. Right and left C-l whisker positions were continuously recorded for 5-minute sessions, and changes in infrared detection corresponding to eye closure were continuously recorded. Whisking and blinking were elicited by delivery of olfactory stimuli (10 s scented airflows) and corneal air puffs. Whisks were counted and analyzed, and eye closures were counted. Results: Whisking amplitude, velocity, and acceleration were consistent with literature values. Air puff delivery elicited an ipsilateral blink 99% of the time, a contralateral blink 18% of the time, and changes in or initiation of bilateral whisking 70% of the time. Olfactory stimulus delivery prompted a change in whisking behavior 83% of the time, and eye closure 20% of the time. Conclusions: This study establishes normative data for assessing cranial nerve VII-controlled facial movement in four separate facial regions. We demonstrate the capability and tendency of animals to move their orbicularis oculi muscles independently of and simulta-neously with their midfacial muscles. This model pro-v des an excellent tool for the study of aberrant regen-eration after facial nerve injury in the rodent.

Original languageEnglish
Pages (from-to)1744-1749
Number of pages6
JournalLaryngoscope
Volume118
Issue number10
DOIs
StatePublished - Oct 1 2008

Keywords

  • Kinematics
  • Rodent facial nerve
  • Synkinesis
  • Whisking

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    Hadlock, T., Kowaleski, J., Lo, D., Bermejo, R., Zeigler, H. P., Mackinnon, S., & Heaton, J. T. (2008). Functional assessments of the rodent facial nerve: A synkinesis model. Laryngoscope, 118(10), 1744-1749. https://doi.org/10.1097/MLG.0b013e31817f5255