Whisking in Air: Encoding of Kinematics by Trigeminal Ganglion Neurons in Awake Rats

• Published in: Journal of neurophysiology Vol. 101; no. 4; pp. 1836 - 1846
• Main Authors: Khatri, V, Bermejo, R, Brumberg, J. C, Keller, A, Zeigler, H. P
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.04.2009; American Physiological Society
• Subjects: Action Potentials - physiology; Air; Animals; Biomechanical Phenomena - physiology; Conditioning, Operant - physiology; Female; Movement - physiology; Neurons - physiology; Rats; Rats, Long-Evans; Reinforcement Schedule; ROC Curve; Statistics as Topic; Trigeminal Ganglion - cytology; Vibrissae - innervation; Wakefulness
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.90655.2008

1 Department of Hearing and Speech Sciences, Vanderbilt University Nashville, Tennessee; 2 Department of Psychology, Hunter College New York; 3 Department of Psychology, Queens College, Queens, New York; and 4 Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland Submitted 10 June 2008; accepted in final form 17 December 2008 Active sensing requires the brain to distinguish signals produced by external inputs from those generated by the animal's own movements. Because the rodent whisker musculature lacks proprioceptors, we asked whether trigeminal ganglion neurons encode the kinematics of the rat's own whisker movements in air. By examining the role of kinematics, we have extended previous findings showing that many neurons that respond during such movements do not do so consistently. Nevertheless, the majority ( 70%) of trigeminal ganglion neurons display significant correlations between firing rate and a kinematic parameter, and a subset, 30%, represent kinematics with high reliability. Preferential firing to movement direction was observed but was strongly modulated by movement amplitude and speed. However, in contrast to the precise time-locking that occurs in response to active whisker contacts, whisker movements in air generate temporally dispersed responses that are not time-locked to the onset of either protractions or retractions. Address for reprint requests and other correspondence: V. Khatri, Dept. of Hearing and Speech Sciences, 465 21st Ave. South, 7114 MRB III, Vanderbilt University Nashville, TN (E-mail: khatri1976{at}gmail.com )