Gravity is an important context for adapting the angular vestibulo-ocular reflex (aVOR) by visual-vestibular mismatch. Maximal gain changes occur in the position of adaptation and decrease, as the head is oriented away from this position. The spectral components of the gravity-dependent adaptation are also tuned to the frequency of adaptation. A study is proposed to determine the cellular basis for the gravity and frequency dependent aspects of this adaptation in the vestibular nuclei of the alert monkey. The frequency characteristics of gravity dependent adaptation will first be studied to determine how adaptation at one frequency affects adaptation over a wide range of frequencies and head orientations. This will lay the groundwork for studying adaptive changes in canal-ocular transduction and reorientation of otolith polarization vectors in central vestibular neurons. Such studies will include: 1) Characterizing the cellular changes associated with gravity-dependent adaptation in the otolith polarization vectors of otolith-canal convergent neurons in the vestibular nuclei. 2) Investigating how adaptive changes in the otolith reorientation and canal-ocular transduction of canal-otolith convergent neurons at a particular frequency are related to the spatio-temporal convergence (STC) characteristics of the unit. Preliminary investigations show that when gravity-dependent adaptation is induced at a specific frequency, the canal-otolith convergent neurons developed STC characteristics that also tuned to the frequency of adaptation. 3) Determine how FTN and PVP neurons code the gravity-dependent adaptation. 4) Tie these findings to a neuronal net model, which will form the underlying basis for the study. It is postulated that gravity- dependent adaptation is a spatio-temporal process, which is encoded in the STC characteristics of canal- otolith convergent units. It is further proposed that vestibular-only (VO) neurons in the vestibular nuclei transmit this information through the flocculus to floccular target neurons (FTN) and directly to position- vestibular-pause (PVP) cells that code gravity dependent adaptation.The proposed research will determine the neural mechanism for the dependence of adaptation of the vestibulo-ocular reflex on gravity. This could provide a new approach to explaining difficulties in balance and spatial orientation commonly encountered after lesions of the vestibular system.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
3R01DC004996-07S1
Application #
7853730
Study Section
Sensorimotor Integration Study Section (SMI)
Program Officer
Platt, Christopher
Project Start
2009-07-01
Project End
2010-06-30
Budget Start
2009-07-01
Budget End
2010-06-30
Support Year
7
Fiscal Year
2009
Total Cost
$92,745
Indirect Cost
Name
Icahn School of Medicine at Mount Sinai
Department
Neurology
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Yakushin, Sergei B; Martinelli, Giorgio P; Raphan, Theodore et al. (2014) Vasovagal oscillations and vasovagal responses produced by the vestibulo-sympathetic reflex in the rat. Front Neurol 5:37
Cohen, Bernard; Martinelli, Giorgio P; Raphan, Theodore et al. (2013) The vasovagal response of the rat: its relation to the vestibulosympathetic reflex and to Mayer waves. FASEB J 27:2564-72
Yakushin, Sergei B (2012) Tuning of gravity-dependent and gravity-independent vertical angular VOR gain changes by frequency of adaptation. J Neurophysiol 107:3349-56
Holstein, Gay R; Friedrich Jr, Victor L; Martinelli, Giorgio P et al. (2012) Fos expression in neurons of the rat vestibulo-autonomic pathway activated by sinusoidal galvanic vestibular stimulation. Front Neurol 3:4
Xiang, Yongqing; Yakushin, Sergei B; Raphan, Theodore (2012) Modeling spatial tuning of adaptation of the angular vestibulo-ocular reflex. Exp Brain Res 220:165-78
Yakushin, Sergei B; Dai, Mingjia; Raphan, Theodore et al. (2011) Spatial orientation of the angular vestibulo-ocular reflex (aVOR) after semicircular canal plugging and canal nerve section. Exp Brain Res 210:583-94
Cohen, Bernard; Yakushin, Sergei B; Holstein, Gay R (2011) What does galvanic vestibular stimulation actually activate? Front Neurol 2:90
Kolesnikova, Olga V; Raphan, Theodore; Cohen, Bernard et al. (2011) Orientation adaptation of eye movement-related vestibular neurons due to prolonged head tilt. Ann N Y Acad Sci 1233:214-8
Cohen, Bernard; Martinelli, Giorgio P; Ogorodnikov, Dmitri et al. (2011) Sinusoidal galvanic vestibular stimulation (sGVS) induces a vasovagal response in the rat. Exp Brain Res 210:45-55
Yakushin, Sergei B; Kolesnikova, Olga V; Cohen, Bernard et al. (2011) Complementary gain modifications of the cervico-ocular (COR) and angular vestibulo-ocular (aVOR) reflexes after canal plugging. Exp Brain Res 210:549-60

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