Effect of vertical linear acceleration on H-reflex in decerebrate cat. II. Sinusoidal stimuli.

1981 ◽  
Vol 45 (4) ◽  
pp. 656-666 ◽  
Author(s):  
D G Watt
Keyword(s):  
Linear Acceleration ◽  
H Reflex ◽  
Decerebrate Cat ◽  
Vertical Linear Acceleration

Maturation of otolith-related brainstem neurons in the detection of vertical linear acceleration in rats

2006 ◽  
Vol 23 (9) ◽  
pp. 2431-2446 ◽  
Author(s):  
Suk-King Lai ◽  
Chun-Hong Lai ◽  
Ken K. L. Yung ◽  
Daisy K. Y. Shum ◽  
Ying-Shing Chan
Keyword(s):  
Linear Acceleration ◽  
Vertical Linear Acceleration

Postlesional Vestibular Reorganization Improves the Gain But Impairs the Spatial Tuning of the Maculo-Ocular Reflex in Frogs

2003 ◽  
Vol 90 (6) ◽  
pp. 3736-3749 ◽  
Author(s):  
Martin Rohregger ◽  
Norbert Dieringer
Keyword(s):  
Linear Acceleration ◽  
Abducens Nerve ◽  
Nerve Fibers ◽  
Afferent Nerve ◽  
Nerve Lesion ◽  
Synaptic Reorganization ◽  
Response Component ◽  
Spatial Tuning ◽  
Vertical Linear Acceleration

The ramus anterior (RA) of N.VIII was sectioned unilaterally. Two months later we analyzed in vivo responses of the ipsi- and of the contralesional abducens nerve during horizontal and vertical linear acceleration in darkness. The contralesional abducens nerve had become responsive again to linear acceleration either because of a synaptic reorganization in the vestibular nuclei on the operated side and/or because of a reinnervation of the utricular macula by regenerating afferent nerve fibers. Significant differences in the onset latencies and in the acceleration sensitivities allowed a separation of RA frogs in a group without and in a group with functional utricular reinnervation. Most important, the vector orientation for maximal abducens nerve responses was clearly altered: postlesional synaptic reorganization resulted in the emergence of abducens nerve responses to vertical linear acceleration, a response component that was barely detectable in RA frogs with utricular reinnervation and that was absent in controls. The ipsilesional abducens nerve, however, exhibited unaltered responses in either group of RA frogs. The altered spatial tuning properties of contralesional abducens nerve responses are a direct consequence of the postlesional expansion of signals from intact afferent nerve and excitatory commissural fibers onto disfacilitated 2nd-order vestibular neurons on the operated side. These results corroborate the notion that postlesional vestibular reorganization activates a basic neural reaction pattern with more beneficial results at the cellular than at the network level. However, given that the underlying mechanism is activityrelated, rehabilitative training after vestibular nerve lesion can be expected to shape the ongoing reorganization.

Spatial organization of linear vestibuloocular reflexes of the rat: responses during horizontal and vertical linear acceleration

1991 ◽  
Vol 66 (6) ◽  
pp. 1805-1818 ◽  
Author(s):  
B. J. Hess ◽  
N. Dieringer
Keyword(s):  
Eye Movements ◽  
Spatial Organization ◽  
Head Tilt ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Viewing Distance ◽  
Phase Lag ◽  
Linear Motion ◽  
Common Reference ◽  
Vertical Linear Acceleration

1. The spatial properties of linear vestibuloocular reflexes (LVOR) were studied in pigmented rats in response to sinusoidal linear acceleration on a sled. The orientation of the animal on the sled was altered in 15 degrees steps over the range of 360 degrees. Horizontal, vertical, and torsional components of eye movements were recorded with the magnetic field search coil technique in complete darkness. Conjugacy of the two eyes was studied in the horizontal movement plane. 2. Acceleration along the optic axis of one eye (approximately 50 degrees lateral) induced maximal vertical responses in the ipsilateral eye and, at the same time, maximal torsional responses in the contralateral eye. These vertical and torsional responses of the LVOR coincide with those obtained when the respective coplanar vertical semicircular canals are stimulated. Such a congruence suggests a common reference frame for LVOR and angular vestibuloocular reflexes (AVOR), with the result that direct combination of signals indicating apparent and real head tilt is facilitated. 3. Transformations of vertical and torsional responses into head coordinates (pitch and roll) show that these movements are compensatory in direction for any combination of apparent head tilt in pitch and roll planes. 4. Gain (rotation of the eye/apparent rotation of the gravity direction) was approximately 0.3 at 0.1 Hz and decreased to approximately 0.1 at 1.0 Hz. Vertical responses tended to have a larger gain than torsional responses. Phase lag relative to peak acceleration increased from about -9 degrees to about -47 degrees over the same frequency range. 5. Vertical linear acceleration evoked only vertical eye movements at a frequency of 1.0 Hz. 6. Horizontal responses of both eyes were symmetric or asymmetric in amplitude and in-phase (conjugate) or out-of-phase (disconjugate) with respect to each other, depending on the direction of linear acceleration. Translation in the transverse direction evoked conjugate compensatory horizontal responses. Forward-backward translation evoked movements of both eyes that were symmetric in amplitude, but 180 degrees out-of-phase. Translation along diagonal axes evoked almost no horizontal responses in the eye facing in the direction of linear motion but maximal horizontal responses in the eye facing away from the direction of linear motion. These disconjugate movements resulted in a modulation of the vergence angle of the eyes. 7. Disconjugate horizontal responses in darkness are best explained by the assumption that part of the visual consequences of a translational head displacement (i.e., change of viewing distance in light) is taken into account centrally.(ABSTRACT TRUNCATED AT 400 WORDS)

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