No abstract available.
Vestibular Nuclei*

No abstract available.
Chinchilla* ; Vestibular Nerve* ; Vestibular Nuclei*

No abstract available.
Infarction ; Neurons ; Vestibular Nuclei

No abstract available.
Gerbillinae* ; Vestibular Nuclei*

BACKGROUND AND OBJECTIVES: The present study investigated the role of the peripheral vestibular end organ in vestibular symptoms and temporal changes in expression of c-Fos protein in the vestibular nuclei following anterior inferior cerebellar artery (AICA) occlusion using rats with unilateral or bilateral labyrinthectomy. MATERIALS AND METHODS: Expression of c-Fos protein in the vestibular nuclei was measured 2, 12, 24, and 48 hours after AICA occlusion. RESULTS: Unilateral AICA occlusion significantly induced expression of c-Fos protein bilaterally in the medial, inferior, superior, and lateral vestibular nuclei. Following AICA occlusion, the medial vestibular nucleus (MVN) showed the highest expression of c-Fos protein among the 4 vestibular nuclei. The expression of c-Fos protein was asymmetric between the bilateral MVN, showing higher expression in the MVN contralateral to the side of AICA occlusion compared to the ipsilateral MVN. The degree of asymmetry in c-Fos protein expression between the bilateral MVN peaked 12 hours after AICA occlusion. The expression of c-Fos protein gradually decreased 24 hours after AICA occlusion and returned to control levels 48 hours after AICA occlusion. Unilateral labyrinthectomy significantly decreased expression of c-Fos protein in the MVN ipsilateral to the side of labyrinthectomy following AICA occlusion. Moreover, bilateral labyrinthectomy significantly decreased expression of c-Fos protein in the bilateral MVN flowing AICA occlusion. CONCLUSION: These results suggest that afferent signals from the peripheral vestibular end organ are crucial to the expression of c-Fos protein in the MVN following AICA occlusion and that expression of c-Fos protein is sustained for 24 hours after AICA occlusion.
Animals ; Arteries ; Rats ; Vertebrobasilar Insufficiency ; Vestibular Nuclei

Some individuals may demonstrate a secondary phase nystagmus (SPN) following the caloric irrigation. It has been stated that if a SPN begins prior to 140 seconds after the onset of caloric stimulation and if the magnitude of the slow phase velocity is greater than 6 degrees/sec, then a premature reversal caloric nystagmus (PRCN) is said to exit. Thus far, there have been no reports describing PRCN in Korea. We described a typical PRCN in a patient with medulloblastoma within the 4th ventricle. The patient had a gaze-evoked horizontal and upbeating nystagmus. However, there was no indication of spontaneous nystagmus. A monothermal caloric test was administered. The initial left beating primary phase nystagmus was subsided at 60 seconds after right cold water stimulation and at 110 seconds, a right beating SPN with 14 degrees/sec of slow phase velocity was appeared and was continuous for 240 seconds. Although the precise mechanism of PRCN is unknown, vestibular nuclei damage may be related.
Caloric Tests ; Humans ; Korea ; Medulloblastoma ; Nystagmus, Physiologic* ; Vestibular Nuclei ; Water

To search the correlations between electrical activity and c-Fos expression in the process of vestibular compensation, we examined the changes of those two parameters in the medial vestibular nuclei (MVN) of unilaterally labyrinthectomized (ULX) rats. Spontaneous nystagmus with fast component toward the intact side disappeared gradually within 48 hours. Fourty eight hours after ULX, directional preponderance of the eye movement induced by sinusoidal rotation of the whole body which represents the symmetry of bilateral vestibular functions showed less than 20% by rotation of 0.1, 0.2, and 0.5 Hz, indicating the recovery of symmetry in bilateral vestibular functions. Six hours after ULX, spontaneous electrical activity of type I neurons resulted in asymmetry between bilateral MVN, however, the asymmetry of the electrical activity was decreased 48 hours after ULX. Immunocytochemical staining revealed that ULX produced dramatic induction of c-Fos positive cells in the MVN bilaterally. The number of c-Fos immunoreactive cells in the contralateral MVN was significantly higher than those in the ipsilateral MVN (p<0.0001) 2 hours after ULX. Thereafter, the number of c-Fos positive cells decreased bilaterally and was slightly, but not significantly higher in the ipsilateral MVN at 48 hours after ULX. The present results suggest that both electrical activity of type I neurons and c-Fos expression in MVN following ULX will reflect underlying mechanisms of recovery process of vestibular compensation.
Animals ; Compensation and Redress ; Eye Movements ; Neurons* ; Rats* ; Vestibular Nuclei*

The purpose of this study was to evaluate the effects of electrical stimulation on vestibular compensation following ULX in rats. Electrical stimulation (ES) with square pulse (100 ~ 300 uA, 1.0 ms, 100 Hz) was applied to ampullary portion bilaterally for 6 and 24 hours in rats receiving ULX. After ES, animals that showed the recovery of vestibular symptoms by counting and comparing the number of spontaneous nystagmus were selected for recording resting activity of type I, II neurons in the medial vestibular nuclei (MVN) of the lesioned side. And then the dynamic neuronal activities were recorded during sinusoidal rotation at a frequency of 0.1 Hz and 0.2 Hz. The number of spontaneous nystagmus was significantly different 24 hours (p< 0.01, n = 10), but not 6 hours after ULX+ES. As reported by others, the great reduction of resting activity only in the type I neurons ipsilateral to lesioned side was observed 6, 24 hours after ULX compared to that of intact labyrinthine animal. However, the significant elevation (p < 0.01) of type I and reduction (p < 0.01) of type II neuronal activity were seen 24 hours after ULX+ES. Interestingly, gain, expressed as maximum neuronal activity(spikes/sec)/maximum rotational velocity (deg/sec), was increased in type I cells and decreased in type II cells 24 hours after ULX+ES in response to sinusoidal rotation at frequencies of both 0.1 Hz and 0.2 Hz. This result suggests that accompanying the behavioral recovery, the electrical stimulation after ULX has beneficial effects on vestibular compensation, especially static symptoms (spontaneous nystagmus), by enhancing resting activity of type I neurons and reducing that of type II neurons.
Animals ; Compensation and Redress ; Electric Stimulation* ; Neurons* ; Rats* ; Vestibular Nuclei*

Periodic alternating nystagmus (PAN) is characterized by a periodical reversal in the direction of the nystagmus. Acquired PAN is caused by lesions of the inferior cerebellar vermis, causing disinhibition of the velocity storage mechanism, which is mediated by the vestibular nuclei. An eighty-year-old woman with abscess in midline cerebellum experienced dizziness and imbalance. We observed short period PAN with 7-8 seconds.
Abscess ; Cerebellum ; Dizziness ; Female ; Humans ; Nystagmus, Pathologic ; Vestibular Nuclei

BACKGROUND: There is a little information about the effect of selective vestibular stimulation on the expression of activity-dependent metabolic markers in the vestibular nuclei. The purpose of this study was to evaluate effect of afferent excitation of the horizontal semicircular canal on expression of phosphorylated ERK1/2 (pERK1/2) and cFos proteins in the vestibular nuclei. METHODS: The horizontal semicircular canal of Sprague-Dawley rats was selectively stimulated by using the sinusoidal horizontal stimulator with 10-minute duration of stimulation. Conventional immunohistochemical method was used to visualize pERK1/2 or cFos immunoreactive neurons in the vestibular nuclei following rotation. RESULTS: Five minutes after stimulation of the horizontal semicircular canal there was a high expression of pERK1/2 protein in the medial vestibular nucleus among 4 major subnuclei of the central vestibular nuclear complex. On the contrary, immunoreactivity of cFos protein was observed in the medial and inferior vestibular nucleus 2 hours after horizontal sinusoidal rotation. The lateral vestibular nucleus was free from the expression of pERK1/2 and cFos proteins in response to excitation of the horizontal semicircular canal. However, in the vestibular nuclei of unilaterally labyrinthectomized rats expression of pERK and cFos proteins was markedly suppressed in ipsi-lesional side as well as contra-lesional side following stimulation of the horizontal semicircular canal. Furthermore no expression of pERK1/2 and cFos protein in the bilateral vestibular nuclei of bilaterally labyrinthectomized rats was noted after stimulation of the horizontal semicircular canal. CONCLUSIONS: Therefore these results of present study suggest that excitatory afferent signals from the peripheral vestibular receptors are essential for protein translation for pERK1/2 and cFos in response to stimulation of the semicircular canal.
Animals ; Neurons ; Protein Biosynthesis ; Rats ; Rats, Sprague-Dawley ; Semicircular Canals* ; Vestibular Nuclei* ; Vestibular Nucleus, Lateral