Vestibular nuclei activity and eye movements in the alert monkey during sinusoidal optokinetic stimulation

1985 ◽  
Vol 57 (2) ◽  
Author(s):  
R. Boyle ◽  
U. B�ttner ◽  
G. Markert
Keyword(s):  
Eye Movements ◽  
Vestibular Nuclei ◽  
Optokinetic Stimulation ◽  
Alert Monkey ◽  
Vestibular Nuclei Activity ◽  
Sinusoidal Optokinetic Stimulation

Unit activity in vestibular nucleus of the alert monkey during horizontal angular acceleration and eye movement

1975 ◽  
Vol 38 (5) ◽  
pp. 1140-1161 ◽  
Author(s):  
A. F. Fuchs ◽  
J. Kimm
Keyword(s):  
Eye Movements ◽  
Vestibular Nucleus ◽  
Angular Acceleration ◽  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Button Press ◽  
Alert Monkey ◽  
Unit Discharge ◽  
Relationship Of ◽  
The Relationship

Single units were recorded from the vestibular nuclei of unanesthetized monkeys that were rotated in the horizontal plane while simultaneously pressing individual buttons in a controlled array which turned with hem. Using this behavioral paradigm, it was possible to 1) determine the relationship of unit discharge to eye movements measured by the DC-coupled electrooculogram and calibrated by the button-press task, and 2) determine the relationship of unit discharge to horizontal acceleration, either with or without the compensatory eye movements evoked by vestibular stimulation. Based on their responses during vestibular stimulation and/or eye movements, neurons in the vestibular nuclei (77% of our sample was in the medial nucleus) could be divided into four groups...

Abducens internuclear neurons carry an inappropriate signal for ocular convergence

1989 ◽  
Vol 62 (1) ◽  
pp. 70-81 ◽  
Author(s):  
P. D. Gamlin ◽  
J. W. Gnadt ◽  
L. E. Mays
Keyword(s):  
Eye Movements ◽  
Action Potentials ◽  
Vestibular Nuclei ◽  
Lateral Rectus ◽  
Medial Rectus ◽  
Medial Longitudinal Fasciculus ◽  
Unit Recording ◽  
Antidromic Activation ◽  
Prepositus Hypoglossi ◽  
Ocular Convergence

1. Single-unit recording studies in alert Rhesus monkeys characterized the vergence signal carried by abducens internuclear neurons. These cells were identified by antidromic activation and the collision of spontaneous with antidromic action potentials. The behavior of abducens internuclear neurons during vergence was compared with that of horizontal burst-tonic fibers in the medial longitudinal fasciculus (MLF) and to that of a large sample of unidentified abducens cells (presumably both motoneurons and internuclear neurons). 2. The results indicate that abducens internuclear neurons and lateral rectus motoneurons behave similarly during vergence eye movements: the majority of both groups of cells decrease their firing rate for convergence eye movements: a minority show no change for vergence. This finding is strongly supported by recordings of horizontal burst-tonic fibers in the MLF, the majority of which decrease their activity significantly for convergence eye movements. 3. These findings indicate that a net inappropriate vergence signal is sent to medial rectus motoneurons via the abducens internuclear pathway. Because medial rectus motoneurons increase their activity appropriately during symmetrical convergence, this inappropriate MLF signal must be overcome by a more potent direct vergence input. 4. Overall, both abducens internuclear neurons and lateral rectus motoneurons decrease their activity for convergence less than would be expected based on their conjugate gain. This implies that some degree of co-contraction of the lateral and medial rectus muscles occurs during convergence eye movements. 5. Some horizontal burst-tonic MLF fibers decrease their activity more for convergence than any recorded abducens neuron. These fibers may arise from cells in the nucleus prepositus hypoglossi or vestibular nuclei.

Eye-Head Coordination during Optokinetic Stimulation in Squirrel Monkeys

1981 ◽  
Vol 90 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Takeshi Kubo ◽  
David W. Jensen ◽  
Makoto Igarashi ◽  
Jerry L. Homick
Keyword(s):  
Statistical Analysis ◽  
Eye Movements ◽  
Negative Correlation ◽  
Guinea Pigs ◽  
Significant Negative Correlation ◽  
Squirrel Monkeys ◽  
Slow Phase ◽  
Optokinetic Stimulation ◽  
The Gaze ◽  
Significant Difference

Head and eye movements in the yaw plane were recorded during and after optokinetic stimulation in squirrel monkeys. 1) Phasic or tonic head deviations to the side of the ocular quick phase occurred in 94% of total recordings (n = 50) during the perstimulus period, and in 75% of recordings (n = 49) during the poststimulus period. Magnitude of mean head deviation was significantly different between perstimulus and poststimulus periods. 2) Head nystagmus associated with eye nystagmus was consistently observed in seven of nine squirrel monkeys during optokinetic stimulation. Squirrel monkeys are thereby less prone to display head nystagmus than either guinea pigs, pigeons or chickens. 3) Slow phase speeds of coupled head and eye nystagmus were subjected to statistical analysis. A highly significant negative correlation was found between slow phase head and eye speeds. The correlation coefficient was −0.81 at 60°/sec stimulus (n = 119) and −0.72 at 100°/sec stimulus (n = 131). The gaze speed, calculated by summing the head and eye speeds, was 59.1 ± 6.8/sec at 60°/sec and 92.2 ± 11.4 at 100°/sec stimulus. There was no significant difference between the gaze speed in a free head condition and the eye speed when the head was fixed.

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