The interstitial nucleus of the superior fasciculus, posterior bundle (INSFp) in the guinea pig: Another nucleus of the accessory optic system processing the vertical retinal slip signal

1989 ◽  
Vol 2 (4) ◽  
pp. 377-382 ◽  
Author(s):  
C. Benassi ◽  
G. P. Biral ◽  
F. Lui ◽  
C. A. Porro ◽  
R. Corazza
Keyword(s):  
Guinea Pig ◽  
Optokinetic Nystagmus ◽  
Vertical Direction ◽  
Luminous Flux ◽  
Visual Signals ◽  
Optic System ◽  
Accessory Optic System ◽  
Retinal Slip ◽  
Visual Patterns ◽  
Medial Terminal Nucleus

AbstractAs in rabbit, gerbil, and rat, the guinea pig interstitial nucleus of the superior fasciculus, posterior bundle (INSFp) is a sparse assemblage of neurons scattered among the fibers forming the fasciculus bearing this name. Most of the INSFp neurons are small and are ovoid in shape. Interspersed among these, are a few larger, elongated neurons whose density becomes greater and whose shape becomes fusiform in correspondence to the zone of transition from the superior fasciculus to the ventral part of the medial terminal nucleus (MTN). Like the MTN, the INSFp is activated by retinal-slip signals evoked by whole-field visual patterns moving in the vertical direction, as shown by the increase of 14C-2-deoxyglucose (2DG) uptake into this nucleus. At the same level of luminous flux, neither pattern moving in the horizontal direction nor the same pattern held stationary can elicit increases in the INSFp 2DG assumption. The specificity of the observed increases in metabolic rates in INSFp following vertical whole-field motion suggests that this assemblage of neurons relays visual signals used in the control of vertical optokinetic nystagmus.

A model for optokinetic eye movements in turtles that incorporates properties of retinal-slip neurons

1996 ◽  
Vol 13 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Alexander F. Rosenberg ◽  
Michael Ariel
Keyword(s):  
Eye Movements ◽  
Simulation Software ◽  
Visual Signals ◽  
Velocity Storage ◽  
Visual Response ◽  
Optic System ◽  
Accessory Optic System ◽  
Optokinetic Response ◽  
Retinal Slip ◽  
Optokinetic Reflex

AbstractThe turtle's optokinetic response is described by a simple model that incorporates visual-response properties of neurons in the pretectum and accessory optic system. Using data from neuronal and eye-movement recordings that have been previously published, the model was realized using algebraic-block simulation software. It was found that the optokinetic response, modelled as a simple negative feedback system, was similar to that measured from a behaving animal. Because the responses of retinal-slip detecting neurons corresponded to the nonlinear, closed-loop optokinetic response, it was concluded that the visual signals encoded in these neurons could provide sufficient sensory information to drive the optokinetic reflex. Furthermore, it appears that the low gain of optokinetic eye movements in turtles, which have a negligible velocity storage time constant, may allow stable oculomotor output in spite of neuronal delays in the reflex pathway. This model illustrates how visual neurons in the pretectum and accessory optic system can contribute to visually guided eye movements.

Macaque accessory optic system: I. Definition of the medial terminal nucleus

1990 ◽  
Vol 302 (2) ◽  
pp. 394-404 ◽  
Author(s):  
Howard M. Cooper ◽  
Christine Baleydier ◽  
Michel Magnin
Keyword(s):  
Optic System ◽  
Accessory Optic System ◽  
Definition Of ◽  
Medial Terminal Nucleus

Optokinetic Nystagmus and the Accessory Optic System of Pigeon and Turtle

1979 ◽  
Vol 16 (3) ◽  
pp. 192-202 ◽  
Author(s):  
Katherine V. Fite ◽  
Anton Reiner ◽  
Stephen P. Hunt
Keyword(s):  
Optokinetic Nystagmus ◽  
Optic System ◽  
Accessory Optic System

Independent eye movements in the turtle

1990 ◽  
Vol 5 (1) ◽  
pp. 29-41 ◽  
Author(s):  
M. Ariel
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Contact Lenses ◽  
The Other ◽  
Slow Phase ◽  
Accessory Optic System ◽  
Retinal Slip ◽  
The Mean ◽  
The Difference ◽  
Eye Velocity

AbstractIn order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).

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