Monocular contour perception under the influence of prior stimulation of the contralateral eye

1960 ◽  
Vol 10 (2) ◽  
pp. 123-130
Author(s):  
W. L. Gulick
Keyword(s):  
Contour Perception ◽  
Contralateral Eye ◽  
Stimulation Of

Connexions Between a Movement-Detecting Visual Interneurone and Flight Motoneurones of a Locust

1980 ◽  
Vol 86 (1) ◽  
pp. 87-97
Author(s):  
PETER SIMMONS
Keyword(s):  
Movement Detector ◽  
Excitatory Postsynaptic Potentials ◽  
Schistocerca Americana ◽  
Postsynaptic Potentials ◽  
Contralateral Movement ◽  
Contralateral Eye ◽  
Stimulation Of

Both of the descending contralateral movement detector (DCMD) neurones of Schistocerca americana gregaria, which respond to stimulation of the contralateral eye or to loud noises, mediate excitatory postsynaptic potentials in most ipsilateral flight motoneurones.

Contralateral conjugate eye deviation during deep brain stimulation of the subthalamic nucleus

2007 ◽  
Vol 107 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Donald C. Shields ◽  
Alessandra Gorgulho ◽  
Eric Behnke ◽  
Dennis Malkasian ◽  
Antonio A. F. Desalles
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Internal Capsule ◽  
High Frequency Stimulation ◽  
Frontal Eye Field ◽  
Current Spread ◽  
Frequency Stimulation ◽  
Contralateral Eye ◽  
Deep Brain ◽  
Stimulation Of

Object Deep brain stimulation of the subthalamic nucleus (STN) in patients with Parkinson disease is often very effective for treatment of debilitating motor symptoms. Nevertheless, the small size of the STN and its proximity to axonal projections results in multiple side effects during high-frequency stimulation. Contralateral eye deviation is produced in a small percentage of patients, but the precise mechanism of this side effect is at present poorly understood. Methods Contralateral eye deviation was produced by high-frequency stimulation of 22 contact sites in nine patients undergoing deep brain stimulation of the STN. The precise locations of these contacts were calculated and compiled in order to locate the stimulated structure responsible for eye deviation. Results The mean x, y, and z coordinates associated with contralateral eye deviation were found to be 11.57, 2.03, and 3.83 mm lateral, posterior, and inferior to the anterior commissure–posterior commissure midpoint, respectively. The point described by these coordinates is located within the lateral anterosuperior border of the STN. Conclusions Given that stimulation of frontal eye field cortical regions produces similar contralateral conjugate eye deviation, these results are best explained by electrical current spread to nearby frontal eye field axons coursing lateral to the STN within the internal capsule. Thus, placement of the implanted electrode in a more medial, posterior, and inferior position may bring resolution of these symptoms by reducing the amount of current spread to internal capsule axons.

Responses of pigeon vestibulocerebellar neurons to optokinetic stimulation. II. The 3-dimensional reference frame of rotation neurons in the flocculus

1993 ◽  
Vol 70 (6) ◽  
pp. 2647-2659 ◽  
Author(s):  
D. R. Wylie ◽  
B. J. Frost
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Receptive Fields ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Monocular Stimulation ◽  
Contralateral Eye ◽  
Ipsilateral Stimulation ◽  
Stimulation Of

1. The complex spike activity of Purkinje cells in the flocculus in response to rotational flowfields was recorded extracellularly in anesthetized pigeons. 2. The optokinetic stimulus was produced by a rotating “planetarium projector.” A light source was placed in the center of a tin cylinder, which was pierced with numerous small holes. A pen motor oscillated the cylinder about its long axis. This apparatus was placed above the bird's head and the resultant rotational flow-field was projected onto screens that surrounded the bird on all four sides. The axis of rotation of the planetarium could be oriented to any position in three-dimensional space. 3. Two types of responses were found: vertical axis (VA; n = 43) neurons responded best to visual rotation about the vertical axis, and H-135i neurons (n = 34) responded best to rotation about a horizontal axis. The preferred orientation of the horizontal axis was at approximately 135 degrees ipsilateral azimuth. VA neurons were excited by rotation about the vertical axis producing forward (temporal to nasal) and backward motion in the ipsilateral and contralateral eyes, respectively, and were inhibited by rotation in the opposite direction. H-135i neurons in the left flocculus were excited by counterclockwise rotation about the 135 degrees ipsilateral horizontal axis and were inhibited by clockwise motion. Thus, the VA and H-135i neurons, respectively, encode visual flowfields resulting from head rotations stimulating the ipsilateral horizontal and ipsilateral anterior semicircular canals. 4. Sixty-seven percent of VA and 80% of H-135i neurons had binocular receptive fields, although for most binocular cells the ipsilateral eye was dominant. Binocular stimulation resulted in a greater depth of modulation than did monocular stimulation of the dominant eye for 69% of the cells. 5. Monocular stimulation of the VA neurons revealed that the best axis for the contralateral eye was tilted back 11 degrees, on average, to the best axis for ipsilateral stimulation. For the H-135i neurons, the best axes for monocular stimulation of the two eyes were approximately the same. 6. By stimulating circumscribed portions of the monocular receptive fields of the H-135i neurons with alternating upward and downward largefield motion, it was revealed that the contralateral receptive fields were bipartite. Upward motion was preferred in the anterior 45 degrees of the contralateral field, and downward motion, was preferred in the central 90 degrees of the contralateral visual field.(ABSTRACT TRUNCATED AT 400 WORDS)

Importance of corpus callosum for visual receptive fields of single neurons in cat superior colliculus

1979 ◽  
Vol 42 (1) ◽  
pp. 137-152 ◽  
Author(s):  
A. Antonini ◽  
G. Berlucchi ◽  
C. A. Marzi ◽  
J. M. Sprague
Keyword(s):  
Visual Field ◽  
Corpus Callosum ◽  
Superior Colliculus ◽  
Visual Information ◽  
Visual Learning ◽  
Receptive Fields ◽  
Vertical Meridian ◽  
Retinotectal Projections ◽  
Contralateral Eye ◽  
Stimulation Of

1. Section of the posterior two-thirds of the corpus callosum eliminates almost completely the response of superior colliculus (SC) neurons to stimulation of the contralateral eye in split-chiasm cats. On the contrary, the responsiveness of SC neurons to stimulation of the contralateral eye is not abolished by a transection of the posterior and tectal commissures leaving the corpus callosum intact. The callosal section also reduces the number of SC receptive fields abutting the vertical meridian in the ipsilateral eye of split-chiasm cats. 2. In cats with intact optic pathways, a similar callosal section abolishes the SC representation of the ipsilateral visual field in the ipsilateral eye and also reduces the number of receptive fields adjoining the vertical meridian in the same eye. In the contralateral eye, the SC representation of the ipsilateral visual field is reduced in extension to about one-fifth of that seen in cats with intact commissures. 3. The results suggest that the corpus callosum is the main pathway for cross-midline communication of visual information at not only the cortical, but also the midbrain level. The corpus callosum may subserve this function because it contains uninterrupted crossed corticotectal projections or because it transmits visual information from one hemisphere to contralateral cortical areas projecting ipsilaterally to SC. The latter hypothesis is more likely but, in any case, the findings imply that the lack of interhemispheric transfer of visual learning in cats with a chiasmatic and callosal section may depend on a midline disconnection of both subcortical and cortical visual centers. 4. The corpus callosum is also responsible for the representation of the ipsilateral visual field of the ipsilateral eye in the cat SC. The SC representation of the ipsilateral visual field in the contralateral eye is due, in minimal part, to direct retinotectal connections from temporal retina and, for the largest part, to the corpus callosum. 5. Finally, the corpus callosum contributes to the representation of the contralateral visual field near the vertical meridian of the temporal retina in both split-chiasm and normal cats. This is probably due to the scarcity of direct retinotectal projections from this part of the retina and to their supplementation by corticotectal neurons influenced by the callosal afferents.

Gaze-Stabilizing Deficits and Latent Nystagmus in Monkeys With Early-Onset Visual Deprivation: Role of the Pretectal NOT

2001 ◽  
Vol 86 (2) ◽  
pp. 662-675 ◽  
Author(s):  
Michael J. Mustari ◽  
Ronald J. Tusa ◽  
Andrew F. Burrows ◽  
Albert F. Fuchs ◽  
Christine A. Livingston
Keyword(s):  
Electrical Stimulation ◽  
Visual Motion ◽  
Motor Behavior ◽  
Optic Tract ◽  
Wide Range ◽  
Latent Nystagmus ◽  
Contralateral Eye ◽  
The Right ◽  
Stimulation Of

We studied the role of the pretectal nucleus of the optic tract (NOT) in the development of monocular optokinetic nystagmus (OKN) asymmetries and latent nystagmus (LN) in two monkeys reared with binocular deprivation (BD) caused by binocular eyelid suture for either the first 25 or 55 days of life. Single-unit recordings were performed in the right and left NOT of both monkeys at 2–3 yr of age and compared with similar unit recordings in normally reared monkeys. We also examined ocular motor behavior during electrical stimulation of the NOT and during pharmacological inactivation and activation using GABAA agonists and antagonists. In BD animals a large proportion of NOT units was dominated by the contralateral eye, in striking contrast to normal animals where 100% of NOT units were sensitive to stimuli delivered to either eye. In the 55-day BD animal no binocularly sensitive neurons were found, while in the 25-day BD animal 60% of NOT units retained at least some binocular sensitivity. Differences in direction sensitivity were also observed in BD animals. We found that 56% of units in the 55-day BD monkey and 10% of units in the 25-day BD monkey responded preferentially to contraversive visual motion. In contrast, only 5% of the NOT units encountered in normally reared monkeys respond preferentially during contraversive visual motion, the rest were most sensitive to ipsiversive visual motion. NOT neurons of BD monkeys showed a wide range of speed sensitivities similar to that of normal monkeys. Unilateral electrical stimulation of the NOT in BD animals induced a conjugate nystagmus with slow phases directed toward the side of stimulation. When we blocked the activity of NOT units with muscimol, a potent GABAA agonist, LN was abolished. In contrast, LN was increased when spontaneous activity of the NOT was enhanced with bicuculline, a GABAA antagonist. Our results indicate that the NOT in BD monkeys plays an important role in the OKN deficits and LN generation during monocular viewing. We hypothesize that the large proportion of units dominated by the contralateral eye contribute to the development of monocular OKN asymmetries and LN.

The pupillary light reflex in normal and innate microstrabismic cats, I: Behavior and receptive-field analysis in the nucleus praetectalis olivaris

1989 ◽  
Vol 3 (2) ◽  
pp. 127-138 ◽  
Author(s):  
C. Distler ◽  
K.-P. Hoffmann
Keyword(s):  
Electrical Stimulation ◽  
Discharge Rate ◽  
Binocular Summation ◽  
Light Reflex ◽  
Pupillary Light ◽  
Monocular Stimulation ◽  
Binocular Stimulation ◽  
Pupil Constriction ◽  
Contralateral Eye ◽  
Stimulation Of

AbstractNeurons in the nucleus praetectalis olivaris (NPO) were antidromically identified by electrical stimulation of the nucleus of Edinger-Westphal (EW), the location of preganglionic pupilloconstrictor motoneurons. Electrical stimulation within the NPO leads to bilateral pupil constriction. Single neurons recorded in the NPO respond tonically to light stimuli, and their discharge frequency increases linearly with logarithmic increase in light intensity. This characteristic identifies NPO neurons as luminance detectors. They have large receptive fields mostly lying in the upper and contralateral quadrant of the visual field.Cats with impaired binocular vision show a significantly reduced binocular summation of the pupillary light reflex (BSP), i.e. the increase of pupil constriction during binocular illumination when compared to monocular illumination is less than in normal animals. The investigation of ocular dominance and subthreshold binocular interactions in the NPO of normal and innate microstrabismic cats revealed two possible mechanisms for BSP and its reduction in strabismic subjects. First, the percentage of neurons increasing their discharge rate by illuminating either eye is significantly reduced in the NPO of innate microstrabismic cats (6.6%) when compared to normal cats (22% of all neurons tested). Second, in most NPO neurons of normal cats the subthreshold influence of the ipsilateral eye leads to an increase in neuronal activity during binocular stimulation when compared to monocular stimulation of the contralateral eye (binocular summation). The subthreshold influence of the ipsilateral eye in most NPO neurons of microstrabismic cats, however, is inhibitory, i.e. the neuronal discharge rate during binocular stimulation is decreased when compared to monocular stimulation of the contralateral eye (binocular inhibition). However, there is no significant correlation between BSP and binocularity in the NPO in individual animals. This suggests that BSP may be additionally influenced by visual structures other than NPO.

Direction-selective responses of units in the dorsal terminal nucleus of cat following intravitreal injections of bicuculline

1990 ◽  
Vol 4 (6) ◽  
pp. 605-617 ◽  
Author(s):  
K.L. Grasse ◽  
M. Ariel ◽  
I.D. Smith
Keyword(s):  
Ganglion Cells ◽  
Intravitreal Injections ◽  
Retinal Ganglion ◽  
Optic System ◽  
Accessory Optic System ◽  
Before And After ◽  
Gaba Antagonist ◽  
Contralateral Eye ◽  
First Time ◽  
Stimulation Of

AbstractExtracellular recordings from single units in the dorsal terminal nucleus (DTN) of the cat accessory optic system (AOS) were before and after intravitreal injections of the GABA antagonist bicuculline methiodide (BMI). Direction-selective responses of DTN cells elicited through the contralateral, injected eye were aboloshed 7−12 h following the injection. For the concentrations tested, direction-selective responses through the contralateral (injected) eye did not recover within 26 h. Direction-selective responses through stimulation of the ipsilateral (uninjected) eye were also dramatically depressed for 1−9 h after contralateral eye injections. However, direction-selective responses through the ipsilateral eye eventually returned and were often more vigorous in the final stages. BMI injections into the ipsilateral eye failed to block direction-selective responses through the ipsilateral eye. The effects of intravitreal BMI on contralateral eye responses imply that DTN units receive input from direction-selective retinal ganglion cells. In addition, these results suggest that direction-selective input to the DTN from the visual cortex is independent of the retinal pathway. Using pharmacological methods described here, for the first time direction-selective responses of AOS units driven through the ipsilateral eye can be experimentally isolated.

Responses of cerebral cortex to diffuse monocular and binocular stimulation

1960 ◽  
Vol 198 (1) ◽  
pp. 200-204 ◽  
Author(s):  
B. Delisle Burns ◽  
W. Heron ◽  
Bernice Grafstein
Keyword(s):  
Cerebral Cortex ◽  
Single Unit ◽  
Visual Stimulation ◽  
Constant Ratio ◽  
Monocular Stimulation ◽  
Binocular Stimulation ◽  
Different Types ◽  
Contralateral Eye ◽  
Number Of Discharges ◽  
Stimulation Of

Surface potentials and single unit potentials in the cat's cerebral cortex have been recorded in response to diffuse visual stimulation. Surface responses produced by stimulation of the contralateral eye are larger in amplitude than those produced by stimulation of the ipsilateral eye, while those produced by binocular stimulation are larger still. The amplitude of the surface responses increases to a maximum with increasing intensity of stimulation. For any given single cell, there is a constant ratio between the average number of unit discharges in response to contralateral, ipsilateral and binocular stimulation. At different stimulus intensities this ratio is constant, although the absolute numbers of discharges may be different. It has been possible to divide the cells into functional groups according to a) which eye produces the larger number of discharges, i.e. which eye is ‘dominant’ and b) whether binocular stimulation produces more, fewer, or as many discharges as stimulation of the dominant eye alone. All the functionally different types of neurones may be found in all the cellular layers of the cortex. The latency of the unit responses is shorter with binocular than with monocular stimulation, and is shorter when brighter stimuli are used.

Pharmacological isolation of visual cortical input to the cat accessory optic system: Effects of intravitreal tetrodotoxin on DTN unit responses

1991 ◽  
Vol 6 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Keith L. Grasse
Keyword(s):  
Visual Cortex ◽  
Neural Mechanisms ◽  
Inhibitory Influence ◽  
Optic System ◽  
Accessory Optic System ◽  
Cortical Input ◽  
Before And After ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
Stimulation Of

AbstractDirection-selective responses were recorded from neurons in the dorsal terminal nucleus (DTN) of the cat accessory optic system before and after intravitreal injections of tetrodotoxin (TTX) into the contralateral eye. After approximately 100 min, direction-selective responses driven through stimulation of the contralateral, injected eye were reduced on average by 90%, while direction-selective responses driven through stimulation of the ipsilateral, uninjected eye were not significantly reduced. By 200 min postinjection, ipsilateral direction-selective responses were either equal to or sometimes greater than control values. In the final stages of these experiments (i.e. between 390–830 min after contralateral eye injections), ipsilateral eye responses were on average 30% higher than control. The effects of retinal blockade of the contralateral eye by TTX show that input from the ipsilateral eye alone is sufficient to mediate direction-selective responses in DTN cells. These results and those observed following bicuculline eye injections reported previously (Grasse et al. 1990) demonstrate that direction-selective responses in the DTN driven through stimulation of the contralateral and ipsilateral eyes arise from independent neural mechanisms located in the retina and visual cortex, respectively. Moreover, these findings also suggest that the contralateral eye exerts an inhibitory influence over ipsilateral eye responses which is diminished by TTX injections into the contralateral eye.

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