Opposite Eye Research Articles

The effect of topically applied guanethidine sulphate on pupil and tension responses of the rabbit eye to (−)-adrenaline bitartrate

Five per cent guanethidine sulphate applied topically twice daily for 7 days to one eye of each of a group of eight rabbits produced a significant miosis and hypotension in the treated eyes. The hypotensive effect of 0·25% (−)-adrenaline bitartrate was augmented in the eyes which had received guanethidine and also in the opposite eyes, although mydriatic effect was increased in the guanethidine treated eyes only. Three per cent guanethidine in a similar experiment gave a slight miosis, and significant augmentation of the pupil response to 0·25% adrenaline. It did not significantly alter the tension, or response of tension to adrenaline in either eye. Repeated daily administration of 5% guanethidine plus 0·25% adrenaline initially caused augmented tension and pupil responses to adrenaline, but by day 21 the responses were not greater than controls. These results are compared with published human data.

Activité unitaire corticocérébelleuse et mouvements oculaires: Modifications associées aux saccades du sommeil et de la veille

Single unit activity of vermian oculomotor cortex (Lobules V, VI, VII) and conjugated horizontal rapid eye movements were recorded in the cat, during wakefulness (W) and paradoxical sleep (PS). Correlation between cerebellar and oculomotor events showed the following findings. During PS the units — mostly Purkinje (P) cells — all increased their rate of discharge (mossy fiber activation for P cells) in coincidence with saccadic movements. Two kinds of movement related cells were observed: (i) Most of the units showed an increase of their discharge rate together with occasional bursts. These events were related to magnitude and rate of the saccades without accurate synchronization. (ii) Some cells showed a burst type activation strictly synchronized with the rapid eye movements of sleep. During W, two thirds of the units changed their pattern of discharge (mossy fiber activation for P cells) with waking ocular activity. Modifications of discharge patterns were very different from cells to cells (activation or suppression, increase or decrease in the rate of discharge). Many cells had an accurately synchronized response with the saccades. Some units had a directional reactivity, others gave a similar response for opposite eye movements. P cells showed an increase of their climbing fiber driven activity during PS with eye movements compared with PS without saccades. During PS and W, complex spikes discharges of P cells evidently showed no accurate relation to saccadic eye movements. Functional significations of the above described events are also discussed.

The effect of prostaglandin E 2 on the rhesus monkey pupil

The pupillary constriction (miosis) produced by low doses of PGE 2 may be undetected in primates, even when compared with the opposite (control) eye of the same animal. Experiments on rhesus monkeys reported here demonstrated that the systemic administration of atropine (intravenous) unmasked an otherwise undiscernible pupillary miosis. Three dose levels of PGE 2 were studied (1 μg, 5 μg, and 10 μg). It was determined that 1 μg applied topically (to the cornea) produced no discernible miosis even when atropine was given. At a dose level of 5 μg (topical) no miosis was observed before atropine, but following i.v. administration of atropine a significant miotic effect was unmasked. At 10 μg a small but significant miosis was produced before atropine but was greatly enhanced after atropine. When 1 μg was injected directly into the anterior chamber of the eye a miotic effect was observed which became statistically significant after atropine was given. The application of topical epinephrine did not appear to antagonize the prostaglandin induced miosis.

Neuroectodermal tumor of anterior lip of the optic cup. Glioneuroma transitional to teratoid medullo-epithelioma.

A congenital neoplasm of the inner layer of the anterior lip of the optic cup is delineated. Because of continued growth, local excision was performed at 6 months of age, followed by cardiac arrest. The neoplasm demonstrates features predominantly of a glioneuroma, but with transitions to a teratoid medullo-epithelioma. Local invasion of iris, ciliary body, trabecular meshwork, retina, and sclera was apparent. An associated finding was persistence of the primary vitreous and hyaloid artery in the opposite eye.

An Analysis of Diabetic Retinopathy

Retinopathy was studied in both eyes of 56 diabetics using retinal colour fundal photographs from a minimum of four paired fields in each patient. The Hammersmith Classification of retinopathy was used to assess each field and the results analysed statistically. Comparison of right and left eyes showed a closer symmetry between corresponding retinal fields than between non-corresponding retinal fields of opposite eyes for each of haemorrhages, exudates, new vessels, and venous pathology. Taking all features of retinopathy into account, this symmetrical involvement of opposite eyes applied to all the areas of retina considered. Analysis of the relationships between the various features of diabetic retinopathy suggested that the pathological features fall into two groupings. In the first (type A), new vessel formation and proliferation occur in association with venous pathology with a strong tendency for exudates to be absent. Exudative retinopathy (type B) tends to be a separate condition, whilst haemorrhages form a strong background to both A and B. Careful observation for early detection of new vessels is indicated when there is marked venous pathology or when new vessels are present in the corresponding area of the opposite eye.

Axonal sprouting of ipsilateral optic tract following opposite eye removal.

Axonal sprouting of the ipsilateral retinal projections in the adult rat was evaluated as a consequence of contralateral eye removal. In all experimental animals a generalized axonal sprouting was pre

Diametrically opposed discriminations mediated by a single cerebral hemisphere: effects of further anterior and posterior cortical ablations.

15 pigmented rats with unilateral visual decortications were trained to perform diametrically opposed discriminations mediated by opposite eyes. Further lesions were then placed in anterior cortex or were placed either anteriorly or posteriorly in striate cortex. Performances were unimpaired by anterior lesions, but disruption though incomplete occurred with either type of posterior lesion.

Intrahemispheric mediation of diametrically opposed visual habits.

Of 21 pigmented rats, 13 were surgically restricted to a single cerebral hemisphere and were then sequentially given monocular training on each of 2 diametrically opposed visual pattern discriminations mediated by opposite eyes. 8 served as controls. All but 4 Ss (3 operated and 1 control) were able to learn the opposing discriminations. Acquisition by way of ipsilateral visual pathways was slower than acquisition by way of fibers from the contralateral eye, a finding consistent with known anatomic density of the two optic fiber systems.

A Gamma Ray Probe for the Detection of Ocular Melanomas

A specially designed scintillation probe has been assembled and applied in a promising diagnostic study of malignant melanoma in the human eye. When used in conjunction with a new radiopharmaceutical agent recently developed at The University of Michigan, 125I labeled chloroquine analog, the probe permits simple and nonsurgical gamma ray counting as a substitute for more elaborate techniques required in 32p beta scanning for the same prupose. Preferential uptake of the agent in ocular melanomas has been previously reported using a modified 5-inch NaI (Tl) crystal scanner as the detector. We have realized a substantial improvement in both sensitivity and reproducibility by substituting a hand-held probe placed in contact with the patient's closed eyelid. The counting rate over each eye is followed for a period ranging from 3 to 21 days after dosage. A melanoma in one eye gives rise to an enhanced rate over that eye. Data are presented on a total of 12 patients, including two with confirmed ocular melanomas. In both of these cases, the involved eye consistently shows a significantly greater activity than the opposite eye. In the remaining cases considered negative, measured eye-to-eye asymmtries are much lower, and a measure of the variance associated with these cases is presented.

Aberrant visual projections in the Siamese cat.

Aberrant visual projections in the Siamese cat.

Saccade correlated potentials in optic tectum and cerebellum of Carassius auratus

Summaryo(1)In the encéphale isolé goldfish, Carassius auratus, when recording in the dark adapted state, 50–200 msec after the onset of a conjugate eye saccade, a predominately negative potential, 150–200 msec in duration, with peak amplitudes ranging from 100 to 500 μV, appears over the lateral two-thirds of the optic tectum.(2)Recording at successive depths, the negative wave decreases in amplitude, disappearing at a depth of ∼500–750 μm. A positive going potential emerges at depths of 1000–1250 μm, whose peak corresponds in time to the superficial negative wave peak; it originates in the valvula.(3)Potentials in the optic tectum evoked by saccadic eye movement in the light show shorter latency, more uniform, multiphasic waveform and absence of detectable potentials in the surface to ∼300 μm levels of the tectal layers.(4)Stretch of the abducens eye muscle can produce a 5–10 msec latency, negative going wave in the contralateral tectum. Transection of all eye muscles of the globe reduces the amplitude of TSEP largely in the ipsilateral tectum, without change in waveform or timing. Also, saccadic movements of the opposite eye increase in amplitude.(5)The midline valvula of the cerebellum exhibits a pre-saccadic, positive going 200–600 μV slow wave. High amplitude slow potentials, starting before the saccade, occur 1200 μm beneath the valvula surface.(6)Mechanical distortion of the globe failed to produce any of these phenomena. In the encéphale isolé goldfish, Carassius auratus, when recording in the dark adapted state, 50–200 msec after the onset of a conjugate eye saccade, a predominately negative potential, 150–200 msec in duration, with peak amplitudes ranging from 100 to 500 μV, appears over the lateral two-thirds of the optic tectum. Recording at successive depths, the negative wave decreases in amplitude, disappearing at a depth of ∼500–750 μm. A positive going potential emerges at depths of 1000–1250 μm, whose peak corresponds in time to the superficial negative wave peak; it originates in the valvula. Potentials in the optic tectum evoked by saccadic eye movement in the light show shorter latency, more uniform, multiphasic waveform and absence of detectable potentials in the surface to ∼300 μm levels of the tectal layers. Stretch of the abducens eye muscle can produce a 5–10 msec latency, negative going wave in the contralateral tectum. Transection of all eye muscles of the globe reduces the amplitude of TSEP largely in the ipsilateral tectum, without change in waveform or timing. Also, saccadic movements of the opposite eye increase in amplitude. The midline valvula of the cerebellum exhibits a pre-saccadic, positive going 200–600 μV slow wave. High amplitude slow potentials, starting before the saccade, occur 1200 μm beneath the valvula surface. Mechanical distortion of the globe failed to produce any of these phenomena.

The significance of crossed and uncrossed projections for the acquisition and retrieval of visual engrams in hooded and albino rats.

Occlusion of one eye and functional hemidecortication by cortical spreading depression (CSD) were used to examine the relative importance of crossed and uncrossed visual projections for pattern discrimination learning in hooded and albino rats. Whereas functionally hemidecorticate albino rats were unable to learn in 200 trials a horizontal-vertical discrimination when using the eye contralateral to the depressed hemisphere, hooded rats needed under similar conditions three times as many trials to criterion (167) than when using opposite eye and hemisphere (59). An engram established in intact animals with both eyes could be retrieved in functionally hemidecorticate rats of both strains even with the eye ipsilateral to the intact hemicortex, but retraining required about twice as many trials as when using the contralateral eye. Retrieval of monocularly acquired engrams was less efficient under similar conditions. Pattern discrimination formed through crossed or uncrossed visual projections during monocular occlusion and contralateral or ipsilateral CSD was completely lateralized, since relearning with naive eye and hemisphere proceeded at the same rate as the original learning. On the contrary, a black-white discrimination trained with the eye contralateral to the depressed hemisphere could be partly retrieved by the untrained eye and hemisphere. It is concluded that the ipsilateral visual projection is more effective in hooded than in albino rats and that it can be more efficiently used for retrieval than for acquisition.

Saccade correlated potentials in optic tectum and cerebellum of Carassius auratus

Summary o (1) In the encephale isole goldfish, Carassius auratus , when recording in the dark adapted state, 50–200 msec after the onset of a conjugate eye saccade, a predominately negative potential, 150–200 msec in duration, with peak amplitudes ranging from 100 to 500 μV, appears over the lateral two-thirds of the optic tectum. (2) Recording at successive depths, the negative wave decreases in amplitude, disappearing at a depth of ∼500–750 μm. A positive going potential emerges at depths of 1000–1250 μm, whose peak corresponds in time to the superficial negative wave peak; it originates in the valvula. (3) Potentials in the optic tectum evoked by saccadic eye movement in the light show shorter latency, more uniform, multiphasic waveform and absence of detectable potentials in the surface to ∼300 μm levels of the tectal layers. (4) Stretch of the abducens eye muscle can produce a 5–10 msec latency, negative going wave in the contralateral tectum. Transection of all eye muscles of the globe reduces the amplitude of TSEP largely in the ipsilateral tectum, without change in waveform or timing. Also, saccadic movements of the opposite eye increase in amplitude. (5) The midline valvula of the cerebellum exhibits a pre-saccadic, positive going 200–600 μV slow wave. High amplitude slow potentials, starting before the saccade, occur 1200 μm beneath the valvula surface. (6) Mechanical distortion of the globe failed to produce any of these phenomena.

Connections between wide-field monocular and binocular movement detectors in the brain of a hawk moth

Recordings were made in the brain of Sphinx ligustri of pairs of directionally selective movement detectors, and the spike trains analysed with a computer for possible synaptic connections between two classes of movement detector. (1) Neurones with large binocular fields which arise in the medial protocerebrum and project to the medulla or lobula of one optic lobe, or to the ventral nerve cord. (2) Movement detectors which project from the lobula complex of one optic lobe to the opposite medial protocerebrum. The majority of the second group had back-to-front preferred directions over the ipsilateral eye, and of these many were weakly sensitive to stimuli to the opposite eye. The ipsilateral receptive field covered most of the eye. Optic lobe output cells with the appropriate preferred direction provide a powerful excitatory input to the binocular movement detectors centrifugal to the medulla. Each centrifugal movement detector probably receives excitatory inputs from no more than two optic lobe output cells with back-to-front preferred direction. The same set of optic lobe output neurones probably feeds several cells projecting to the medulla and lobula of both optic lobes, and, possibly, to the ventral nerve cord. Evidence was obtained that the optic lobe output cells themselves receive few excitatory inputs, and that therefore the receptive fields of their input cells are large. Two moving stimuli were presented in different areas of the receptive field. Movement through the null direction in one area inhibited the response to movement in the preferred direction in another area. This suppression was stronger in optic lobe output cells with front-to-back preferred direction than in units with back-to-front preferred direction. Thus the optic lobe output cells, or wide-field units feeding them, receive inhibitory inputs from wide-field units with the opposite preferred direction. Similar tests in which moving stimuli were presented to both eyes gave results indicating that the binocular centrifugal movement detectors may receive inhibitory inputs from movement detectors with back-to-front preferred direction. The possible functional significance of these inhibitory inputs is discussed.

Interhemisphere imitation in split-brain monkeys

Three experienced split-brain monkeys were taught a visual pattern discrimination in one eye hemisphere. After several hundred over-learning trials, the opposite untrained eye hemisphere was allowed to observe 40 perfect trials. Subsequently, ten test trials in which every response was reinforced were delivered exclusively to the untrained hemisphere. Two monkeys performed perfectly while another required 40 additional observation trials before a perfect score was realized. The results are consistent with the view that errors during acquisition training need not be a necessary condition for visual discrimination learning and suggest that learning through observation may be more efficient than trial and error learning in some situations.

Correlation Between Ocular Inflammation and Antibody Production

Abstract Rabbits were immunized intravitreally, intravenously, or intradermally with small amounts of protein antigen. Intravitreal immunization resulted in the development of uveitis associated with serum antibody production. Intravenous injection of the same amount of antigen was ineffective in this case, and intradermal injection was effective only if antigen was incorporated with Freund's complete adjuvant. Intravitreally immunized animals were challenged at various times by a second intravitreal injection into the opposite eye. Even when antibody had fallen to undetectable levels, these rabbits showed a rapid onset of uveitis and an accelerated antibody response. Animals primarily immunized by the intravenous route or by the subcutaneous route also exhibited an accelerated response following intravitreal challenge into the eye. Intravenous challenge with small amounts of antigen caused a rapid rise in antibody titer in rabbits that had received a primary intravitreal injection in the right eye. However, contrary to the results obtained by others who have used higher challenge doses, uveitis did not recur in the right eyes of these animals. The results of these investigations are discussed in relation to the X, Y, Z scheme of cell differentiation for immunologically competent cells.

Correlation Between Ocular Inflammation and Antibody Production

Abstract Rabbits were immunized by the intravitreal injection of BGG in the right eye and were killed 12 days later. Cell suspensions were made from uveal tract tissue and assayed for plaque production by a modification of the Jerne technique. Cells from the injected right eyes produced from 300 to 800 plaques/million cells. Cells from the left eyes, which had received only buffer, failed to produce plaques. In other experiments, rabbits were reinjected intravitreally in the opposite (left) eye at various times after primary immunization. The left eye cells produced more than 800 plaques/million cells. Cells from the right eyes were still capable of producing smaller numbers of plaques even though no inflammation had recurred. Examination of sections of uveal tract tissue revealed pyroninophilic cells in eyes that formed antibody. These observations confirm the hypothesis that ocular tissue can actually be involved in antibody formation, and that under certain conditions the eye can act as an “accessory lymph node.”

Neural limitations of visual excitability. IX. Monocular and interocular changes of sensitivity during flicker stimulation.

Changes of threshold luminance for a test flash (Ft) were studied as a function of temporal displacement between two conditioning flashes (Fc1 and Fc2), viewed with either the tested eye (monocular stimulation) or the homologous retinal location in the opposite eye (interocular stimulation). Under both conditions, the threshold was elevated most near the beginning of Fc1, fell to a minimum between flashes, and rose again to a secondary maximum near the beginning of Fc2. The form of this function changed dramatically as the Fc1–Fc2 interval decreased, the greatest effect being obtained with interocular stimulation. When a train of conditioning flashes (Fc1–Fc5) at or near fusion frequency was utilized, temporal oscillations of threshold luminance were detectable with monocular but not with interocular stimulation.

Foveal critical flicker frequency as influenced by intermittent stimulation of the opposite eye at various locations.

Foveal critical flicker frequency as influenced by intermittent stimulation of the opposite eye at various locations.

Evaluation of the Bielschowsky head-tilt test.

Tilting of the head as an aid in diagnosis of paretic vertical muscles is based on the theory that torsional action of the vertical muscles maintains the vertical meridians of the eyes erect when the head is tilted to the side. Since rotation of the optic disc about the macula occurs in the same direction, approximately to the same degree as the head is tilted, torsion as a normal function of the vertical ocular muscles is challenged. In differentiating between paresis of a superior oblique muscle or the superior rectus of the opposite eye, since paresis of either muscle in diagnostic problem cases will usually demonstrate a positive test for both muscles, tilting of the head as a diagnostic procedure is unreliable and often misleading.