Morris B. Bender

XVI Eye Movements from Semicircular Canal Nerve Stimulation in the Cat

Al though the eye movements induced by semicircular canal st imulation have been k n o w n for m a n y years, there have been few reports of the activity evoked in the eye muscles by single semicircular canals. Szentagothai in agreement wi th Hogyes found t ha t s t imulaxad t ion of a single canal in dogs wi th an appropr ia te endolymphat ic cu r ren t produced eye muscle act ivi ty in one ipsilateral and one cont ra xad lateral eye muscle.^-** F luu r s t imulated the ampul la ry nerves of precoUicularly transected cats and described two pa t te rns of oculomoxad tor activity.^ Electric s t imulat ion of a single anter ior canal nerve usually resulted in conjugate eye movements u p w a r d , one posterior canal in conjugate eye movements d o w n w a r d , and one lateral canal nerve in conjugate horizontal deviations. In about oneth i rd of his experiments disconjugate movements were observed which were simxad ilar to those described by Szentagothai in dogs.^^^^ U t s u m i polarized each ampulla in rabbits and produced still another pa t t e rn of disconxad jugate movements .

COMPENSATORY EYE MOVEMENTS INDUCED BY VERTICAL SEMICIRCULAR CANAL STIMULATION.

Abstract Electric stimulation of single anterior or posterior semicircular canal nerves induced disconjugate eye movements in monkey, cat, dog and rabbit. These movements were different but characteristic for each canal nerve stimulated in each species. This is in contrast to eye movements evoked by lateral canal nerve stimulation which were conjugate and horizontal in these species. We investigated the relationship of these disconjugate eye movements to acceleratory head rotations in the plane of the vertical canals. Ocular deviations were calculated which would oppose head rotations in several vertical planes. The axes for these rotations lay at 45°, 90° and 0° from the midsagittal plane of the head and were parallel to the plane of the lateral canals. These rotations corresponded to head movements which would have excited single anterior or posterior canals, bilateral anterior or posterior canals, or unilateral anterior and posterior canals respectively. The eye movements evoked by vertical semicircular canal nerve stimulation appeared to be the same as the eye movements which were predicted to oppose rotation in the planes of these semicircular canals. Eye movements from single anterior canal nerve stimulation which appeared disconjugate from the front of the animal were associated when viewed from the plane of rotation of the head. These data show that the degree of ocular dissociation and the direction of the eye movements can be mathematically approximated if the plane of the excited semicircular canal and the angle of the optic axis of the animal are known. The most important factor in determining the form of the induced eye movements from species to species is the lateral or frontal positioning of the eyes in the head. The results also show that the central neural organization which produces these movements must vary from species to species to provide the precise ocular compensation in direction which exists for acceleratory head rotation.

Nystagmus Induced by Electric Stimulation of Ampullary Nerves

This investigation was supported by Research Grant NB-00294 from the National Institute of Neurological Diseases and Blindness. Dr. Suzuki was the recipient of a Fulbright Scholarship and was supported in part by grants from the Dazian and Abramson Foundations. We should like to acknowledge the help of Dr. Kazuyoshi Goto in one of the experiments presented, the technical assistance of Mr. Edward Murray, and helpful criticism of Drs. Julius Korein and Sidney Diamond during the course of this work.Ampullary nerves were electrically stimulated with square waves in alert or lightly sleeping cats. This stimulus bypassed the ampullary receptor and permitted study of the response of the central vestibulo-oculomotor system to step increases in ampullary nerve frequency. In these animals such stimulation induced typical jerky nystagmus. The pattern of nystagmus was characteristic for each canal nerve stimulated. When two or more canals were simultaneously stimulated, the nystagmus from individual canals summated a...

Optokinetic afternystagmus in the monkey.

Abstract Optokinetic nystagmus and its afternystagmus was studied by recording of corneo-retinal potential with the electroencephalograph. This technique registers eye movements in light and dark, binocularly and uniocularly, with the eyes opened or closed, and does not interfere with the field of vision or the range of eye movement. Optokinetic afternystagmus is readily elicited from the monkey provided it is examined in darkness. The direction of these eye movements is determined by the antecedent optokinetic stimulus. The frequency and duration are only partially determined by this stimulus. Optokinetic afternystagmus is diminished and in time obliterated by light, but it may be brought out again by returning the animal to darkness thereby demonstrating that light merely makes the phenomenon latent and does not abolish it. This after response is suppressed by eyelid closure and sleep and can be reestablished by waking the animal. These observations may be analyzed in many ways, e.g. figure-ground relationships of the stimulus, the effect of sleep on eye movements, proprioceptive mechanisms, internuncial neuronal pools of reciprocating forces, but a definitive mechanism has yet to be worked out.

‘Lightning eye movements’ (ocular myoclonus) ☆

Abstract 1. (1) Three patients showing rapid bursts of horizontal to-and-fro eye movements were studied. 2. (2) The burst pattern consisted of small conjugate saccades. 3. (3) Bursts most often occurred following horizontal gaze movements toward the more paretic or ataxic side of the patients body, and the first movement of each burst was most often toward the less paretic side. 4. (4) All three of the patients showed some signs of dysfunction in the pontine paramedian zone; 2 of the 3 patients also showed evidence of pretectal lesions, and in both these patients the burst eye movements appeared to be closely associated with eye movements characteristic of pretectal dysfunction. 5. (5) Several other peculiarities of ocular movements, which may in some way be related to the ‘lightning eye movements’, were noted in both patients with predominant pretectal involvement.

Recovery of the electro-oculogram after total ablation of the retina in monkeys.

Abstract 1. 1. Electrical (RC and DC) recordings of predictable ocular movements, such as calorically induced nystagmus and passive pulling under anesthesia, were obtained from monkeys before and after removal of the cornea, retina and choroid and placement of an intrascleral plastic implant. 2. 2. Immediately after surgery the EOG of nystagmus was flat for 2–3 days. Thereafter it recovered progressively and approached normal amplitude 2–4 weeks later. Passive eye movements between the extreme right and left positions produced a 1 mV deflection both in the normal monkey and in the same animal about one month after eye evisceration. 3. 3. These results indicate that the EOG and consequently the bioelectric field of the eye on which it depends, may recover to normal values after total excision of the contents of the globe. Findings raise questions regarding the relative contribution of extraretinal mechanisms in the origin of the resting potential of the eye.

Vertical gaze: Clinical and experimental considerations with particular reference to oblique movements

On correlating the clinicopathologic data in man with those in the experimental monkey one may conclude that the syndrome of paralysis of upward gaze is due to involvement of the mesencephalon, while the syndrome of paralysis of downward gaze is due to implication of a more rostral area in the diencephalon. In instances of paralysis of both upward and downward gaze the pathology is at the mesodiencephalic junction. Paralysis of downward gaze is rarely associated with impairment of pupillary reflexes, whereas paralysis of upward gaze is frequently accompanied by impairments of efferent pupillary responses, eyelid retraction and, less frequently, by binocular adductive saccades. In man, paralysis of upward gaze is commonly caused by lesions, such as tumor, vascular disease or aqueductal stenosis, localized within the mesodiencephalon. Isolated paralysis of downward gaze is rare in cases of tumor and found predominately in patients with vascular disease. In patients with diffuse involvement of the brain, suc...

AFTER-IMAGERY IN DEFECTIVE FIELDS OF VISION

In a study of visual after-images of patients with homonymous hemianopia one would anticipate an after-image only in that part of the field which is perceived by the patient during fixation. Fuchs (1920, 1921), however, found that such patients saw more in the after-image than in the stimulus field or the perceived field of vision. Thus Fuchs noted that a figure only partly seen on fixation (the remainder of the figure was not seen because it was situated in the blind part of the field) was perceived by the same patient in its entirety in the afterimage. This is known as the phenomenon of completion.t Using simple figures, such as circles and squares, Fuchs postulated that completion depended on the inner structural requirements of the stimulus figures. On the other hand, Bender and Teuber (1946), who also studied completion effects in impaired fields of vision, and used complex figures such as an American flag in complementary colours, believed that these effects need not necessarily be explained only by qualities of the stimulus figure. They observed that the after-image may represent only partial tendencies toward completion. Thus additional areas seen in the after-image or the completed areas did not always produce a smoothing of contours or the completion of a total figure. Sometimes there occurred in the afterimage irregular additions to that which was perceived in the stimulus field. The present investigation was undertaken to study the nature of after-image alterations in a patient with irregular but homonymous defects in the-fields of vision following lesions in both occipital lobes. The test patterns used were simple geometric figures.

PERCEPTUAL PATTERNS DURING RECOVERY FROM GENERAL ANAESTHESIA

In a series of previous communications the examination of cutaneous sensation by the method of double simultaneous stimulation has been described (Bender and Furlow, 1944 and 1945; Bender, 1945; Bender and Teuber, 1946; Bender, 1948). When double rather than single stimulation is employed, the phenomena of extinction, obscuration, and displacement make their appearance. In these phenomena one of the two simultaneously applied stimuli is either not perceived at all (extinction), perceived as diminished in intensity (obscuration), or perceived as localized to a part of the body other than that stimulated (displacement) (Bender, 1951). Furthermore, these phenomena do not occur in a haphazard fashion. A repeatedly observed and predictable pattern of perception has been described in cutaneous testing by double simultaneous stimulation. Thus it is possible to predict which of the two stimuli will be accurately perceived, and which will be extinguished, obscured, or displaced. The accurately perceived stimulus has been termed the dominant one. After numerous studies of different parts of the body with double simultaneous stimulation, a pattern of dominance has been described. The face is most dominant, the hand is least dominant, and other body areas lie in a predictable order of dominance between the face and hand (Bender, Shapiro, and Schappel, 1949). These phenomena and patterns of dominance were first described in patients with disease of the brain and spinal cord. They were later found to be a prominent feature of the response of normal children to double simultaneous stimulation (Bender, Fink, and Green, 1950). The normal adult may make errors on the first few trials of double simultaneous stimulation, provided the subject is not previously acquainted with the test and is given no preliminary instructions other than the command.

Sensitized Pupillary Dilator and Facial Muscles as Indicators of Sympathetic and Parasympathetic Substances in Blood.

Summary (1) A preparation is described in which sympathomimetic and parasympathomimetic substances could be detected in the blood. (2) Any discharge of either or both of these substances under various physiologic states was indicated by dilatation of the denervated pupil or by contraction in the facial muscles respectively. (3) Under emotional stress, the cat exhibited predominantly sympathetic activity while the monkey showed parasympathetic activity in their denervated structures. (4) The denervated facial muscles were used as indicators of end points in the determinations of rates of hydrolysis by sera and cerebrospinal fluids.