Optic Perineuritis in an Asymptomatic SARS-CoV-2 Infection.

Introduction: Optic perineuritis (OPN) is a previously undescribed sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here we present a case of OPN that developed several weeks after initial confirmation of the presence of novel coronavirus RNA in the nasopharynx by polymerase chain reaction assay and subsequent confirmation of SARS-CoV-2 IgG seropositivity in the absence of other systemic inflammatory or infectious markers.

Case Report: An asymptomatic 71-year-old man with noninsulin-dependent diabetes mellitus (NIDDM) tested RNA positive for SARS-CoV-2 during a routine screening of patients at a skilled nursing facility.

Vergence neurons identified in the rostral superior colliculus code smooth eye movements in 3D space.

The rostral superior colliculus (rSC) encodes position errors for multiple types of eye movements, including microsaccades, small saccades, smooth pursuit, and fixation. Here we address whether the rSC contributes to the development of neural signals that are suitable for controlling vergence eye movements. We use both single-unit recording and microstimulation techniques in monkey to answer this question.

Neuronal evidence for individual eye control in the primate cMRF.

Previous single unit recordings and electrical stimulation have suggested that separate regions of the MRF participate in the control of vergence and conjugate eye movements. Neurons in the supraoculomotor area (SOA) have been found to encode symmetric vergence [Zhang, Y. et al.

Anatomical evidence for interconnections between the central mesencephalic reticular formation and cervical spinal cord in the cat and macaque.

A gaze-related region in the caudal midbrain tegementum, termed the central mesencephalic reticular formation (cMRF), has been designated on electrophysiological grounds in monkeys. In macaques, the cMRF correlates with an area in which reticulotectal neurons overlap with tectoreticular terminals. We examined whether a region with the same anatomical characteristics exists in cats by injecting biotinylated dextran amine into their superior colliculi.

Comparison of saccade-associated neuronal activity in the primate central mesencephalic and paramedian pontine reticular formations.

The oculomotor system must convert signals representing the target of an intended eye movement into appropriate input to drive the individual extraocular muscles. Neural models propose that this transformation may involve either a decomposition of the intended eye displacement signal into horizontal and vertical components or an implicit process whereby component signals do not predominate until the level of the motor neurons. Thus decomposition models predict that premotor neurons should primarily encode component signals while implicit models predict encoding of off-cardinal optimal directions by premotor neurons.

Neurones associated with saccade metrics in the monkey central mesencephalic reticular formation.

Neurones in the central mesencephalic reticular formation (cMRF) begin to discharge prior to saccades. These long lead burst neurones interact with major oculomotor centres including the superior colliculus (SC) and the paramedian pontine reticular formation (PPRF). Three different functions have been proposed for neurones in the cMRF: (1) to carry eye velocity signals that provide efference copy information to the SC (feedback), (2) to provide duration signals from the omnipause neurones to the SC (feedback), or (3) to participate in the transformation from the spatial encoding of a target selection signal in the SC into the temporal pattern of discharge used to drive the excitatory burst neurones in the pons (feed-forward).

Eye movements evoked by electrical microstimulation of the mesencephalic reticular formation in goldfish.

Anatomical studies in goldfish show that the tectofugal axons provide a large number of boutons within the mesencephalic reticular formation. Electrical stimulation, reversible inactivation and cell recording in the primate central mesencephalic reticular formation have suggested that it participates in the control of rapid eye movements (saccades). Moreover, the role of this tecto-recipient area in the generation of saccadic eye movements in fish is unknown.

Spatial characteristics of neurons in the central mesencephalic reticular formation (cMRF) of head-unrestrained monkeys.

Prior studies of the central portion of the mesencephalic reticular formation (cMRF) have shown that in head-restrained monkeys, neurons discharge prior to saccades. Here, we provide a systematic analysis of the patterns of activity in cMRF neurons during head unrestrained gaze shifts. Two types of cMRF neurons were found: presaccadic neurons began to discharge before the onset of gaze movements, while postsaccadic neurons began to discharge after gaze shift onset and typically after the end of the gaze shift.

Temporal characteristics of neurons in the central mesencephalic reticular formation of head unrestrained monkeys.

The accompanying paper demonstrated two distinct types of central mesencephalic reticular formation (cMRF) neuron that discharged before or after the gaze movement: pre-saccadic or post-saccadic. The movement fields of pre-saccadic neurons were most closely associated with gaze displacement. The movement fields of post-saccadic neurons were most closely associated with head displacement.

Molecular cloning and expression profiling of optineurin in the rhesus monkey.

Purpose: It has been shown that mutations in the optineurin (OPTN) gene are involved in the etiology of adult-onset primary open-angle glaucoma (POAG). In view of close similarities between human and nonhuman primate ocular development and function, the rhesus monkey is considered a suitable model for human visual system research. Therefore, this study was conducted to clone the orthologue of the human OPTN gene in the rhesus monkey (Rh-OPTN) and to determine its genomic organization.

Treatment of recalcitrant idiopathic orbital inflammation (chronic orbital myositis) with infliximab.

Purpose: To report results of treatment with a monoclonal antibody (infliximab) directed against tumor necrosis factor alpha in seven patients with chronic and difficult-to-control idiopathic orbital inflammation (orbital myositis).

Design: Observational case series.

Methods: Retrospective data were collected from seven patients who had idiopathic orbital inflammation and who were evaluated at three medical centers.

Contribution of the superior colliculus and the mesencephalic reticular formation to gaze control.

Converging lines of evidence support a role for the intermediate and deep layers of the superior colliculus (SC) and the mesencephalic reticular formation (MRF) in the control of combined head and eye movements (i.e., gaze).

Effects of reversible inactivation of the primate mesencephalic reticular formation. II. Hypometric vertical saccades.

Electrical microstimulation and single-unit recording have suggested that a group of long-lead burst neurons (LLBNs) in the mesencephalic reticular formation (MRF) just lateral to the interstitial nucleus of Cajal (INC) (the peri-INC MRF, piMRF) may play a role in the generation of vertical rapid eye movements. Inactivation of this region with muscimol (a GABA(A) agonist) rapidly produced vertical saccade hypometria (6 injections). In three of six injections, there was a marked reduction in the velocity of vertical saccades out of proportion to saccade amplitude (i.

Effects of reversible inactivation of the primate mesencephalic reticular formation. I. Hypermetric goal-directed saccades.

Single-neuron recording and electrical microstimulation suggest three roles for the mesencephalic reticular formation (MRF) in oculomotor control: 1) saccade triggering, 2) computation of the horizontal component of saccade amplitude (a feed-forward function), and 3) feedback of an eye velocity signal from the paramedian zone of the pontine reticular formation (PPRF) to higher structures. These ideas were tested using reversible inactivation of the MRF with pressure microinjection of muscimol, a GABA(A) agonist, in four rhesus monkeys prepared for chronic single-neuron and eye movement recording. Reversible inactivation revealed two subregions of the MRF: ventral-caudal and rostral.

Chiasmal herniation as a complication of bromocriptine therapy.

Introduction: Medical treatment of macroprolactinomas with dopamine agonists decreases tumor mass and improves visual defects. We report an unusual complication of a macroprolactinoma responding to bromocriptine: a visual field defect caused by downward herniation of the optic chiasm.

Materials And Methods: A 64-year-old woman was found to have a 4.

Diagnostic neuroimaging: computed tomography and magnetic resonance imaging.

Background: Computed tomography (CT) and magnetic resonance imaging (MR) are commonly used neuroimaging modalities for patients with signs or symptoms of neuro-ophthalmic disorders. Understanding the technology and clinical uses of these modalities is vital in patient management.

Methods/results: Basic instrument design and technology are presented together with a discussion of indications and contraindications to the use of these imaging techniques.

Activity of neurons in monkey superior colliculus during interrupted saccades.

1. Recent studies of the monkey superior colliculus (SC) have identified several types of cells in the intermediate layers (including burst, buildup, and fixation neurons) and the sequence of changes in their activity during the generation of saccadic eye movements. On the basis of these observations, several hypotheses about the organization of the SC leading to saccade generation have placed the SC in a feedback loop controlling the amplitude and direction of the impending saccade.

Central mesencephalic reticular formation (cMRF) neurons discharging before and during eye movements.

1. One hundred twenty neurons were recorded in the central mesencephalic reticular formation (cMRF) of four rhesus monkeys, trained to make visually guided and targeted saccadic eye movements. Eye movements were recorded with the head fixed, using electrooculography (EOG) or subconjunctival scleral search coils.

Superior colliculus neurons mediate the dynamic characteristics of saccades.

1. The locus of activity within the superior colliculus (SC) is related to the desired displacement of the eye. Current hypotheses suggest that the location of this locus of activity determines the amplitude of the saccade and that the level of activity at this locus determines eye velocity.

Superior colliculus neurons provide the saccadic motor error signal.

Studies of the intermediate layers of the superior colliculus have suggested that it provides a desired change in eye position signal (delta E) for the generation of saccadic eye movements. Recent evidence, however, has shown that some neurons in these layers may be related to the velocity of saccades. We present single cell recordings from the intermediate layers of monkey superior colliculus that are consistent with the hypothesis that many superior colliculus neurons provide instead a motor error signal, em.

Cortical activity blockade prevents ocular dominance plasticity in the kitten visual cortex.

Recordings from single units in kitten primary visual cortex show that a reversible blockade of the discharge activities of cortical neurons and geniculocortical afferent terminals by intracortical infusion of the sodium channel blocker tetrodotoxin (TTX) completely prevented the ocular dominance shift that would normally be seen after monocular deprivation. The blockade of cortical plasticity, like the blockade of discharge activity, was reversible, and plasticity was restored following recovery from the effects of TTX. These results extend previous work suggesting involvement of electrical activity at the level of the cortex in the phenomenon of cortical plasticity by demonstrating an absolute requirement for discharge activities in the primary visual cortex.