Acute Hemorrhagic Leukoencephalitis with Concurrent Retinal Vasculitis in an Elderly Japanese Patient: A Case Report.

A 68-year-old Japanese man developed a fever, headache, hiccups, and altered consciousness. Brain magnetic resonance imaging (MRI) revealed a hemorrhagic lesion in the right temporal lobe and multiple high-intensity white matter lesions. A brain biopsy showed pathological findings consistent with acute disseminated encephalomyelitis (ADEM), suggesting a diagnosis of acute hemorrhagic leukoencephalitis (AHLE), an aggressive ADEM variant. The patient also developed myodesopsia and was diagnosed with retinal vasculitis, likely due to a hyperimmune state caused by AHLE. Corticosteroids enabled full recovery. Although AHLE is uncommon in elderly individuals, clinicians should be aware of its occurrence in this patient subgroup and recognize potential retinal manifestations associated with AHLE.

No-go neurons in the cerebellar oculomotor vermis and caudal fastigial nuclei: planning tracking eye movements.

The cerebellar dorsal vermis lobules VI-VII (oculomotor vermis) and its output region (caudal fastigial nuclei, cFN) are involved in tracking eye movements consisting of both smooth-pursuit and saccades, yet, the exact role of these regions in the control of tracking eye movements is still unclear. We compared the neuronal discharge of these cerebellar regions using a memory-based, smooth-pursuit task that distinguishes discharge related to movement preparation and execution from the discharge related to the processing of visual motion signals or their memory. Monkeys were required to pursue (i.e., go), or not pursue (i.e., no-go) in a cued direction, based on the memory of visual motion direction and go/no-go instructions. Most (>60 %) of task-related vermal Purkinje cells (P-cells) and cFN neurons discharged specifically during the memory period following no-go instructions; their discharge was correlated with memory of no-go instructions but was unrelated to eye movements per se during the action period of go trials. The latencies of no-go discharge of vermal P-cells and cFN neurons were similar, but were significantly longer than those of supplementary eye field (SEF) no-go neurons during an identical task. Movement-preparation signals were found in ~30 % of smooth-pursuit-related neurons in these cerebellar regions and some of them also carried visual memory signals. Our results suggest that no-go neurons are a newly revealed class of neurons, detected using the memory-based pursuit task, in the oculomotor vermis-cFN pathway and that this pathway contributes specifically to planning requiring the working memory of no-go instructions and preparation of tracking eye movements.

Neuronal activity in medial superior temporal area (MST) during memory-based smooth pursuit eye movements in monkeys.

We examined recently neuronal substrates for predictive pursuit using a memory-based smooth pursuit task that distinguishes the discharge related to memory of visual motion-direction from that related to movement preparation. We found that the supplementary eye fields (SEF) contain separate signals coding memory and assessment of visual motion-direction, decision not-to-pursue, and preparation for pursuit. Since medial superior temporal area (MST) is essential for visual motion processing and projects to SEF, we examined whether MST carried similar signals. We analyzed the discharge of 108 MSTd neurons responding to visual motion stimuli. The majority (69/108 = 64%) were also modulated during smooth pursuit. However, in nearly all (104/108 = 96%) of the MSTd neurons tested, there was no significant discharge modulation during the delay periods that required memory of visual motion-direction or preparation for smooth pursuit or not-to-pursue. Only 4 neurons of the 108 (4%) exhibited significantly higher discharge rates during the delay periods; however, their responses were non-directional and not instruction specific. Representative signals in the MSTd clearly differed from those in the SEF during memory-based smooth pursuit. MSTd neurons are unlikely to provide signals for memory of visual motion-direction or preparation for smooth pursuit eye movements.

Oscillatory eye movements resembling pendular nystagmus in normal juvenile macaques.

PURPOSE: Juvenile monkeys being trained on smooth-pursuit tasks exhibit ocular oscillations resembling pendular nystagmus. The purpose of this study was to analyze these oscillations, the effects of gabapentin on them, and responses of cerebellar floccular neurons to understand possible neuronal mechanisms. METHODS: Four monkeys were trained for horizontal and vertical smooth pursuit; in two, saccades were also tested. Frequency, peak-to-peak eye velocity, and amplitude of the ocular oscillations were measured. In one monkey, the effect of gabapentin on the oscillations was measured, and oscillation-related neuronal discharge was recorded in the cerebellar floccular region. RESULTS: Ocular oscillations, with features of pendular nystagmus, appeared early during training of both horizontal and vertical pursuit in all four monkeys. Although these oscillations were observed both in the direction of pursuit and orthogonally, the velocity and amplitude of oscillation were larger in the direction of pursuit, implicating pursuit mechanisms in their generation. Corrective saccades were often superimposed on the oscillations during pursuit and fixation. Gabapentin suppressed oscillations in the monkey tested. Recordings in the floccular region revealed a subset of neurons discharged during both the oscillations and corrective saccades. Many of them exhibited burst-tonic discharge during visually guided saccades, similar to discharge of brain stem burst-tonic neurons, suggesting contributions of the neural integrator to the oscillations. CONCLUSIONS: The developmentally transient ocular oscillations occurring in monkeys during pursuit training has properties resembling pendular nystagmus. Both smooth pursuit and a neural integrator may contribute to these ocular oscillations. Analysis using an efference-copy pursuit model supports the interpretation herein.

Neuronal activity in the caudal frontal eye fields of monkeys during memory-based smooth pursuit eye movements: comparison with the supplementary eye fields.

Recently, we examined the neuronal substrate of predictive pursuit during memory-based smooth pursuit and found that supplementary eye fields (SEFs) contain signals coding assessment and memory of visual motion direction, decision not-to-pursue ("no-go"), and preparation for pursuit. To determine whether these signals were unique to the SEF, we examined the discharge of 185 task-related neurons in the caudal frontal eye fields (FEFs) in 2 macaques. Visual motion memory and no-go signals were also present in the caudal FEF but compared with those in the SEF, the percentage of neurons coding these signals was significantly lower. In particular, unlike SEF neurons, directional visual motion responses of caudal FEF neurons decayed exponentially. In contrast, the percentage of neurons coding directional pursuit eye movements was significantly higher in the caudal FEF than in the SEF. Unlike SEF inactivation, muscimol injection into the caudal FEF did not induce direction errors or no-go errors but decreased eye velocity during pursuit causing an inability to compensate for the response delays during sinusoidal pursuit. These results indicate significant differences between the 2 regions in the signals represented and in the effects of chemical inactivation suggesting that the caudal FEF is primarily involved in generating motor commands for smooth-pursuit eye movements.

Arteritic anterior ischemic optic neuropathy with positive myeloperoxidase antineutrophil cytoplasmic antibody.

BACKGROUND: Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is related to smallvessel vasculitis. There have been some reports of optic nerve involvements with increased values of MPO-ANCA. We report two cases of anterior ischemic optic neuropathy (AION) in which ANCA-associated vasculitis was suspected to be responsible for the pathogenesis. CASES: A 66-year-old man and a 72-year-old man had ocular symptoms of AION in both eyes with positive MPO-ANCA. OBSERVATIONS: Both patients showed high erythrocyte sedimentation rate, C-reactive protein, and MPOANCA values at first. Temporal artery biopsies were negative for temporal arteritis, whereas small-vessel vasculitis was found only in the latter patient. Visual dysfunctions remained unchanged after steroid pulse therapy, although laboratory data returned to normal levels after the treatment. Fluorescein angiography revealed selective occlusion of capillaries, arterioles, and precapillaries in the retina and choroid as well as in the optic disc. CONCLUSIONS: The identical characteristics of the angiographic findings of both eyes in the two cases indicated that the obliteration of small vessels in the intraocular arterial system was closely related to MPO-ANCA-associated vasculitis.

Memory and decision making in the frontal cortex during visual motion processing for smooth pursuit eye movements.

Cortical motor areas are thought to contribute "higher-order processing," but what that processing might include is unknown. Previous studies of the smooth pursuit-related discharge of supplementary eye field (SEF) neurons have not distinguished activity associated with the preparation for pursuit from discharge related to processing or memory of the target motion signals. Using a memory-based task designed to separate these components, we show that the SEF contains signals coding retinal image-slip-velocity, memory, and assessment of visual motion direction, the decision of whether to pursue, and the preparation for pursuit eye movements. Bilateral muscimol injection into SEF resulted in directional errors in smooth pursuit, errors of whether to pursue, and impairment of initial correct eye movements. These results suggest an important role for the SEF in memory and assessment of visual motion direction and the programming of appropriate pursuit eye movements.