Correlation of tau pathology in eye movement related brainstem nuclei in cases of progressive supranuclear palsy (PSP) and a proposed role of perineuronal nets

2016 ◽  
Vol 127 (3) ◽  
pp. e2
Author(s):  
A. Horn ◽  
A. Fröschl ◽  
J. Feige ◽  
S. Röber ◽  
H. Kretzschmar
2021 ◽  
Author(s):  
Wei Siang Lee ◽  
Daniel CS Tan ◽  
Yuanyuan Deng ◽  
Annika van Hummel ◽  
Stefania Ippati ◽  
...  

Tau pathology initiates in defined brain regions and is known to spread along neuronal connections as symptoms progress in Alzheimer’s disease (AD) and other tauopathies. This spread requires the release of tau from donor cells, but the underlying molecular mechanisms remained unknown. Here, we established the interactome of the C-terminal tail region of tau and identified syntaxin 8 (STX8) as a mediator of tau release from cells. Similarly, we showed the syntaxin 6 (STX6), part of the same SNARE family as STX8 also facilitated tau release. STX6 was previously genetically linked to progressive supranuclear palsy (PSP), a tauopathy. Finally, we demonstrated that the transmembrane domain of STX6 is required and sufficient to mediate tau secretion. The differential role of STX6 and STX8 in alternative secretory pathways suggests association of tau with different secretory processes. Taken together, both syntaxins, STX6 and STX8, may contribute to AD and PSP pathogenesis by mediating release of tau from cells and facilitating pathology spreading.


2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.


Perception ◽  
1972 ◽  
Vol 1 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Nicole Lesèvre ◽  
A Rémond

Experiments are reported the aim of which was to elucidate the cause of each of the components of the lambda response, and particularly to evaluate the role of ‘on’ and ‘off’ visual effects which appear at various times during the oculomotor process and also the possible influence of non-visual mechanisms. Eight subjects with normal sight were studied under the following conditions: (i) horizontal eye movements of 12° were guided by fixation points placed on a dimly-lit uniform black field of 20°; a checkerboard of 6° aperture was placed in this field so as to be integrated into the oculomotor process at different times—at the beginning, during and at the end of the eye movement; (ii) successive horizontal eye movements of 3°, 7° and 11° scanned a checkerboard of 20°, each square of which had a 40′ aperture; (iii) the checkerboard was moved with an amplitude and period similar to those of the eye movements in (ii), but this time with gaze fixed. Horizontal and vertical movements of both eyes were recorded with an EOG. An EEG of the parieto-occipital regions was obtained using eight linked bipolar derivations in line on two montages, median longitudinal and right-left transverse. The EEG and EOG data were digitalized and a numerical programme of waveform recognition was used to identify the beginning of the saccade which triggers the averaging out of the EEG before (100 ms) and after (500 ms) the eye movement. A discussion of the results, taking into account the latency of the different components and their reinforcements or inhibition depending on experimental conditions, suggests that the two initial components of lambda response (including the initial portion of the classical lambda wave) might be due to visual effects (‘off effect’) that arise at the start of the movement or slightly before it at the time that the saccadic suppression begins. The later components could be attributed to visual effects brought into play towards the end of the movement (‘on effect’), when perception becomes normal again. It is, however, difficult to explain some of the results related to the amplitude of lambda components without bringing in a mechanism of non-visual origin (corollary discharge).


Author(s):  
George David Perkin ◽  
Andrew John Lees ◽  
Gerald Malcolm Stern ◽  
Roman Stefan Kocen

SUMMARY:Five patients with progressive supranuclear palsy are described, in whom the ophthalmoplegia developed late in the course of the disease. In two, an internuclear component was identified in the ophthalmoplegia, and one patient had an alternating nystagmus of a type not previously described in this condition.The late appearance of the ophthalmoplegia, with a corresponding delay in establishing the diagnosis, is compared to the similar experience of Pfaffenbach et al (1972) in six patients.Other clinical features, previously seldom described, have been encountered. Dysphasia was seen in two cases, both of whom had evidence of cortical atrophy on neuro-radiological investigation. The evidence that cortical changes, in particular the presence of neurofibrillary tangles, may be a specific morphological characteristic of the disease rather than a chance association is discussed. Disorders of respiratory rhythm in four patients were similar to those described by Mastaglia et al. (1973), and indistinguishable from those occurring after encephalitis lethargica.A review of cases resembling progressive supranuclear palsy in the early part of the century fails to show any with post-encephalitic features, nor does a search of reviews of eye movement disorders in encephalitis lethargica and post-encephalitic Parkinsonism provide comparable cases. None of the forty patients with post encephalitic Parkinsonism examined at the Highlands Hospital had a clinical picture resembling progressive supranuclear palsy.It is suggested that neither on clinical nor pathological grounds is it justifiable to equate this disorder with known postencephalitic syndromes.


2018 ◽  
Vol 80 (7) ◽  
pp. 1691-1704 ◽  
Author(s):  
Aoife Mahon ◽  
Alasdair D. F. Clarke ◽  
Amelia R. Hunt

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