151 research outputs found

    Molecular characterisation of childhood craniopharyngioma and identification and testing of novel drug targets

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    BACKGROUND: Adamantinomatous Craniopharyngiomas (ACPs) are clinically challenging sellar region tumours, known to be characterised by mutations in CTNNB1. ACPs are often histologically complex, with different morphological cell types and surrounded by a florid glial reaction. Murine models have been generated through activating β-catenin and support a critical role for nucleo-cytoplasmic accumulating β-catenin cell clusters (‘clusters’) in driving tumorigenesis. AIMS: To phenotype in detail the 3D growth patterns of human and murine ACP; To characterise the genomic and transcriptomic landscape of human and murine ACP, including of clusters; To characterise therapeutically targetable molecular pathways and perform pre-clinical therapeutic trials. METHODS: Human ACP samples underwent micro-focus-CT scanning, whole genome sequencing, targeted next generation sequencing and RNA sequencing, both with, and without, laser capture microdissection. The growth dynamics of murine ACP was characterised by serial MRI and a cohort of murine ACPs, at various stages, underwent RNA and exome sequencing. A pre-clinical murine trial using a Sonic Hedgehog (SHH) pathway inhibitor was performed. RESULTS: CTNNB1 mutationsin human ACP were confirmed as clonal within tumour epithelia. Gene expression signatures corresponding to tumour epithelia, reactive glia and immune infiltrate were derived and novel ACP genes were identified (e.g. BCL11B). A relationship between human and murine ACPs with the developing tooth was also established, in particular the similarity of clusters to the enamel knot. Further molecular dissection identified a complex interplay between tumour cell compartments demonstrating a role for paracrine signalling. Inhibition of the SHH pathway in the pre-clinical murine trial resulted in a decrease in median survival from 33 weeks to 11.9 weeks (p=0.048). A signature of inflammasome activation in ACP was also identified in solid and cystic components of ACP. CONCLUSIONS: ACPs have clonal mutations in CTNNB1 and exhibit complex signalling interplay between different cell compartments. Expression analysis reveals a new molecular paradigm for understanding ACP tumorigenesis as an aberrant copycat of natural tooth development, with inflammation driven by activation of inflammasomes. Caution is recommended in the use of SHH pathway inhibitors in patients with ACP

    Transmission of Predictable Sensory Signals to the Cerebellum via Climbing Fiber Pathways Is Gated during Exploratory Behavior

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    International audiencePathways arising from the periphery that target the inferior olive [spino-olivocerebellar pathways (SOCPs)] are a vital source of information to the cerebellum and are modulated (gated) during active movements. This limits their ability to forward signals to climbing fibers in the cerebellar cortex. We tested the hypothesis that the temporal pattern of gating is related to the predictability of a sensory signal. Low-intensity electrical stimulation of the ipsilateral hindlimb in awake rats evoked field potentials in the C1 zone in the copula pyramidis of the cerebellar cortex. Responses had an onset latency of 12.5 +/- 0.3 ms and were either short or long duration (8.7 +/- 0.1 vs 31.2 +/- 0.3 ms, respectively). Both types of response were shown to be mainly climbing fiber in origin and therefore evoked by transmission in hindlimb SOCPs. Changes in response size (area of field, millivolts per millisecond) were used to monitor differences in transmission during rest and three phases of rearing: phase 1, rearing up; phase 2, upright; and phase 3, rearing down. Responses evoked during phase 2 were similar in size to rest but were smaller during phases 1 and 3, i.e., transmission was reduced during active movement when self-generated (predictable) sensory signals from the hindlimbs are likely to occur. To test whether the pattern of gating was related to the predictability of the sensory signal, some animals received the hindlimb stimulation only during phase 2. Over similar to 10 d, the responses became progressively smaller in size, consistent with gating-out transmission of predictable sensory signals relayed via SOCPs

    Electrophysiological Mapping of Novel Prefrontal – Cerebellar Pathways

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    Whilst the cerebellum is predominantly considered a sensorimotor control structure, accumulating evidence suggests that it may also subserve non-motor functions during cognition. However, this possibility is not universally accepted, not least because the nature and pattern of links between higher cortical structures and the cerebellum are poorly characterized. We have therefore used in vivo electrophysiological methods in anaesthetized rats to directly investigate connectivity between the medial prefrontal cortex (prelimbic subdivision, PrL) and the cerebellum. Stimulation of deep layers of PrL evoked distinct field potentials in the cerebellar cortex with a mean latency to peak of approximately 35 ms. These responses showed a well-defined topography, and were maximal in lobule VII of the contralateral vermis (a known oculomotor centre); they were not attenuated by local anaesthesia of the overlying M2 motor cortex, though M2 stimulation did evoke field potentials in lobule VII with a shorter latency (approximately 30 ms). Single unit recordings showed that prelimbic cortical stimulation elicits complex spikes in lobule VII Purkinje cells, indicating transmission via a previously undescribed cerebro-olivocerebellar pathway. Our results therefore establish a physiological basis for communication between PrL and the cerebellum. The role(s) of this pathway remain to be resolved, but presumably relate to control of eye movements and/or distributed networks associated with integrated prefrontal cortical functions

    Pre-movement changes in sensorimotor beta oscillations predict motor adaptation drive

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    International audienceBeta frequency oscillations in scalp electroencephalography (EEG) recordings over the primary motor cortex have been associated with the preparation and execution of voluntary movements. Here, we test whether changes in beta frequency are related to the preparation of adapted movements in human, and whether such effects generalise to other species (cat). Eleven healthy adult humans performed a joystick visuomotor adaptation task. Beta (15-25 Hz) scalp EEG signals recorded over the motor cortex during a pre-movement preparatory phase were, on average, significantly reduced in amplitude during early adaptation trials compared to baseline, late adaptation, or aftereffect trials. The changes in beta were not related to measurements of reaction time or reach duration. We also recorded local field potential (LFP) activity within the primary motor cortex of three cats during a prism visuomotor adaptation task. Analysis of these signals revealed similar reductions in motor cortical LFP beta frequencies during early adaptation. This effect was present when controlling for any influence of the reaction time and reach duration. Overall, the results are consistent with a reduction in pre-movement beta oscillations predicting an increase in adaptive drive in upcoming task performance when motor errors are largest in magnitude and the rate of adaptation is greatest

    Non-invasive Stimulation of the Cerebellum in Health and Disease

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    The cerebellum is linked to motor, cognitive and affective functions. Anatomically, the cerebellum is part of an interconnected network including a wide range of other brain structures. This chapter reviews ways in which non-invasive stimulation has been used to activate or inhibit these circuits and how this has contributed to our understanding of cerebellar function in both motor and non-motor domains. The utility of non-invasive stimulation of the cerebellum in the treatment of neurological and psychiatric diseases (Parkinson’s disease, cerebellar ataxia, stroke, depression and schizophrenia) is discussed. The chapter concludes with consideration of the challenges that must be overcome if non-invasive cerebellar stimulation is to be adopted in a wider clinical setting

    PENGEMBANGAN JOBSHEET TRAINER PLC SEBAGAI SUMBER PEMBELAJARAN PRAKTIKUM OTOMASI INDUSTRI

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    Penelitian ini bertujuan untuk mengembangkan sebuah media pembelajaran sebagai sumber belajar mahasiswa berupa jobsheet praktikum Otomasi Industri. Selain itu, penelitian ini bertujuan untuk mengetahui kelayakan dari jobsheet yang telah dikembangkan serta melihat hasil implementasi jobsheet setelah digunakan oleh para mahasiswa. Penelitian ini dirasa perlu dilakukan untuk membuat sebuah sumber belajar yang layak serta dapat memberikan manfaat lebih khususnya mahasiswa Elektronika Indsutri. Metodologi yang digunakan oleh penulis pada penelitian ini menggunakan penelitian campuran dengan model rancangan campuran sekuensial eksploratori, menggunakan pendekatan penelitian dan pengembangan (Research and Development). Berdasarkan hasil penelitian yang telah dilakukan didapatkan hasil bahwa jobsheet trainer PLC Phoenix Contact ILC 130/131 Starterkit telah dikembangkan sesuai tahapan penelitian dan layak digunakan serta dapat diimplementasikan dalam praktikum Otomasi Industri.---This study aims to develop learning media as a source of students learning in form of practical Industrial Automation jobsheet. Besides, this study aims to prove the feasibility of jobsheet that has been developed and the result of jobsheet implementation by students. This study is considered important to create a decent learning resource and provide benefits, especially for Electronics Industries Students, Department of Electrical Engineering Education, Faculty of Technology and Vocational Skills Education. The methodology used by the authors in this study is mixed research model with exploratory sequences, using a research and development approach (research and development). Based on study results, trainer jobsheet of PLC Phoenix Contact ILC 130/131 Starterkit feasible to be used and can be implemented in practice Industrial Automation

    Sensorimotor, language, and working memory representation within the human cerebellum

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    The cerebellum is involved in a wide range of behaviours. A key organisational principle from animal studies is that somatotopically corresponding sensory input and motor output reside in the same cerebellar cortical areas. However, compelling evidence for a similar arrangement in humans and whether it extends to cognitive functions is lacking. To address this, we applied cerebellar optimised whole-brain functional MRI in 20 healthy subjects. To assess spatial overlap within the sensorimotor and cognitive domains, we recorded activity to a sensory stimulus (vibrotactile) and a motor task; the Sternberg verbal working memory (VWM) task; and a verb generation paradigm. Consistent with animal data, sensory and motor activity overlapped with a somatotopic arrangement in ipsilateral areas of the anterior and posterior cerebellum. During the maintenance phase of the Sternberg task, a positive linear relationship between VWM load and activity was observed in right Lobule VI, extending into Crus I bilaterally. Articulatory movement gave rise to bilateral activity in medial Lobule VI. A conjunction of two independent language tasks localised activity during verb generation in right Lobule VI-Crus I, which overlapped with activity during VWM. These results demonstrate spatial compartmentalisation of sensorimotor and cognitive function in the human cerebellum, with each area involved in more than one aspect of a given behaviour, consistent with an integrative function. Sensorimotor localisation was uniform across individuals, but the representation of cognitive tasks was more variable, highlighting the importance of individual scans for mapping higher order functions within the cerebellum

    Structural basis of cerebellar microcircuits in the rat

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    The topography of the cerebellar cortex is described by at least three different maps, with the basic units of each map termed “microzones,” “patches,” and “bands.” These are defined, respectively, by different patterns of climbing fiber input, mossy fiber input, and Purkinje cell (PC) phenotype. Based on embryological development, the “one-map” hypothesis proposes that the basic units of each map align in the adult animal and the aim of the present study was to test this possibility. In barbiturate anesthetized adult rats, nanoinjections of bidirectional tracer (Retrobeads and biotinylated dextran amine) were made into somatotopically identified regions within the hindlimb C1 zone in copula pyramidis. Injection sites were mapped relative to PC bands defined by the molecular marker zebrin II and were correlated with the pattern of retrograde cell labeling within the inferior olive and in the basilar pontine nuclei to determine connectivity of microzones and patches, respectively, and also with the distributions of biotinylated dextran amine-labeled PC terminals in the cerebellar nuclei. Zebrin bands were found to be related to both climbing fiber and mossy fiber inputs and also to cortical representation of different parts of the ipsilateral hindpaw, indicating a precise spatial organization within cerebellar microcircuitry. This precise connectivity extends to PC terminal fields in the cerebellar nuclei and olivonuclear projections. These findings strongly support the one-map hypothesis and suggest that, at the microcircuit level of resolution, the cerebellar cortex has a common plan of spatial organization for major inputs, outputs, and PC phenotype
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