276 research outputs found

    Visual prostheses based on Silicon PhotoMultiplier: The SPEye project

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    Some genetically based degenerative illnesses of retina cause total or partial blindness in ‚ąľ 1‚ąē4000 people totaling ‚ąľ 1.5 million visually impaired. No cure is available and the only chance of improved vision is a visual prosthesis replacing the damaged retina. Some projects have delivered interesting but still not fully satisfactory results in the last 20 years. An innovative approach based on subretinic implant of SiPM exploiting its internal amplification is presented. Progress in implementing this approach is presented

    An Implantable System for Neural Communication and Stimulation: Design and Implementation

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    Assistive technologies enable humans to enhance their abilities and restore missing or lost physiological functions. However, some pathologies, such as facial palsy, are currently treated only with invasive surgical procedures. This article introduces a novel bio-compatible and safe implantable engineered based system for neural communication and stimulation, which is able to overcome facial paralysis due to a nerve lesion by highly reducing the need of surgeries. The proposed system design leverages on ultra-low power intra-body communication technologies to forward a signal extracted from a healthy nerve towards the injured contralater one. Preliminary prototypes are described to assess the feasibility of the proposed solution and the design of the overall communication system. Technical challenges that may be faced in the implementation of the system are discussed. The proposed solution opens the way to new opportunities for realizing innovative systems that employ unconventional communication technologies to support healthcare applications, with particular focus on neurological diseases therapies

    Measurable fractional spin for quantum Hall quasiparticles on the disk

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    International audienceWe study the spin of the localized quasiparticle excitations of lowest-Landau-level quantum Hall states defined on a disk. The spin that we propose satisfies the spin-statistics relation and can be used to reconstruct the topological geometric phase associated to the exchange of two arbitrarily chosen quasiparticles. Since it is related to the quadrupole moment of the quasiparticle charge distribution, it can be measured in an experiment and could reveal anyonic properties in a way that is complementary to the interferometric schemes employed so far. We first discuss our definition for the quasiholes of the Laughlin state, for which we present a numerical and analytical study of our spin, and we proceed with a discussion of several kinds of quasiholes of the Halperin 221 state. Finally, we discuss the link between our spin and the adiabatic rotation of the quasiparticles around their axis and demonstrate that our spin obeys the spin-statistics relation

    In vitro-derived medium spiny neurons recapitulate human striatal development and complexity at single-cell resolution

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    Stem cell engineering of striatal medium spiny neurons (MSNs) is a promising strategy to understand diseases affecting the striatum and for cell-replacement therapies in different neurological diseases. Protocols to generate cells from human pluripotent stem cells (PSCs) are scarce and how well they recapitulate the endogenous fetal cells remains poorly understood. We have developed a protocol that modulates cell seeding density and exposure to specific morphogens that generates authentic and functional D1- and D2-MSNs with a high degree of reproducibility in 25 days of differentiation. Single-cell RNA sequencing (scRNA-seq) shows that our cells can mimic the cell-fate acquisition steps observed in vivo in terms of cell type composition, gene expression, and signaling pathways. Finally, by modulating the midkine pathway we show that we can increase the yield of MSNs. We expect that this protocol will help decode pathogenesis factors in striatal diseases and eventually facilitate cell-replacement therapies for Huntington's disease (HD)

    Affective components in promoting physical activity: A randomized controlled trial of message framing

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    Although the study of the affective components involved in predicting physical activity is spreading faster and faster, there is a lack of studies testing their role when promoting physical activity through message interventions. In the present study, we considered these components by focusing on how anticipated affective reactions and emotional processing of the messages influence receivers‚Äô affective attitude toward physical activity, concurrent behavior, and future intention. A sample of 250 participants was involved in an intervention relying on prefactual (i.e., ‚ÄúIf ‚Ķ then‚Ķ‚ÄĚ) messages promoting physical activity. All messages were sent through a research app and were focused on the expected consequences of exercising (or not exercising). Four experimental conditions involving messages differing as to their outcome sensitivity framing (i.e., gain, non-loss, non-gain, and loss) were compared to a control condition. Results showed that reading gain and non-gain messages enhanced the positive affective attitude toward physical activity, compared to control. Enhanced affective attitude after the intervention increased, in turn, self-reported physical activity and future intention. Interestingly, gain messages were even more persuasive for people with a low level of positive anticipated affective reactions. Furthermore, their effectiveness was especially attributable to the elicitation of hope in receivers. Discussion focuses on the advantages of considering affective components and their implications when promoting physical activity

    SREBP2 gene therapy targeting striatal astrocytes ameliorates Huntington's disease phenotypes

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    Brain cholesterol is produced mainly by astrocytes and is important for neuronal function. Its biosynthesis is severely reduced in mouse models of Huntington's disease. One possible mechanism is a diminished nuclear translocation of the transcription factor sterol regulatory element-binding protein 2 (SREBP2) and, consequently, reduced activation of SREBP2-controlled genes in the cholesterol biosynthesis pathway. Here we evaluated the efficacy of a gene therapy based on the unilateral intra-striatal injection of a recombinant adeno-associated virus 2/5 (AAV2/5) targeting astrocytes specifically and carrying the transcriptionally active N-terminal fragment of human SREBP2 (hSREBP2). Robust hSREBP2 expression in striatal glial cells in R6/2 Huntington's disease mice activated the transcription of cholesterol biosynthesis pathway genes, restored synaptic transmission, reversed dopamine receptor D2 (Drd2) transcript levels decline, cleared mutant huntingtin aggregates and attenuated behavioural deficits. We conclude that glial SREBP2 participates in Huntington's disease brain pathogenesis in vivo and that AAV-based delivery of SREBP2 to astrocytes counteracts key features of the disease

    K+ accumulation and clearance in the calyx synaptic cleft of type I mouse vestibular hair cells

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    Vestibular organs of Amniotes contain two types of sensory cells, named Type I and Type II hair cells. While Type II hair cells are contacted by several small bouton nerve terminals, Type I hair cells receive a giant terminal, called a calyx, which encloses their basolateral membrane almost completely. Both hair cell types release glutamate, which depolarizes the afferent terminal by binding to AMPA post-synaptic receptors. However, there is evidence that non-vesicular signal transmission also occurs at the Type I hair cell-calyx synapse, possibly involving direct depolarization of the calyx by K+ exiting the hair cell. To better investigate this aspect, we performed whole-cell patch-clamp recordings from mouse Type I hair cells or their associated calyx. We found that [K+] in the calyceal synaptic cleft is elevated at rest relative to the interstitial (extracellular) solution and can increase or decrease during hair cell depolarization or repolarization, respectively. The change in [K+] was primarily driven by GK,L, the low-voltage-activated, non-inactivating K+ conductance specifically expressed by Type I hair cells. Simple diffusion of K+ between the cleft and the extracellular compartment appeared substantially restricted by the calyx inner membrane, with the ion channels and active transporters playing a crucial role in regulating intercellular [K+]. Calyx recordings were consistent with K+ leaving the synaptic cleft through postsynaptic voltage-gated K+ channels involving KV1 and KV7 subunits. The above scenario is consistent with direct depolarization and hyperpolarization of the calyx membrane potential by intercellular K+
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