Corticobasal degeneration (CBD) is a neurodegenerative condition characterized by 4R tau protein deposition in several brain regions that clinically manifests itself as a heterogeneous atypical ...parkinsonism typically expressed in adulthood. The prototypical clinical phenotype of CBD is corticobasal syndrome (CBS). Important insights into the pathophysiological mechanisms underlying motor and higher cortical symptoms in CBS have been gained by using advanced neuroimaging and neurophysiological techniques. Structural and functional neuroimaging studies often show asymmetric cortical and subcortical abnormalities, mainly involving perirolandic and parietal regions and basal ganglia structures. Neurophysiological investigations including electroencephalography and somatosensory evoked potentials provide useful information on the origin of myoclonus and on cortical sensory loss. Transcranial magnetic stimulation demonstrates heterogeneous and asymmetric changes in the excitability and plasticity of primary motor cortex and abnormal hemispheric connectivity. Neuroimaging and neurophysiological abnormalities in multiple brain areas reflect asymmetric neurodegeneration, leading to asymmetric motor and higher cortical symptoms in CBS.
Annealing a film of CsPbBr3 nanocrystals (NCs) leads to the removal of surface ligands and ripening of the NCs below 200 degree C. This results in a reduced photoluminescence quantum yield due to the ...formation of trap states while on the other hand the conductive properties of the films are stabilized, with a significantly stronger photocurrent after annealing.
Colloidal nanocrystals attract considerable attention in the field of light emitting devices thanks to their high fluorescence quantum yield, low amplified spontaneous emission (ASE) threshold, and ...spectral tunability
electronic structure engineering and surface functionalization. Combining polymer microcavities with colloidal nanocrystals as gain material promises a solution-based fabrication route to plastic laser cavities as well as applications in the field of smart flexible large area light sources and sensors. Here we demonstrate lasing from polymer microcavities embedding solution processable dot-in-rod (DiR) CdSe/CdS nanocrystals. Two highly reflective polymer dielectric mirrors are prepared by spin-coating of alternated layers of polyacrylic acid and poly(
-vinyl carbazole), with their photonic band gap tailored to the emission of the DiRs. The DiRs are enclosed in the polymer microcavity by drop-cast deposition on one mirror, followed by pressing the mirrors onto each other. We obtain excellent overlap of the ASE band of the DiRs with the photonic band gap of the cavity and observe optically pumped lasing at 640 nm with a threshold of about 50 μJ cm
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Gilles de la Tourette syndrome (GTS) is characterized by motor and vocal tics and often associated with obsessive–compulsive disorder (OCD). Responses to intermittent/continuous theta-burst ...stimulation (iTBS/cTBS), which probe long-term potentiation (LTP)-/depression (LTD)-like plasticity in the primary motor cortex (M1), are reduced in GTS. ITBS-/cTBS-induced M1 plasticity can be affected by brain-derived neurotrophic factor (BDNF) polymorphism. We investigated whether the BDNF polymorphism influences iTBS-/cTBS-induced LTP-/LTD-like M1 plasticity in 50 GTS patients and in 50 age- and sex-matched healthy subjects. In GTS patients, motor and psychiatric (OCD) symptom severity was rated using the Yale Global Tic Severity Scale (YGTSS) and the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS). We compared M1 iTBS-/cTBS-induced plasticity in healthy subjects and in patients with GTS. We also compared responses to TBS according to BDNF polymorphism (Val/Val vs Met carriers) in patients and controls. Fourteen healthy subjects and 13 GTS patients were Met carriers. When considering the whole group of controls, as expected, iTBS increased whereas cTBS decreased MEPs. Differently, iTBS/cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS. When comparing responses to TBS according to BDNF polymorphism, in healthy subjects, Met carriers showed reduced MEP changes compared with Val/Val individuals. Conversely, in patients with GTS, responses to iTBS/cTBS were comparable in Val/Val individuals and Met carriers. YGTSS and Y-BOCS scores were comparable in Met carriers and in Val/Val subjects. We conclude that iTBS and cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS, and this was not affected by BDNF genotype.
In healthy subjects (HS), transcranial magnetic stimulation (TMS) applied during ‘linguistic’ tasks discloses excitability changes in the dominant hemisphere primary motor cortex (M1). We ...investigated ‘linguistic’ task‐related cortical excitability modulation in patients with adductor‐type spasmodic dysphonia (ASD), a speech‐related focal dystonia. We studied 10 ASD patients and 10 HS. Speech examination included voice cepstral analysis. We investigated the dominant/non‐dominant M1 excitability at baseline, during ‘linguistic’ (reading aloud/silent reading/producing simple phonation) and ‘non‐linguistic’ tasks (looking at non‐letter strings/producing oral movements). Motor evoked potentials (MEPs) were recorded from the contralateral hand muscles. We measured the cortical silent period (CSP) length and tested MEPs in HS and patients performing the ‘linguistic’ tasks with different voice intensities. We also examined MEPs in HS and ASD during hand‐related ‘action‐verb’ observation. Patients were studied under and not‐under botulinum neurotoxin‐type A (BoNT‐A). In HS, TMS over the dominant M1 elicited larger MEPs during ‘reading aloud’ than during the other ‘linguistic’/‘non‐linguistic’ tasks. Conversely, in ASD, TMS over the dominant M1 elicited increased‐amplitude MEPs during ‘reading aloud’ and ‘syllabic phonation’ tasks. CSP length was shorter in ASD than in HS and remained unchanged in both groups performing ‘linguistic’/‘non‐linguistic’ tasks. In HS and ASD, ‘linguistic’ task‐related excitability changes were present regardless of the different voice intensities. During hand‐related ‘action‐verb’ observation, MEPs decreased in HS, whereas in ASD they increased. In ASD, BoNT‐A improved speech, as demonstrated by cepstral analysis and restored the TMS abnormalities. ASD reflects dominant hemisphere excitability changes related to ‘linguistic’ tasks; BoNT‐A returns these excitability changes to normal.
In healthy subjects, magnetic stimulation over dominant primary motor area elicited larger MEPs during loud reading compared to other linguistic and non linguistic tasks, while in spasmodic dysphonia (ASD) it elicited MEPs of increased amplitude also during syllabic phonation. In ASD, BoNT‐A improved speech as demonstrated by cepstral analysis and restored the TMS abnormalities. We conclude that spasmodic dysphonia is characterized by abnormal dominant speech‐related network activation.
Abstract Introduction Tremor is frequently associated with dystonia, but its pathophysiology is still unclear. Dysfunctions of cerebellar circuits are known to play a role in the pathophysiology of ...action-induced tremors, and cerebellar impairment has frequently been associated to dystonia. However, a link between dystonic tremor and cerebellar abnormalities has not been demonstrated so far. Methods Twenty-five patients with idiopathic isolated cervical dystonia, with and without tremor, were enrolled. We studied the excitability of inhibitory circuits in the brainstem by measuring the R2 blink reflex recovery cycle (BRC) and implicit learning mediated by the cerebellum by means of eyeblink classical conditioning (EBCC). Results were compared with those obtained in a group of age-matched healthy subjects (HS). Results Statistical analysis did not disclose any significant clinical differences among dystonic patients with and without tremor. Patients with dystonia (regardless of the presence of tremor) showed decreased inhibition of R2 blink reflex by conditioning pulses compared with HS. Patients with dystonic tremor showed a decreased number of conditioned responses in the EBCC paradigm compared to HS and dystonic patients without tremor. Conclusion The present data show that cerebellar impairment segregates with the presence of tremor in patients with dystonia, suggesting that the cerebellum might have a role in the occurrence of dystonic tremor.
•Children with CLDs have a similar susceptibility to SARS-CoV-2 infection, regardless of the underlying etiology of liver disease.•Children with chronic liver disease (CLD) and suspected or confirmed ...COVID-19 present with mild symptoms, or may be even asymptomatic, similarly to the general pediatric population.•Chronic liver disease likely does not represent an additional risk factor for severe disease course of COVID-19.
Abstract Background In Parkinson's disease (PD), the influence of chronic pain on motor features has never been investigated. We have recently designed a technique that combines nociceptive system ...activation by laser stimuli and primary motor cortex (M1) activation through transcranial magnetic stimulation (TMS), in a laser-paired associative stimulation design (Laser-PAS). In controls, Laser-PAS induces long-term changes in motor evoked potentials reflecting M1 long-term potentiation-like plasticity, arising from pain-motor integration. Objective We here examined the possible influence of chronic pain on motor responses to Laser-PAS in patients with PD, with and without chronic pain. Methods We compared motor responses to Laser-PAS in healthy subjects and in patients with PD, with and without chronic pain. Results Unlike controls, we found reduced responses to Laser-PAS in patients with PD, with and without pain. Patients off and on dopaminergic therapy had similar responses to Laser-PAS. When comparing responses to Laser-PAS in patients with and without pain, the two patients' subgroups had similar abnormalities. When we compared patients with pain in the body region investigated with Laser-PAS, with those with pain in other body regions, we found prominent changes in patients with homotopic pain. Finally, when comparing Laser-PAS with the original PAS protocol, which combines electric peripheral nerve stimuli and TMS, in patients without pain and those with homotopic pain, we found similar responses to both techniques in patients without pain, whereas Laser-PAS induced greater abnormalities than PAS in patients with pain. Conclusions In PD, chronic pain degrades response to Laser-PAS through abnormal pain-motor integration.
Responsive monolayers are key building blocks for future applications in organic and molecular electronics in particular because they hold potential for tuning the physico-chemical properties of ...interfaces, including their energetics. Here we study a photochromic SAM based on a conjugated azobenzene derivative and its influence on the gold work function (Φ(Au)) when chemisorbed on its surface. In particular we show that the Φ(Au) can be modulated with external stimuli by controlling the azobenzene trans/cis isomerization process. This phenomenon is characterized experimentally by four different techniques, kelvin probe, kelvin probe force microscopy, electroabsorption spectroscopy and ultraviolet photoelectron spectroscopy. The use of different techniques implies exposing the SAM to different measurement conditions and different preparation methods, which, remarkably, do not alter the observed work function change (Φ(trans)-Φ(cis)). Theoretical calculations provided a complementary insight crucial to attain a deeper knowledge on the origin of the work function photo-modulation.
In healthy humans, the execution of linguistic tasks modifies the excitability of the hand area of the dominant primary motor cortex (M1), as tested by TMS. Our aim was to investigate the effect of ...linguistic tasks on the excitability of the M1 in patients with adductor type-spasmodic dysphonia (ASD), before and after Botulinum Neurotoxin Type A (BoNT-A) injections. We studied 10 patients with ASD and 10 age-matched healthy subjects. All participants were right handed. The excitability of either M1 hand area was evaluated at the baseline and during different linguistic and non-linguistic tasks: (1) reading aloud of single words; (2) silent reading; (3) looking at meaningless non-letter strings; (4) oral movements without vocalization; (5) producing simple syllabic phonation. In healthy controls, the motor evoked potential (MEP) elicited by TMS of the dominant M1 were significantly larger during reading aloud. In ASD patients, MEP enhancement in the dominant hand emerged not only during reading aloud but also during syllabic phonation. BoNT-A injections restored the neurophysiologic abnormalities. We conclude that ASD is characterized by an abnormal excitability of the hand area of the dominant M1 during specific linguistic tasks. This likely reflects an altered functional connectivity between cortical speech network and M1.
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