Are Dutch Skylarks partial migrants? Ring recovery data and radio-telemetry suggest local coexistence of contrasting migration strategies

In recent years, Skylarks Alauda arvensis have undergone dramatic population declines in many European countries. Evidence exists for deteriorating conditions during the breeding season, but little is known about the situation during the rest of the annual cycle. Here we use two approaches to test if the Dutch breeding population of Skylarks consists of resident and/or migratory individuals. First, we present an analysis of ring recoveries from the Dutch Ringing Centre "Vogeltrekstation". Out of 25 recoveries, 12 Skylarks were resident in winter, 10 migrated and three were classified as probable migrants. Resident birds were accompanied during winter by birds from northern and eastern Europe. Very limited natal and breeding dispersal recorded in the same dataset suggests that our results were not influenced by long dispersal distances. Next, we compared these results to a local radio-telemetry study in the northern Netherlands. During two different years we equipped a total of 27 Skylarks from a breeding population with radio-transmitters and followed them during the subsequent winter. Four birds were found to winter locally. Out of 23 individuals that we did not find in winter, 14 returned in the following breeding season to the study area, all with a working transmitter, suggesting that they wintered outside our study area. Two ring recoveries of birds from the same study population indeed showed migration to south-west Europe. Based on these two lines of evidence, we conclude local coexistence of a resident and a migrant strategy in Dutch Skylarks. The findings of our study are important for the planning of conservation efforts, as we can only protect this rapidly declining species when we know their behaviour and whereabouts throughout the entire annual cycle

Phase of beta-frequency tACS over primary motor cortex modulates corticospinal excitability

The assessment of corticospinal excitability by means of transcranial magnetic stimulation-induced motor evoked potentials is an established diagnostic tool in neurophysiology and a widely used procedure in fundamental brain research. However, concern about low reliability of these measures has grown recently. One possible cause of high variability of MEPs under identical acquisition conditions could be the influence of oscillatory neuronal activity on corticospinal excitability. Based on research showing that transcranial alternating current stimulation can entrain neuronal oscillations we here test whether alpha or beta frequency tACS can influence corticospinal excitability in a phase-dependent manner. We applied tACS at individually calibrated alpha- and beta-band oscillation frequencies, or we applied sham tACS. Simultaneous single TMS pulses time locked to eight equidistant phases of the ongoing tACS signal evoked MEPs. To evaluate offline effects of stimulation frequency, MEP amplitudes were measured before and after tACS. To evaluate whether tACS influences MEP amplitude, we fitted one-cycle sinusoids to the average MEPs elicited at the different phase conditions of each tACS frequency. We found no frequency-specific offline effects of tACS. However, beta-frequency tACS modulation of MEPs was phase-dependent. Post hoc analyses suggested that this effect was specific to participants with low (<19 Hz) intrinsic beta frequency. In conclusion, by showing that beta tACS influences MEP amplitude in a phase-dependent manner, our results support a potential role attributed to neuronal oscillations in regulating corticospinal excitability. Moreover, our findings may be useful for the development of TMS protocols that improve the reliability of MEPs as a meaningful tool for research applications or for clinical monitoring and diagnosis. (C) 2018 Elsevier Ltd. All rights reserved

Clinical review of retinotopy

Two observations made 29 years apart are the cornerstones of this review on the contributions of Dr Gordon T. Plant to understanding pathology affecting the optic nerve. The first observation laid the anatomical basis in 1990 for the interpretation of optical coherence tomography (OCT) findings in 2009. Retinal OCT offers clinicians detailed in vivo structural imaging of individual retinal layers. This has led to novel observations which were impossible to make using ophthalmoscopy. The technique also helps to re-introduce the anatomically grounded concept of retinotopy to clinical practise. This review employs illustrations of the anatomical basis for retinotopy through detailed translational histological studies and multimodal brain-eye imaging studies. The paths of the prelaminar and postlaminar axons forming the optic nerve and their postsynaptic path from the dorsal lateral geniculate nucleus to the primary visual cortex in humans are described. With the mapped neuroanatomy in mind we use OCT-MRI pairings to discuss the patterns of neurodegeneration in eye and brain that are a consequence of the hard wired retinotopy: anterograde and retrograde axonal degeneration which can, within the visual system, propagate trans-synaptically. The technical advances of OCT and MRI for the first time enable us to trace axonal degeneration through the entire visual system at spectacular resolution. In conclusion, the neuroanatomical insights provided by the combination of OCT and MRI allows us to separate incidental findings from sinister pathology and provides new opportunities to tailor and monitor novel neuroprotective strategies

Electrophysiology of glioma: a Rho GTPase-activating protein reduces tumor growth and spares neuron structure and function

Background. Glioblastomas are the most aggressive type of brain tumor. A successful treatment should aim at halting tumor growth and protecting neuronal cells to prevent functional deficits and cognitive deterioration. Here, we exploited a Rho GTPase-activating bacterial protein toxin, cytotoxic necrotizing factor 1 (CNF1), to interfere with glioma cell growth in vitro and vivo. We also investigated whether this toxin spares neuron structure and function in peritumoral areas. Methods. We performed a microarray transcriptomic and in-depth proteomic analysis to characterize the molecular changes triggered by CNF1 in glioma cells. We also examined tumor cell senescence and growth in vehicle-and CNF1-treated glioma-bearing mice. Electrophysiological and morphological techniques were used to investigate neuronal alterations in peritumoral cortical areas. Results. Administration of CNF1 triggered molecular and morphological hallmarks of senescence in mouse and human glioma cells in vitro. CNF1 treatment in vivo induced glioma cell senescence and potently reduced tumor volumes. In peritumoral areas of glioma-bearing mice, neurons showed a shrunken dendritic arbor and severe functional alterations such as increased spontaneous activity and reduced visual responsiveness. CNF1 treatment enhanced dendritic length and improved several physiological properties of pyramidal neurons, demonstrating functional preservation of the cortical network. Conclusions. Our findings demonstrate that CNF1 reduces glioma volume while at the same time maintaining the physiological and structural properties of peritumoral neurons. These data indicate a promising strategy for the development of more effective antiglioma therapies

Covert deformed wing virus infections have long-term deleterious effects on honeybee foraging and survival

Several studies have suggested that covert stressors can contribute to bee colony declines. Here we provide a novel case study and show using radio-frequency identification (RFID) tracking technology that covert deformed wing virus (DWV) infections in adult honeybee workers seriously impact longterm foraging and survival under natural foraging conditions. In particular, our experiments show that adult workers injected with low doses of DWV experienced increased mortality rates, that DWV caused workers to start foraging at a premature age, and that the virus reduced the workers’ total activity span as foragers. Altogether, these results demonstrate that covert deformed wing virus infections have strongly deleterious effects on honey bee foraging and survival. These results are consistent with previous studies that suggested DWV to be an important contributor to the ongoing bee declines in Europe and the US. Overall, our study underlines the strong impact that covert pathogen infections can have on individual and group-level performance in bees

Propagation of thermal excitations in a cluster of vortices in superfluid 3He-B

We describe the first measurement on Andreev scattering of thermal excitations from a vortex configuration with known density, spatial extent, and orientations in 3He-B superfluid. The heat flow from a blackbody radiator in equilibrium rotation at constant angular velocity is measured with two quartz tuning fork oscillators. One oscillator creates a controllable density of excitations at 0.2Tc base temperature and the other records the thermal response. The results are compared to numerical calculations of ballistic propagation of thermal quasiparticles through a cluster of rectilinear vortices.Comment: 6 pages, 4 figure

Validity of an enhanced EQ-5D-5L measure with an added cognitive dimension in patients with stroke

Objective: The 5-level EuroQoL (EQ-5D-5L) is a patient-reported outcome measure frequently used in stroke research. However, it does not assess the cognitive problems many patients with stroke experience. The aim of this article is to compare the content validity, internal consistency and discriminative ability of the EQ-5D-5L with and without an additional cognitive domain (EQ-5D-5L+C), administered three months post-stroke. Design: Cross-sectional study. Setting: Six general hospitals in the Netherlands. Subjects: In all, 360 individuals with stroke three months after the event. Interventions: Not applicable. Main measures: The modified Rankin Scale and EQ-5D-5L+C were administered in telephone interviews three months post-stroke. Results: A total of 360 patients with stroke were included. Mean age was 68.8 years (standard deviation (SD) = 11.7), 143 (40%) were female, 334 (93%) had had an ischemic stroke, 165 (46%) had a National Institutes of Health Stroke Scale (NIHSS) score ⩽ 4 at presentation and the Barthel Index was 17.2 (SD = 4) four days post-stroke. Cognitive problems were reported by 199 (55%) patients three months post-stroke. Internal consistencies of the EQ-5D-5L and EQ-5D-5L+C were 0.75 and 0.77, respectively. Adding a cognitive domain resulted in a decrease of the ceiling effect from 22% to 14%. Both EQ-5D-5L and EQ-5D-5L+C showed good discriminative ability, but differences between patients with different modified Rankin Scale scores and with/without reported decrease in health and daily activities were slightly larger with the EQ-5D-5L+C compared to the EQ-5D-5L. Conclusions: The EQ-5D-5L+C, which includes a cognitive domain that is highly significant for stroke patients, showed increased content validity and good discriminative ability, without losing internal consistency

Quantum bath suppression in a superconducting circuit by immersion cooling

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Yet, multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at $T\approx 50$ mK -- far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins -- factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid $^3$He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The $^3$He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors