Human Sensory LTP Predicts Memory Performance and Is Modulated by the BDNF Val66Met Polymorphism

Background: Long-term potentiation (LTP) is recognised as a core neuronal process underlying long-term memory. However, a direct relationship between LTP and human memory performance is yet to be demonstrated. The first aim of the current study was thus to assess the relationship between LTP and human long-term memory performance. With this also comes an opportunity to explore factors thought to mediate the relationship between LTP and long-term memory. The second aim of the current study was to explore the relationship between LTP and memory in groups differing with respect to brain-derived neurotrophic factor (BDNF) Val66Met; a single-nucleotide polymorphism (SNP) implicated in memory function.Methods: Participants were split into three genotype groups (Val/Val, Val/Met, Met/Met) and were presented with both an EEG paradigm for inducing LTP-like enhancements of the visually-evoked response, and a test of visual memory.Results: The magnitude of LTP 40 min after induction was predictive of long-term memory performance. Additionally, the BDNF Met allele was associated with both reduced LTP and reduced memory performance.Conclusions: The current study not only presents the first evidence for a relationship between sensory LTP and human memory performance, but also demonstrates how targeting this relationship can provide insight into factors implicated in variation in human memory performance. It is anticipated that this will be of utility to future clinical studies of disrupted memory function

Reading the signs : impact of signed versus written questionnaires on the prevalence of psychopathology among deaf adolescents

Objective: There are no empirically validated measures of psychopathology that can be easily understood by signing deaf children and little reliable data on the prevalence of psychiatric disturbance in this population. The aim was to meet this need by developing an Australian Sign Language (Auslan) version of a widely used measure (the Youth Self-Report; YSR) which could be administered in an interactive CD-ROM format, to assess its reliability, and to compare the prevalence of clinically significant psychopathology in deaf adolescents when using the Auslan questionnaire versus the standard written version. This would also allow examining the validity of written questionnaires in this population. Method: Twenty-nine male and 25 female adolescents with severe or profound hearing loss from public and private schools in the Australian States of Tasmania (n = 11) and New South Wales (n = 43) agreed to participate and completed the written and the interactive Auslan versions of the YSR. Parallel forms were completed by parents (Child Behaviour Checklist) and teachers (Teacher's Report Form). Results: The Auslan version showed comparable reliability to that reported for the standard YSR: internal consistency ( ) ranging from 0.77 to 0.97 and test-retest agreement (r) from 0.49 to 0.78. The interactive Auslan version yielded a prevalence of clinically significant emotional and behavioural problems in deaf adolescents of 42.6% compared with 21.4% when using the standard English version. Prevalence for the wider Australian adolescent population (18.9%) was similar to that obtained among deaf adolescents when using the standard YSR (21.4%). However, it was higher among deaf adolescents (42.6%) when using the Auslan version (OR = 3.2, 95% CI = 1.83-5.58). According to the Auslan version, the syndromes Withdrawn/Depressed (OR = 6.5, 95% CI = 2.96-14.25), Somatic Complaints (OR = 4.8, 95% CI = 2.53-9.22), Social Problems (OR = 8.3, 95% CI = 4.16-16.47) and Thought Problems (OR = 5.7, 95% CI = 2.50-12.80) were much more prevalent among deaf adolescents than in the wider adolescent population, while Attention Problems (OR = 1.1, 95% CI = 0.39-3.17) and Rule-Breaking Behaviour (OR = 1.5, 95% CI = 0.73-3.17) were not. Conclusions: An interactive Auslan version of the YSR is reliable, better accepted and yields higher rates of disturbance than the standard written questionnaire. Clinicians should be aware that using written instruments to assess psychopathology in deaf adolescents may produce invalid results or may underestimate the level of disturbance, particularly emotional problems.9 page(s

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

International audienceSpinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

First low-frequency Einstein@Home all-sky search for continuous gravitational waves in Advanced LIGO data

International audienceWe report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7  [1/Hz]. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of 1.8×10-25. At the low end of our frequency range, 20 Hz, we achieve upper limits of 3.9×10-24. At 55 Hz we can exclude sources with ellipticities greater than 10-5 within 100 pc of Earth with fiducial value of the principal moment of inertia of 1038  kg m2

Search for intermediate mass black hole binaries in the first observing run of Advanced LIGO

International audienceDuring their first observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the first direct detections of gravitational-wave signals produced by stellar-mass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the first employs a matched-filter algorithm that uses a bank of filters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain the rate of several classes of IMBHB mergers. The most stringent limit is obtained for black holes of individual mass 100  M⊙, with spins aligned with the binary orbital angular momentum. For such systems, the merger rate is constrained to be less than 0.93  Gpc−3 yr−1 in comoving units at the 90% confidence level, an improvement of nearly 2 orders of magnitude over previous upper limits

Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo

Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software