225 research outputs found
Retinal metric: a stimulus distance measure derived from population neural responses
Full text linkThe ability of the organism to distinguish between various stimuli is limited
by the structure and noise in the population code of its sensory neurons. Here
we infer a distance measure on the stimulus space directly from the recorded
activity of 100 neurons in the salamander retina. In contrast to previously
used measures of stimulus similarity, this "neural metric" tells us how
distinguishable a pair of stimulus clips is to the retina, given the noise in
the neural population response. We show that the retinal distance strongly
deviates from Euclidean, or any static metric, yet has a simple structure: we
identify the stimulus features that the neural population is jointly sensitive
to, and show the SVM-like kernel function relating the stimulus and neural
response spaces. We show that the non-Euclidean nature of the retinal distance
has important consequences for neural decoding.Comment: 5 pages, 4 figures, to appear in Phys Rev Let
Maternal sleep practices and stillbirth: Findings from an international case‐control study
No full textBackground:
Late stillbirth, which occurs ≥28 weeks’ gestation, affects 1.3‐8.8 per 1000 births in high‐income countries. Of concern, most occur in women without established risk factors. Identification of potentially modifiable risk factors that relate to maternal behaviors remains a priority in stillbirth prevention research. This study aimed to investigate, in an international cohort, whether maternal sleep practices are related to late stillbirth.
Methods:
An Internet‐based case‐control study of women who had a stillbirth ≥28 weeks’ gestation within 30 days before completing the survey (n = 153) and women with an ongoing third‐trimester pregnancy or who had delivered a live born child within 30 days (n = 480). Bivariate and multivariate logistic regressions were used to determine unadjusted and adjusted odds ratios (OR and aOR, respectively) with 95% confidence intervals (95% CIs) for stillbirth.
Results:
Sleeping >9 hours per night in the previous month was associated with stillbirth (aOR 1.75 [95% CI 1.10‐2.79]), as was waking on the right side (2.27 [1.31‐3.92]). Nonrestless sleep in the last month was also found to be associated with stillbirth (1.73 [1.03‐2.99]), with good sleep quality in the last month approaching significance (1.64 [0.98‐2.75]). On the last night of pregnancy, not waking more than one time was associated with stillbirth (2.03 [1.24‐3.34]). No relationship was found with going to sleep position during pregnancy, although very few women reported settling in the supine position (2.4%).
Conclusions:
Long periods of undisturbed sleep are associated with late stillbirth. Physiological studies of how the neuroendocrine and autonomic system pathways are regulated during sleep in the context of late pregnancy are warranted
An international internet survey of the experiences of 1,714 mothers with a late stillbirth: The STARS cohort study
Get PDFBackground: Stillbirth occurring after 28 weeks gestation affects between 1.5-4.5 per 1,000 births in high-income countries. The majority of stillbirths in this setting occur in women without risk factors. In addition, many established risk factors such as nulliparity and maternal age are not amenable to modification during pregnancy. Identification of other risk factors which could be amenable to change in pregnancy should be a priority in stillbirth prevention research. Therefore, this study aimed to utilise an online survey asking women who had a stillbirth about their pregnancy in order to identify any common symptoms and experiences. Methods: A web-based survey. Results: A total of 1,714 women who had experienced a stillbirth >3 weeks prior to enrolment completed the survey. Common experiences identified were: perception of changes in fetal movement (63 % of respondents), reports of a "gut instinct" that something was wrong (68 %), and perceived time of death occurring overnight (56 %). A quarter of participants believed that their baby's death was due to a cord issue and another 18 % indicated that they did not know the reason why their baby died. In many cases (55 %) the mother believed the cause of death was different to that told by clinicians. Conclusions: This study confirms the association between altered fetal movements and stillbirth and highlights novel associations that merit closer scrutiny including a maternal gut instinct that something was wrong. The potential importance of maternal sleep is highlighted by the finding of more than half the mothers believing their baby died during the night. This study supports the importance of listening to mothers' concerns and symptoms during pregnancy and highlights the need for thorough investigation of stillbirth and appropriate explanation being given to parents
Stimulus-dependent maximum entropy models of neural population codes
Get PDFNeural populations encode information about their stimulus in a collective
fashion, by joint activity patterns of spiking and silence. A full account of
this mapping from stimulus to neural activity is given by the conditional
probability distribution over neural codewords given the sensory input. To be
able to infer a model for this distribution from large-scale neural recordings,
we introduce a stimulus-dependent maximum entropy (SDME) model---a minimal
extension of the canonical linear-nonlinear model of a single neuron, to a
pairwise-coupled neural population. The model is able to capture the
single-cell response properties as well as the correlations in neural spiking
due to shared stimulus and due to effective neuron-to-neuron connections. Here
we show that in a population of 100 retinal ganglion cells in the salamander
retina responding to temporal white-noise stimuli, dependencies between cells
play an important encoding role. As a result, the SDME model gives a more
accurate account of single cell responses and in particular outperforms
uncoupled models in reproducing the distributions of codewords emitted in
response to a stimulus. We show how the SDME model, in conjunction with static
maximum entropy models of population vocabulary, can be used to estimate
information-theoretic quantities like surprise and information transmission in
a neural population.Comment: 11 pages, 7 figure
Rehabilitation via HOMe Based gaming exercise for the Upper-limb post Stroke (RHOMBUS): a qualitative analysis of participants’ experience
Get PDFObjective To report participants’ experiences of trial processes and use of the Neurofenix platform for home-based rehabilitation following stroke. The platform, consisting of the NeuroBall device and Neurofenix app, is a non-immersive virtual reality tool to facilitate upper limb rehabilitation following stroke. The platform has recently been evaluated and demonstrated to be safe and effective through a non-randomised feasibility trial (RHOMBUS).
Design Qualitative approach using semistructured interviews. Interviews were audio recorded, transcribed verbatim and analysed using the framework method.
Setting Participants’ homes, South-East England.
Participants Purposeful sample of 18 adults (≥18 years), minimum 12 weeks following stroke, not receiving upper limb rehabilitation prior to the RHOMBUS trial, scoring 9–25 on the Motricity Index (elbow and shoulder), with sufficient cognitive and communicative abilities to participate.
Results Five themes were developed which explored both trial processes and experiences of using the platform. Factors that influenced participant’s decision to take part in the trial, their perceptions of support provided during the trial and communication with the research team were found to be important contextual factors effecting participants’ overall experience. Specific themes around usability and comfort of the NeuroBall device, factors motivating persistence and perceived effectiveness of the intervention were highlighted as being central to the usability and acceptability of the platform.
Conclusion This study demonstrated the overall acceptability of the platform and identified areas for enhancement which have since been implemented by Neurofenix. The findings add to the developing literature on the interface between virtual reality systems and user experience.
Trial registration number ISRCTN60291412.Innovate UK (grant number: 104188
Hepatic leptospiral infections in dogs without obvious renal involvement.
Get PDFBACKGROUND: Reports of chronic hepatitis in dogs caused by Leptospira spp. are confined to small case series. Fluorescence in situ hybridization (FISH) allows the identification of spirochetes in liver samples. Consequently, this technique may help elucidate the role of Leptospira spp. in cases of chronic hepatitis. OBJECTIVES: To describe cases of hepatic leptospirosis in dogs diagnosed by FISH and subsequent polymerase chain reaction (PCR) speciation, with the absence of clinically relevant renal involvement. ANIMALS: Ten client-owned dogs. METHODS: Retrospective case series from the University of Cambridge presented between 2013 and 2016 or cases consulted by telephone advice during this time period. Cases were selected based on histopathologically confirmed granulomatous hepatitis and leptospiral organisms identified by FISH and PCR speciation (Leptospira interrogans/kirschneri). RESULTS: All cases had increased liver enzyme activities, and FISH in combination with PCR speciation-confirmed infection with L. interrogans/kirschneri. Four dogs underwent repeat liver biopsy, FISH and PCR speciation 4-15 months after initial presentation and doxycycline treatment with 1 dog undergoing repeat sampling at necropsy. Three dogs that underwent repeat biopsy remained positive for L. interrogans/kirschneri infection. Six dogs were alive at the time of manuscript preparation and 4 dogs were euthanized as a result of progressive liver disease. CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of hepatic leptospiral organisms may be associated with chronic granulomatous hepatitis without clinical evidence of renal involvement. Further studies are necessary to elucidate the etiological role of these organisms in the disease
Rehabilitation via home based gaming exercise for the upper-limb post stroke (RHOMBUS): results of an intervention feasibility trial
Get PDFInnovate UK grant number 10418
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CRLF3 plays a key role in the final stage of platelet genesis and is a potential therapeutic target for thrombocythemia.
Get PDFThe process of platelet production has so far been understood to be a 2-stage process: megakaryocyte maturation from hematopoietic stem cells followed by proplatelet formation, with each phase regulating the peripheral blood platelet count. Proplatelet formation releases into the bloodstream beads-on-a-string preplatelets, which undergo fission into mature platelets. For the first time, we show that preplatelet maturation is a third, tightly regulated, critical process akin to cytokinesis that regulates platelet count. We show that deficiency in cytokine receptor-like factor 3 (CRLF3) in mice leads to an isolated and sustained 25% to 48% reduction in the platelet count without any effect on other blood cell lineages. We show that Crlf3-/- preplatelets have increased microtubule stability, possibly because of increased microtubule glutamylation via the interaction of CRLF3 with key members of the Hippo pathway. Using a mouse model of JAK2 V617F essential thrombocythemia, we show that a lack of CRLF3 leads to long-term lineage-specific normalization of the platelet count. We thereby postulate that targeting CRLF3 has therapeutic potential for treatment of thrombocythemia
Rehabilitation using virtual gaming for Hospital and hOME Based training for the Upper limb post Stroke (RHOMBUS II): a feasibility randomised controlled trial
Get PDFMeeting abstract presented at the 17th UK Stroke Forum Conference, 29th November – 1st December 2022, Liverpool ACC, UK.Introduction: Stroke survivors can experience persistent upper-limb (UL) weakness. Intense practice and repetition of movement are key to effective UL rehabilitation. Yet, practice falls short of the dosage needed to drive recovery. Technology offers solutions to increase training opportunities. The NeuroBall is a co-designed portable device for all-in-one arm training through a uniquely designed rehabilitation gaming app, displayed on a tablet computer. This study aimed to determine the safety, feasibility and acceptability of the NeuroBall in the subacute inpatient and ESD stroke pathways when practice can be most effective.
Method: Single-site feasibility RCT with non-blinded outcomes at seven weeks. Twenty-four sub-acute stroke with new unilateral weakness were randomised (Intervention n=16; control n=8). Both groups received UL usual care; the intervention group, once trained, used the NeuroBall for seven weeks. Outcomes included arm impairment, arm function, pain, fatigue and self-efficacy for exercising alone, participant satisfaction, device usage and adverse events (AEs) and missing data.
Results: Twenty-four participants were recruited, eighteen completed all stages. Outcome measures were suitable, and there was minimal missing data (less than 10%). Participants undertook an additional 13 hours of UL rehabilitation, completing an average of 15, 133 UL repetitions. The mean satisfaction score (QUEST) was 35/40. Eight AEs were reported, six in the intervention group and two in the control, five were unrelated, one related, one probable and one possibly.
Conclusion: The NeuroBall is safe, enjoyable and easy to use for training the UL in the subacute stroke pathway both as an inpatient and early weeks at home
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