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  • Analysis and correction of field fluctuations in fMRI data using field monitoring.

    22 November 2017

    This work investigates the role of magnetic field fluctuations as a confound in fMRI. In standard fMRI experiments with single-shot EPI acquisition at 3 Tesla the uniform and gradient components of the magnetic field were recorded with NMR field sensors. By principal component analysis it is found that differences of field evolution between the EPI readouts are explainable by few components relating to slow and within-shot field dynamics of hardware and physiological origin. The impact of fluctuating field components is studied by selective data correction and assessment of its influence on image fluctuation and SFNR. Physiological field fluctuations, attributed to breathing, were found to be small relative to those of hardware origin. The dominant confounds were hardware-related and attributable to magnet drift and thermal changes. In raw image time series, field fluctuation caused significant SFNR loss, reflected by a 67% gain upon correction. Large part of this correction can be accomplished by traditional image realignment, which addresses slow and spatially uniform field changes. With realignment, explicit field correction increased the SFNR on the order of 6%. In conclusion, field fluctuations are a relevant confound in fMRI and can be addressed effectively by retrospective data correction. Based on the physics involved it is anticipated that the advantage of full field correction increases with field strength, with non-Cartesian readouts, and upon phase-sensitive BOLD analysis.

  • What are we injecting with our drugs?

    23 November 2017

    In preparation for a case, an anaesthetist opened a 20 ml glass vial of propofol and aspirated the propofol into a syringe via a blunt drawing-up needle. Increased resistance was felt with aspiration. On inspection, a shard of glass was found at the tip of the drawing-up needle. The shard was presumed to be from the propofol ampoule, and to have fallen into the solution upon snapping open its glass tip. This illustrative case raises the issue of contamination of drugs by particles introduced during the drawing-up process. It also highlights the possibility that during the drawing-up process, intravenous drugs may become contaminated not just with particles, but with microorganisms on the surface of the particles. In this article, we discuss relevant recent research of the implications of this type of drug contamination. We draw attention to the need for meticulous care in drawing up and administering intravenous drugs during anaesthesia, particularly propofol.

  • Targeting retinal ganglion cell recovery.

    23 November 2017

    Accumulating evidence from experimental and clinical studies suggest that retinal ganglion cells at least in the earlier stages of glaucoma have the capacity to recover function following periods of functional loss. The capacity for recovery may be negatively impacted by advancing age but can be boosted by interventions such as diet restriction and exercise.

  • A retrospective survey of substance abuse in anaesthetists in Australia and New Zealand from 2004 to 2013.

    23 November 2017

    A questionnaire on substance abuse was distributed electronically to the heads of 185 Australian and New Zealand College of Anaesthetists accredited anaesthesia departments in Australia and New Zealand. The response rate was 57%. From January 2004 to December 2013, 61 cases of substance abuse were identified, giving an estimated incidence of 1.2 cases per 1000 anaesthetist years. Of 44 detailed reports completed, the majority were aged between 30 and 49 years, were male and of specialist grade. However, when corrected for gender and grade, the estimated overall incidence was higher in females and twice as high for trainees compared with specialists. When compared with prior surveys, the pattern of substance abuse in Australia and New Zealand appears to have changed significantly, with a notable increase in propofol and alcohol abuse and a decrease in reported cases of opioid abuse. Common presenting features of abuse included intoxication and witnessed abuse. Seventy percent of cases had more than one comorbid condition, most frequently either mental health or family problems. Only 32% of abusers had made a long-term recovery within the specialty. Death was the eventual outcome in 18% overall, with a particularly high mortality associated with propofol abuse (45%). Trainee suicide from all causes was reported at three times the rate of specialists. The findings indicate that substance abuse remains a significant problem in Australia and New Zealand and is associated with a significant mortality rate.

  • Constitutive spectral EEG peaks in the gamma range: suppressed by sleep, reduced by mental activity and resistant to sensory stimulation.

    23 November 2017

    OBJECTIVE: In a systematic study of gamma activity in neuro-psychiatric disease, we unexpectedly observed distinctive, apparently persistent, electroencephalogram (EEG) spectral peaks in the gamma range (25-100 Hz). Our objective, therefore, was to examine the incidence, distribution and some of the characteristics of these peaks. METHODS: High sample-rate, 128-channel, EEG was recorded in 603 volunteers (510 with neuropsychiatric disorders, 93 controls), whilst performing cognitive tasks, and converted to power spectra. Peaks of spectral power, including in the gamma range, were determined algorithmically for all electrodes. To determine if peaks were stable, 24-h ambulatory recordings were obtained from 16 subjects with peaks. In 10 subjects, steady-state responses to stimuli at peak frequency were compared with off-peak-frequency stimulation to determine if peaks were a feature of underlying network resonances and peaks were evaluated with easy and hard versions of oddball tasks to determine if peaks might be influenced by mental effort. RESULTS: 57% of 603 subjects exhibited peaks >2 dB above trough power at or above 25 Hz. Larger peaks (>5 dB) were present in 13% of subjects. Peaks were distributed widely over the scalp, more frequent centrally. Peaks were present through the day and were suppressed by slow-wave-sleep. Steady-state responses were the same with on- or off-peak sensory stimulation. In contrast, mental effort resulted in reductions in power and frequency of gamma peaks, although the suppression did not correlate with level of effort. CONCLUSIONS: Gamma EEG can be expressed constitutively as concentrations of power in narrow or wide frequency bands that play an, as yet, unknown role in cognitive activity. SIGNIFICANCE: These findings expand the described range of rhythmic EEG phenomena. In particular, in addition to evoked, induced and sustained gamma band activity, gamma activity can be present constitutively in spectral peaks.

  • SILENCE

    13 April 2016

  • SILENCE

    13 April 2016

    The SILENCE programme is a series of linked research projects. Updates on progress will be posted here.

  • SILENCE

    13 April 2016

  • SILENCE

    21 April 2017

    Contact details for the SILENCE research programme

  • Non-contact vital signs monitoring

    20 September 2016

    The non-contact vital signs monitoring (NVSM) study is a joint collaboration between the Department of Engineering, the Nuffield Department of Clinical Neurosciences, and Oxehealth Ltd.

  • NVSM

    25 October 2016

    Significant project milestones will be displayed here

  • NVSM

    20 September 2016

    Contact details for the non-contact vital signs monitoring research team

  • NIHR LCRN Studies

    30 June 2016

    The Critical Care Research Group undertakes a number of studies that are adopted by the NIHR local research network portfolio.

  • HAVEN

    10 May 2016

    The HAVEN project is funded by the Health Innovation Challenge Fund, a joint venture supported by the Wellcome Trust and the Department of Health.

  • HAVEN

    10 May 2016

    The HAVEN project is funded by the Health Innovation Challenge Fund, a joint venture supported by the Wellcome Trust and the Department of Health.

  • Circadian and Visual Neuroscience (Foster)

    15 January 2013

    NLO

    Our research interests range across the neurosciences but with specific interests in circadian, visual and behavioural neuroscience.

  • Circadian and Visual Neuroscience (Peirson)

    15 January 2013

    NLO

    Our research focuses on the non-image forming function of the eye, including how the light environment regulates sleep and circadian rhythms and how these responses are affected in disease.

  • Retinal Cell Biology and Degeneration

    15 January 2013

    NLO

    The discovery of a novel inner retinal photoreceptor cell, driving non-visual functions, has had a significant impact on the retinal neuroscience field. My research focuses on understanding the physiology and function of these photosensitive retinal ganglion cells.

  • Oxford Smart Specs Research Group

    13 June 2014

    DCN NLO

    We are developing a set of 'smart' electronic glasses (‘smart specs’) to enhance sight for the visually impaired.

  • Vision Group

    13 February 2014

    FMRIB NLO

    We use brain imaging techniques to investigate the human visual system, both in its normal state and in disease and disorder.

  • FMRIB P.A.I.N Group

    19 January 2015

    FMRIB NDA

    The Pain Analgesia/Anaesthesia Imaging Neuroscience group is a multidisciplinary team of scientists and clinicians. We research how the human central nervous system generates and modulates painful experiences in acute and chronic settings.

  • NeuroMetrology Lab

    13 April 2016

    DCN NDCN

    Our objective is to develop ways of accurately measuring neurological disorders such as Parkinson's disease.

  • Glioma Neurosurgery Research Group

    11 February 2016

    FMRIB NDCN

    Our research aims to understand the characteristics of individual brain tumours, combining cutting edge brain imaging, molecular neuropathology and neurosurgical techniques to develop personalized approaches for first-line cancer surgery.

  • Parkinson’s Neuropathology Group

    23 February 2016

    DCN

    We study why certain neuronal populations are vulnerable to neurodegeneration in Parkinson’s disease brain and whether pathological changes seen in the peripheral tissues mirror or precede what is ultimately seen in the brain, and how this can be used to develop biomarkers.