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  1. Article ; Online: Ultrasound-guided, open-source microneurography: Approaches to improve recordings from peripheral nerves in man.

    Dunham, James P / Sales, Anna C / Pickering, Anthony E

    Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology

    2018  Volume 129, Issue 11, Page(s) 2475–2481

    Abstract: Objective: Microneurography is the only method for recording from single neurons in intact human nerves. It is challenging - requiring technical expertise, investment in specialised equipment and has sparse data yields.: Methods: We assessed whether ... ...

    Abstract Objective: Microneurography is the only method for recording from single neurons in intact human nerves. It is challenging - requiring technical expertise, investment in specialised equipment and has sparse data yields.
    Methods: We assessed whether ultrasound guidance in combination with an 'open access' amplifier and data capture system (Open-Ephys) would simplify and expand the scope of microneurographic recordings in humans.
    Results: In 32 healthy consenting volunteers, ultrasound-guidance improved success rates for obtaining cutaneous C-fibres and reduced "Skin to Nerve" times from 28.5 min to 4.5 min for recordings of the peroneal nerve (P < 0.0001). We illustrate the potential utility of ultrasound-guided microneurography for difficult to access nerves with phrenic nerve recording during a Valsalva manoeuvre. We show that Open Ephys is a viable alternative to commercially available recording systems and offers advantages in terms of cost and software customisability.
    Conclusions: Ultrasound guidance for microneurography with Open Ephys facilitates cutaneous C nociceptor recordings and allows recordings to be made from nerves previously considered inaccessible.
    Significance: We anticipate that the adoption of these techniques will improve microneurography experimental efficiency, adds an important visual learning aid and increases the generalisability of the approach.
    MeSH term(s) Adult ; Electrophysiology/methods ; Electrophysiology/standards ; Humans ; Male ; Middle Aged ; Nerve Fibers, Unmyelinated/physiology ; Neural Conduction ; Phrenic Nerve/cytology ; Phrenic Nerve/physiology ; Ultrasonography/methods
    Language English
    Publishing date 2018-07-29
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1463630-x
    ISSN 1872-8952 ; 0921-884X ; 1388-2457
    ISSN (online) 1872-8952
    ISSN 0921-884X ; 1388-2457
    DOI 10.1016/j.clinph.2018.07.011
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Open-Source Real-Time Closed-Loop Electrical Threshold Tracking for Translational Pain Research.

    Nickerson, Aidan P / Newton, Graeme W T / O'Sullivan, James H / Martinez-Perez, Manuel / Sales, Anna C / Williams, Gethin / Pickering, Anthony E / Dunham, James P

    Journal of visualized experiments : JoVE

    2023  , Issue 194

    Abstract: Nociceptors are a class of primary afferent neurons that signal potentially harmful noxious stimuli. An increase in nociceptor excitability occurs in acute and chronic pain conditions. This produces abnormal ongoing activity or reduced activation ... ...

    Abstract Nociceptors are a class of primary afferent neurons that signal potentially harmful noxious stimuli. An increase in nociceptor excitability occurs in acute and chronic pain conditions. This produces abnormal ongoing activity or reduced activation thresholds to noxious stimuli. Identifying the cause of this increased excitability is required for the development and validation of mechanism-based treatments. Single-neuron electrical threshold tracking can quantify nociceptor excitability. Therefore, we have developed an application to allow such measurements and demonstrate its use in humans and rodents. APTrack provides real-time data visualization and action potential identification using a temporal raster plot. Algorithms detect action potentials by threshold crossing and monitor their latency after electrical stimulation. The plugin then modulates the electrical stimulation amplitude using an up-down method to estimate the electrical threshold of the nociceptors. The software was built upon the Open Ephys system (V0.54) and coded in C++ using the JUCE framework. It runs on Windows, Linux, and Mac operating systems. The open-source code is available (https://github.com/Microneurography/APTrack). The electrophysiological recordings were taken from nociceptors in both a mouse skin-nerve preparation using the teased fiber method in the saphenous nerve and in healthy human volunteers using microneurography in the superficial peroneal nerve. Nociceptors were classified by their response to thermal and mechanical stimuli, as well as by monitoring the activity-dependent slowing of the conduction velocity. The software facilitated the experiment by simplifying the action potential identification through the temporal raster plot. We demonstrate real-time closed-loop electrical threshold tracking of single-neuron action potentials during in vivo human microneurography, for the first time, and during ex vivo mouse electrophysiological recordings of C-fibers and Aδ-fibers. We establish proof of principle by showing that the electrical threshold of a human heat-sensitive C-fiber nociceptor is reduced by heating the receptive field. This plugin enables the electrical threshold tracking of single-neuron action potentials and allows the quantification of changes in nociceptor excitability.
    MeSH term(s) Humans ; Mice ; Animals ; Nerve Fibers, Unmyelinated/physiology ; Action Potentials/physiology ; Nociceptors/physiology ; Electric Stimulation ; Pain ; Skin/innervation ; Pain Threshold/physiology
    Language English
    Publishing date 2023-04-21
    Publishing country United States
    Document type Journal Article ; Video-Audio Media ; Research Support, Non-U.S. Gov't
    ZDB-ID 2259946-0
    ISSN 1940-087X ; 1940-087X
    ISSN (online) 1940-087X
    ISSN 1940-087X
    DOI 10.3791/64898
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Locus Coeruleus tracking of prediction errors optimises cognitive flexibility: An Active Inference model.

    Sales, Anna C / Friston, Karl J / Jones, Matthew W / Pickering, Anthony E / Moran, Rosalyn J

    PLoS computational biology

    2019  Volume 15, Issue 1, Page(s) e1006267

    Abstract: The locus coeruleus (LC) in the pons is the major source of noradrenaline (NA) in the brain. Two modes of LC firing have been associated with distinct cognitive states: changes in tonic rates of firing are correlated with global levels of arousal and ... ...

    Abstract The locus coeruleus (LC) in the pons is the major source of noradrenaline (NA) in the brain. Two modes of LC firing have been associated with distinct cognitive states: changes in tonic rates of firing are correlated with global levels of arousal and behavioural flexibility, whilst phasic LC responses are evoked by salient stimuli. Here, we unify these two modes of firing by modelling the response of the LC as a correlate of a prediction error when inferring states for action planning under Active Inference (AI). We simulate a classic Go/No-go reward learning task and a three-arm 'explore/exploit' task and show that, if LC activity is considered to reflect the magnitude of high level 'state-action' prediction errors, then both tonic and phasic modes of firing are emergent features of belief updating. We also demonstrate that when contingencies change, AI agents can update their internal models more quickly by feeding back this state-action prediction error-reflected in LC firing and noradrenaline release-to optimise learning rate, enabling large adjustments over short timescales. We propose that such prediction errors are mediated by cortico-LC connections, whilst ascending input from LC to cortex modulates belief updating in anterior cingulate cortex (ACC). In short, we characterise the LC/ NA system within a general theory of brain function. In doing so, we show that contrasting, behaviour-dependent firing patterns are an emergent property of the LC that translates state-action prediction errors into an optimal balance between plasticity and stability.
    MeSH term(s) Animals ; Cognition/physiology ; Computational Biology ; Learning/physiology ; Locus Coeruleus/physiology ; Models, Neurological ; Norepinephrine/metabolism ; Reward
    Chemical Substances Norepinephrine (X4W3ENH1CV)
    Language English
    Publishing date 2019-01-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2193340-6
    ISSN 1553-7358 ; 1553-734X
    ISSN (online) 1553-7358
    ISSN 1553-734X
    DOI 10.1371/journal.pcbi.1006267
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Probabilistic, spinally-gated control of bladder pressure and autonomous micturition by Barrington's nucleus CRH neurons.

    Ito, Hiroki / Sales, Anna C / Fry, Christopher H / Kanai, Anthony J / Drake, Marcus J / Pickering, Anthony E

    eLife

    2020  Volume 9

    Abstract: Micturition requires precise control of bladder and urethral sphincter via parasympathetic, sympathetic and somatic motoneurons. This involves a spino-bulbospinal control circuit incorporating Barrington's nucleus in the pons (Barr). Ponto-spinal ... ...

    Abstract Micturition requires precise control of bladder and urethral sphincter via parasympathetic, sympathetic and somatic motoneurons. This involves a spino-bulbospinal control circuit incorporating Barrington's nucleus in the pons (Barr). Ponto-spinal glutamatergic neurons that express corticotrophin-releasing hormone (CRH) form one of the largest Barr cell populations. Barr
    MeSH term(s) Animals ; Barrington's Nucleus/physiopathology ; Corticotropin-Releasing Hormone/metabolism ; Mice ; Neural Pathways/physiology ; Neurons/physiology ; Pons/cytology ; Pons/physiology ; Spinal Cord/physiology ; Urinary Bladder/physiopathology ; Urination/physiology
    Chemical Substances Corticotropin-Releasing Hormone (9015-71-8)
    Language English
    Publishing date 2020-04-29
    Publishing country England
    Document type Journal Article
    ZDB-ID 2687154-3
    ISSN 2050-084X ; 2050-084X
    ISSN (online) 2050-084X
    ISSN 2050-084X
    DOI 10.7554/eLife.56605
    Database MEDical Literature Analysis and Retrieval System OnLINE

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