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  1. Article: Impact of DC-Coupled Electrophysiological Recordings for Translational Neuroscience: Case Study of Tracking Neural Dynamics in Rodent Models of Seizures.

    Jafarian, Amirhossein / Wykes, Rob C

    Frontiers in computational neuroscience

    2022  Volume 16, Page(s) 900063

    Abstract: We propose that to fully understand biological mechanisms underlying pathological brain activity with transitions (e.g., into and out of seizures), wide-bandwidth electrophysiological recordings are important. We demonstrate the importance of ultraslow ... ...

    Abstract We propose that to fully understand biological mechanisms underlying pathological brain activity with transitions (e.g., into and out of seizures), wide-bandwidth electrophysiological recordings are important. We demonstrate the importance of ultraslow potential shifts and infraslow oscillations for reliable tracking of synaptic physiology, within a neural mass model, from brain recordings that undergo pathological phase transitions. We use wide-bandwidth data (direct current (DC) to high-frequency activity), recorded using epidural and penetrating graphene micro-transistor arrays in a rodent model of acute seizures. Using this technological approach, we capture the dynamics of infraslow changes that contribute to seizure initiation (active pre-seizure DC shifts) and progression (passive DC shifts). By employing a continuous-discrete unscented Kalman filter, we track biological mechanisms from full-bandwidth data with and without active pre-seizure DC shifts during paroxysmal transitions. We then apply the same methodological approach for tracking the same parameters after application of high-pass-filtering >0.3Hz to both data sets. This approach reveals that ultraslow potential shifts play a fundamental role in the transition to seizure, and the use of high-pass-filtered data results in the loss of key information in regard to seizure onset and termination dynamics.
    Language English
    Publishing date 2022-07-21
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2452964-3
    ISSN 1662-5188
    ISSN 1662-5188
    DOI 10.3389/fncom.2022.900063
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The advantages of mapping slow brain potentials using DC-coupled graphene micro-transistors: Clinical and translational applications.

    Wykes, Rob C / Masvidal-Codina, Eduard / Guimerà-Brunet, Anton / Garrido, Jose A

    Clinical and translational medicine

    2022  Volume 12, Issue 7, Page(s) e968

    MeSH term(s) Brain ; Graphite ; Nanostructures ; Transistors, Electronic
    Chemical Substances Graphite (7782-42-5)
    Language English
    Publishing date 2022-10-04
    Publishing country United States
    Document type Editorial ; Research Support, Non-U.S. Gov't
    ZDB-ID 2697013-2
    ISSN 2001-1326 ; 2001-1326
    ISSN (online) 2001-1326
    ISSN 2001-1326
    DOI 10.1002/ctm2.968
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Concurrent functional ultrasound imaging with graphene-based DC-coupled electrophysiology as a platform to study slow brain signals and cerebral blood flow under control and pathophysiological brain states.

    Zhang, Julie Meng / Masvidal-Codina, Eduard / Nguyen, Diep / Illa, Xavi / Dégardin, Julie / Goulet, Ruben / Prats-Alfonso, Elisabet / Matsoukis, Stratis / Guger, Christoph / Garrido, Jose Antonio / Picaud, Serge / Guimerà-Brunet, Anton / Wykes, Rob C

    Nanoscale horizons

    2024  Volume 9, Issue 4, Page(s) 544–554

    Abstract: Current methodology used to investigate how shifts in brain states associated with regional cerebral blood volume (CBV) change in deep brain areas, are limited by either the spatiotemporal resolution of the CBV techniques, and/or compatibility with ... ...

    Abstract Current methodology used to investigate how shifts in brain states associated with regional cerebral blood volume (CBV) change in deep brain areas, are limited by either the spatiotemporal resolution of the CBV techniques, and/or compatibility with electrophysiological recordings; particularly in relation to spontaneous brain activity and the study of individual events. Additionally, infraslow brain signals (<0.1 Hz), including spreading depolarisations, DC-shifts and infraslow oscillations (ISO), are poorly captured by traditional AC-coupled electrographic recordings; yet these very slow brain signals can profoundly change CBV. To gain an improved understanding of how infraslow brain signals couple to CBV we present a new method for concurrent CBV with wide bandwidth electrophysiological mapping using simultaneous functional ultrasound imaging (fUS) and graphene-based field effect transistor (gFET) DC-coupled electrophysiological acquisitions. To validate the feasibility of this methodology visually-evoked neurovascular coupling (NVC) responses were examined. gFET recordings are not affected by concurrent fUS imaging, and epidural placement of gFET arrays within the imaging window did not deteriorate fUS signal quality. To examine directly the impact of infra-slow potential shifts on CBV, cortical spreading depolarisations (CSDs) were induced. A biphasic pattern of decreased, followed by increased CBV, propagating throughout the ipsilateral cortex, and a delayed decrease in deeper subcortical brain regions was observed. In a model of acute seizures, CBV oscillations were observed prior to seizure initiation. Individual seizures occurred on the rising phase of both infraslow brain signal and CBV oscillations. When seizures co-occurred with CSDs, CBV responses were larger in amplitude, with delayed CBV decreases in subcortical structures. Overall, our data demonstrate that gFETs are highly compatible with fUS and allow concurrent examination of wide bandwidth electrophysiology and CBV. This graphene-enabled technological advance has the potential to improve our understanding of how infraslow brain signals relate to CBV changes in control and pathological brain states.
    MeSH term(s) Humans ; Graphite ; Brain/diagnostic imaging ; Seizures ; Electrophysiology ; Cerebrovascular Circulation/physiology ; Ultrasonography
    Chemical Substances Graphite (7782-42-5)
    Language English
    Publishing date 2024-03-25
    Publishing country England
    Document type Journal Article
    ISSN 2055-6764
    ISSN (online) 2055-6764
    DOI 10.1039/d3nh00521f
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  4. Article ; Online: Adiabatic dynamic causal modelling.

    Jafarian, Amirhossein / Zeidman, Peter / Wykes, Rob C / Walker, Matthew / Friston, Karl J

    NeuroImage

    2021  Volume 238, Page(s) 118243

    Abstract: This technical note introduces adiabatic dynamic causal modelling, a method for inferring slow changes in biophysical parameters that control fluctuations of fast neuronal states. The application domain we have in mind is inferring slow changes in ... ...

    Abstract This technical note introduces adiabatic dynamic causal modelling, a method for inferring slow changes in biophysical parameters that control fluctuations of fast neuronal states. The application domain we have in mind is inferring slow changes in variables (e.g., extracellular ion concentrations or synaptic efficacy) that underlie phase transitions in brain activity (e.g., paroxysmal seizure activity). The scheme is efficient and yet retains a biophysical interpretation, in virtue of being based on established neural mass models that are equipped with a slow dynamic on the parameters (such as synaptic rate constants or effective connectivity). In brief, we use an adiabatic approximation to summarise fast fluctuations in hidden neuronal states (and their expression in sensors) in terms of their second order statistics; namely, their complex cross spectra. This allows one to specify and compare models of slowly changing parameters (using Bayesian model reduction) that generate a sequence of empirical cross spectra of electrophysiological recordings. Crucially, we use the slow fluctuations in the spectral power of neuronal activity as empirical priors on changes in synaptic parameters. This introduces a circular causality, in which synaptic parameters underwrite fast neuronal activity that, in turn, induces activity-dependent plasticity in synaptic parameters. In this foundational paper, we describe the underlying model, establish its face validity using simulations and provide an illustrative application to a chemoconvulsant animal model of seizure activity.
    MeSH term(s) Action Potentials/physiology ; Brain/physiology ; Connectome ; Electroencephalography ; Humans ; Models, Neurological ; Nerve Net/physiology ; Neurons/physiology
    Language English
    Publishing date 2021-06-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2021.118243
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  5. Article ; Online: Indirect Effects of Halorhodopsin Activation: Potassium Redistribution, Nonspecific Inhibition, and Spreading Depolarization.

    Parrish, R Ryley / MacKenzie-Gray Scott, Connie / Jackson-Taylor, Tom / Grundmann, Alex / McLeod, Faye / Codadu, Neela K / Călin, Alexandru / Alfonsa, Hannah / Wykes, Rob C / Voipio, Juha / Trevelyan, Andrew J

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2022  Volume 43, Issue 5, Page(s) 685–692

    Abstract: The movement of ions in and out of neurons can exert significant effects on neighboring cells. Here we report several experimentally important consequences of activation of the optogenetic chloride pump, halorhodopsin. We recorded extracellular ... ...

    Abstract The movement of ions in and out of neurons can exert significant effects on neighboring cells. Here we report several experimentally important consequences of activation of the optogenetic chloride pump, halorhodopsin. We recorded extracellular K
    MeSH term(s) Male ; Female ; Mice ; Animals ; Potassium/metabolism ; Halorhodopsins/pharmacology ; Chlorides/metabolism ; Neurons/metabolism ; Pyramidal Cells/metabolism ; Cortical Spreading Depression/physiology
    Chemical Substances Potassium (RWP5GA015D) ; Halorhodopsins ; Chlorides
    Language English
    Publishing date 2022-12-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.1141-22.2022
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  6. Article ; Online: Genetic dissection of down syndrome-associated alterations in APP/amyloid-β biology using mouse models.

    Tosh, Justin L / Rhymes, Elena R / Mumford, Paige / Whittaker, Heather T / Pulford, Laura J / Noy, Sue J / Cleverley, Karen / Walker, Matthew C / Tybulewicz, Victor L J / Wykes, Rob C / Fisher, Elizabeth M C / Wiseman, Frances K

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 5736

    Abstract: Individuals who have Down syndrome (caused by trisomy of chromosome 21), have a greatly elevated risk of early-onset Alzheimer's disease, in which amyloid-β accumulates in the brain. Amyloid-β is a product of the chromosome 21 gene APP (amyloid precursor ...

    Abstract Individuals who have Down syndrome (caused by trisomy of chromosome 21), have a greatly elevated risk of early-onset Alzheimer's disease, in which amyloid-β accumulates in the brain. Amyloid-β is a product of the chromosome 21 gene APP (amyloid precursor protein) and the extra copy or 'dose' of APP is thought to be the cause of this early-onset Alzheimer's disease. However, other chromosome 21 genes likely modulate disease when in three-copies in people with Down syndrome. Here we show that an extra copy of chromosome 21 genes, other than APP, influences APP/Aβ biology. We crossed Down syndrome mouse models with partial trisomies, to an APP transgenic model and found that extra copies of subgroups of chromosome 21 gene(s) modulate amyloid-β aggregation and APP transgene-associated mortality, independently of changing amyloid precursor protein abundance. Thus, genes on chromosome 21, other than APP, likely modulate Alzheimer's disease in people who have Down syndrome.
    MeSH term(s) Alzheimer Disease/complications ; Alzheimer Disease/genetics ; Amyloid beta-Peptides/chemistry ; Amyloid beta-Peptides/genetics ; Amyloid beta-Protein Precursor/genetics ; Animals ; Brain/pathology ; Chromosomes, Mammalian/genetics ; Disease Models, Animal ; Down Syndrome/complications ; Down Syndrome/genetics ; Mice ; Mice, Transgenic ; Phenotype ; Phosphotransferases/metabolism ; Protein Aggregates ; Protein-Arginine N-Methyltransferases/metabolism ; Segmental Duplications, Genomic ; Seizures/complications ; Seizures/pathology ; Solubility ; Survival Analysis ; Transgenes
    Chemical Substances Amyloid beta-Peptides ; Amyloid beta-Protein Precursor ; Protein Aggregates ; PRMT2 protein, mouse (EC 2.1.1.319) ; Protein-Arginine N-Methyltransferases (EC 2.1.1.319) ; Pdxk protein, mouse (EC 2.7.-) ; Phosphotransferases (EC 2.7.-)
    Language English
    Publishing date 2021-03-11
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-85062-3
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  7. Article ; Online: Publisher Correction: Genetic dissection of down syndrome‑associated alterations in APP/amyloid‑β biology using mouse models.

    Tosh, Justin L / Rhymes, Elena R / Mumford, Paige / Whittaker, Heather T / Pulford, Laura J / Noy, Sue J / Cleverley, Karen / Walker, Matthew C / Tybulewicz, Victor L J / Wykes, Rob C / Fisher, Elizabeth M C / Wiseman, Frances K

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 14966

    Language English
    Publishing date 2021-07-16
    Publishing country England
    Document type Published Erratum
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-94313-2
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  8. Article ; Online: Characterization of optogenetically-induced cortical spreading depression in awake mice using graphene micro-transistor arrays.

    Masvidal-Codina, Eduard / Smith, Trevor M / Rathore, Daman / Gao, Yunan / Illa, Xavi / Prats-Alfonso, Elisabet / Corro, Elena Del / Calia, Andrea Bonaccini / Rius, Gemma / Martin-Fernandez, Iñigo / Guger, Christoph / Reitner, Patrick / Villa, Rosa / Garrido, Jose A / Guimerà-Brunet, Anton / Wykes, Rob C

    Journal of neural engineering

    2021  Volume 18, Issue 5

    Abstract: Objective. ...

    Abstract Objective.
    MeSH term(s) Animals ; Brain ; Cerebral Cortex ; Cortical Spreading Depression ; Graphite ; Mice ; Wakefulness
    Chemical Substances Graphite (7782-42-5)
    Language English
    Publishing date 2021-04-06
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2170901-4
    ISSN 1741-2552 ; 1741-2560
    ISSN (online) 1741-2552
    ISSN 1741-2560
    DOI 10.1088/1741-2552/abecf3
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  9. Article ; Online: Full-bandwidth electrophysiology of seizures and epileptiform activity enabled by flexible graphene microtransistor depth neural probes.

    Bonaccini Calia, Andrea / Masvidal-Codina, Eduard / Smith, Trevor M / Schäfer, Nathan / Rathore, Daman / Rodríguez-Lucas, Elisa / Illa, Xavi / De la Cruz, Jose M / Del Corro, Elena / Prats-Alfonso, Elisabet / Viana, Damià / Bousquet, Jessica / Hébert, Clement / Martínez-Aguilar, Javier / Sperling, Justin R / Drummond, Matthew / Halder, Arnab / Dodd, Abbie / Barr, Katharine /
    Savage, Sinead / Fornell, Jordina / Sort, Jordi / Guger, Christoph / Villa, Rosa / Kostarelos, Kostas / Wykes, Rob C / Guimerà-Brunet, Anton / Garrido, Jose A

    Nature nanotechnology

    2021  Volume 17, Issue 3, Page(s) 301–309

    Abstract: Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1 Hz), typical ... ...

    Abstract Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1 Hz), typical local field potentials (0.1-80 Hz) and higher frequencies (80-600 Hz) using the same recording site would particularly benefit preclinical epilepsy research and could provide clinical biomarkers for improved seizure onset zone delineation. However, commonly used metal microelectrode technology suffers from instabilities that hamper the high fidelity of DC-coupled recordings, which are needed to access signals of very low frequency. In this study we used flexible graphene depth neural probes (gDNPs), consisting of a linear array of graphene microtransistors, to concurrently record DC-shifts and high-frequency neuronal activity in awake rodents. We show here that gDNPs can reliably record and map with high spatial resolution seizures, pre-ictal DC-shifts and seizure-associated spreading depolarizations together with higher frequencies through the cortical laminae to the hippocampus in a mouse model of chemically induced seizures. Moreover, we demonstrate the functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow oscillations in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, and in particular epilepsy research, by allowing stable and chronic DC-coupled recordings.
    MeSH term(s) Animals ; Electroencephalography ; Epilepsy ; Graphite ; Mice ; Microelectrodes ; Rats ; Seizures
    Chemical Substances Graphite (7782-42-5)
    Language English
    Publishing date 2021-12-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2254964-X
    ISSN 1748-3395 ; 1748-3387
    ISSN (online) 1748-3395
    ISSN 1748-3387
    DOI 10.1038/s41565-021-01041-9
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  10. Article: Functional transient receptor potential melastatin 7 channels are critical for human mast cell survival.

    Wykes, Rob C E / Lee, Moonhee / Duffy, S Mark / Yang, Weidong / Seward, Elizabeth P / Bradding, Peter

    Journal of immunology (Baltimore, Md. : 1950)

    2007  Volume 179, Issue 6, Page(s) 4045–4052

    Abstract: Mast cells play a significant role in the pathophysiology of many diverse diseases such as asthma and pulmonary fibrosis. Ca2+ influx is essential for mast cell degranulation and release of proinflammatory mediators, while Mg2+ plays an important role in ...

    Abstract Mast cells play a significant role in the pathophysiology of many diverse diseases such as asthma and pulmonary fibrosis. Ca2+ influx is essential for mast cell degranulation and release of proinflammatory mediators, while Mg2+ plays an important role in cellular homeostasis. The channels supporting divalent cation influx in human mast cells have not been identified, but candidate channels include the transient receptor potential melastatin (TRPM) family. In this study, we have investigated TRPM7 expression and function in primary human lung mast cells (HLMCs) and in the human mast cell lines LAD2 and HMC-1, using RT-PCR, patch clamp electrophysiology, and RNA interference. Whole cell voltage-clamp recordings revealed a nonselective cation current that activated spontaneously following loss of intracellular Mg2+. The current had a nonlinear current-voltage relationship with the characteristic steep outward rectification associated with TRPM7 channels. Reducing external divalent concentration from 3 to 0.3 mM dramatically increased the size of the outward current, whereas the current was markedly inhibited by elevated intracellular Mg2+ (6 mM). Ion substitution experiments revealed cation selectivity and Ca2+ permeability. RT-PCR confirmed the presence of mRNA for TRPM7 in HLMC, LAD2, and HMC-1 cells. Adenoviral-mediated knockdown of TRPM7 in HLMC with short hairpin RNA and in HMC-1 with short interfering RNA markedly reduced TRPM7 currents and induced cell death, an effect that was not rescued by raising extracellular Mg2+. In summary, HLMC and human mast cell lines express the nonselective cation channel TRPM7 whose presence is essential for cell survival.
    MeSH term(s) Adrenergic beta-2 Receptor Agonists ; Cations, Divalent/metabolism ; Cell Death/genetics ; Cell Death/immunology ; Cell Line, Tumor ; Cell Survival/genetics ; Cell Survival/immunology ; Humans ; Lung/cytology ; Lung/immunology ; Lung/metabolism ; Mast Cells/cytology ; Mast Cells/immunology ; Mast Cells/metabolism ; Membrane Potentials/genetics ; Membrane Potentials/immunology ; Patch-Clamp Techniques ; Protein-Serine-Threonine Kinases ; RNA Interference/immunology ; RNA, Messenger/biosynthesis ; Receptors, Adrenergic, beta-2/physiology ; Reverse Transcriptase Polymerase Chain Reaction ; TRPM Cation Channels/biosynthesis ; TRPM Cation Channels/deficiency ; TRPM Cation Channels/genetics ; TRPM Cation Channels/metabolism ; TRPM Cation Channels/physiology ; Transduction, Genetic
    Chemical Substances Adrenergic beta-2 Receptor Agonists ; Cations, Divalent ; RNA, Messenger ; Receptors, Adrenergic, beta-2 ; TRPM Cation Channels ; TRPM6 protein, human ; Protein-Serine-Threonine Kinases (EC 2.7.11.1) ; TRPM7 protein, human (EC 2.7.11.1)
    Language English
    Publishing date 2007-04-29
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3056-9
    ISSN 1550-6606 ; 0022-1767 ; 1048-3233 ; 1047-7381
    ISSN (online) 1550-6606
    ISSN 0022-1767 ; 1048-3233 ; 1047-7381
    DOI 10.4049/jimmunol.179.6.4045
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