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INTRODUCTION: As part of curriculum innovation, the University of North Carolina (UNC) Adams School of Dentistry identified core entrustable professional activities (EPAs) that graduates must demonstrate for practice readiness. This paper describes the development of the UNC EPAs and the perceptions of the general dentistry faculty. METHODS: Upon establishing a blueprint of knowledge, skills, and attitudes of UNC graduates, using a distributed leadership approach, faculty teams developed EPAs focused on the patient care process. The American Dental Education Association Compendium of Clinical Competency Assessments and Commission on Dental Accreditation Standards informed the team's work. Perceptions of the assessment framework were examined using a questionnaire completed by 13 general dentistry faculty considering the importance, accuracy, and agreement of each EPA, associated domains of competence, and encounter management on a 6-point rating scale. RESULTS: Distributed leadership was a useful strategy in EPA development to disperse decision-making and build ownership. Through multiple iterations, four EPAs (assessment, plan of care, collaborative care, and provision of care) with associated sub-EPAs emerged. EPAs included a description, required knowledge and skills, and rubrics for assessment. The general dentistry faculty reported a high level of importance, accuracy, and agreement with EPAs, domains of competence, and encounter management. DISCUSSION: EPAs provide a standardized manner to describe the comprehensive work dentists perform, shifting away from individual competencies. The UNC EPAs provide the foundation for longitudinal measures of competence preparing graduates for independent practice. With limited EPAs frameworks available in dentistry, we aim to inform the development and implementation of EPAs across dental education.
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Educación Basada en Competencias , Internado y Residencia , Humanos , Evaluación Educacional , Curriculum , Competencia Clínica , OdontologíaRESUMEN
Transient receptor potential Ankyrin 1 (TRPA1) is an ion channel expressed by sensory neurons, where it mediates pain signaling. Consequently, it has emerged as a promising target for novel analgesics, yet, to date, no TRPA1 antagonists have been approved for clinical use. In the present translational study, we utilized dermal blood flow changes evoked by TRPA1 agonist cinnamaldehyde as a target engagement biomarker to investigate the in vivo pharmacology of LY3526318, a novel TRPA1 antagonist. In rats, LY3526318 (1, 3, and 10 mg/kg, p.o.) dose-dependently reduced the cutaneous vasodilation typically observed following topical application of 10% v/v cinnamaldehyde. The inhibition was significant at the site of cinnamaldehyde application and also when including an adjacent area of skin. Similarly, in a cohort of 16 healthy human volunteers, LY3526318 administration (10, 30, and 100 mg, p.o.) dose-dependently reduced the elevated blood flow surrounding the site of 10% v/v cinnamaldehyde application, with a trend toward inhibition at the site of application. Comparisons between both species reveal that the effects of LY3526318 on the cinnamaldehyde-induced dermal blood flow are greater in rats relative to humans, even when adjusting for cross-species differences in potency of the compound at TRPA1. Exposure-response relationships suggest that a greater magnitude response may be observed in humans if higher antagonist concentrations could be achieved. Taken together, these results demonstrate that cinnamaldehyde-evoked changes in dermal blood flow can be utilized as a target engagement biomarker for TRPA1 activity and that LY3526318 antagonizes the ion channel both in rats and humans.
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Objective: Standard nerve excitability testing (NET) predominantly assesses Aα- and Aß-fiber function, but a method examining small afferents would be of great interest in pain studies. Here, we examined the properties of a novel perception threshold tracking (PTT) method that preferentially activates Aδ-fibers using weak currents delivered by a novel multipin electrode and compared its reliability with NET. Methods: Eighteen healthy subjects (mean age:34.06⯱â¯2.0) were examined three times with motor and sensory NET and PTT in morning and afternoon sessions on the same day (intra-day reliability) and after a week (inter-day reliability). NET was performed on the median nerve, while PTT stimuli were delivered through a multipin electrode located on the forearm. During PTT, subjects indicated stimulus perception via a button press and the intensity of the current was automatically increased or decreased accordingly by Qtrac software. This allowed changes in the perception threshold to be tracked during strength-duration time constant (SDTC) and threshold electrotonus protocols. Results: The coefficient of variation (CoV) and interclass coefficient of variation (ICC) showed good-excellent reliability for most NET parameters. PTT showed poor reliability for both SDTC and threshold electrotonus parameters. There was a significant correlation between large (sensory NET) and small (PTT) fiber SDTC when all sessions were pooled (râ¯=â¯0.29, pâ¯=â¯0.03). Conclusions: Threshold tracking technique can be applied directly to small fibers via a psychophysical readout, but with the current technique, the reliability is poor. Significance: Further studies are needed to examine whether Aß-fiber SDTC may be a surrogate biomarker for peripheral nociceptive signalling.
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Health education encompasses building health knowledge, but also training skills such as critical thinking, that guide individuals' ability to access, understand and use health information to take care of their own health (WHO, 1998). This study aimed to document expert discussions on the content of an ideal health education curriculum for higher music education (HME) students in the UK, integrating critical thinking. Four interdisciplinary workshops were conducted, where 67 experts in relevant fields discussed the content of four lists created based on literature reviews (cognitive biases, logical fallacies, critical appraisal tools and health topics). Notes taken during the discussions were thematically analysed. Most of the participants thought that the topics and tools were relevant. Two of four identified themes are reported in this paper, which represents the first of a two-part series: (1) critical thinking applied to health; and (2) misconceptions. This is the first attempt to document conversations aimed at using the applied knowledge of key stakeholders to discuss the content of an ideal health education curriculum integrating critical thinking, for conservatoire students.
Professional classical musicians struggle with a range of occupational health issues, but clear guidelines around health education in HME are still missing. This paper reports the first attempt to document a series of four interdisciplinary discussions between 67 experts on (1) the ideal health education content for music students, and (2) the integration of critical thinking as part of music students' health education. Discussions were facilitated by comprehensive lists based on literature reviews. Notes were taken during discussions and were thematically analysed. Four themes were identified, two of which are discussed here: (1) critical thinking applied to health; and (2) misconceptions.
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Música , Humanos , Curriculum , Educación en Salud , Estudiantes , PensamientoRESUMEN
Although health education programmes have been implemented in higher music education (HME) and their evaluations published in peer-reviewed journals, guidelines as to what ought to be included in these programmes are still missing. This study aimed to document expert discussions on the content of an ideal health education curriculum for HME students in the UK, integrating critical thinking. Four interdisciplinary workshops were conducted, where 67 experts in relevant fields took part, and were asked to discuss four lists of topics and concepts created based on literature reviews (cognitive biases, logical fallacies, critical appraisal tools and health topics). Only the list on health topics is relevant here. Notes taken by the participants and ourselves were thematically analysed. Four themes were identified, two of which are reported in this paper: (i) The health education curriculum and (ii) A settings-based approach to health. Part I of this project (published elsewhere) is focussed on the critical thinking content of health education for conservatoire students. The present paper focusses on the ideal health education curriculum and its implications for the wider context of health promotion.
Health education programmes are constantly embedded as part of the higher music education curricula. However, clear guidelines as to what ought to be included in these courses are still missing. This paper reports the first attempt to document a series of four interdisciplinary discussions with 67 experts on the ideal health education content for music students, and its implications for the wider context of health promotion. Discussions were facilitated by comprehensive lists created on the basis of literature reviews. Notes taken by both the participants and ourselves during discussions were thematically analysed. Two of four themes are discussed here: (i) The health education curriculum and (ii) A settings-based approach to health.
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Curriculum , Estudiantes , Humanos , Promoción de la Salud , Estudios InterdisciplinariosRESUMEN
Neurodegenerative disorders are associated with widespread disruption to brain activity and brain rhythms. Some disorders are linked to dysfunction of the membrane-associated protein Tau. Here, we ask how brain rhythms are affected in rTg4510 mouse model of tauopathy, at an early stage of tauopathy (5 months), and at a more advanced stage (8 months). We measured brain rhythms in primary visual cortex in presence or absence of visual stimulation, while monitoring pupil diameter and locomotion to establish behavioral state. At 5 months, we found increased low-frequency rhythms during resting state in tauopathic animals, associated with periods of abnormally increased neural synchronization. At 8 months, this increase in low-frequency rhythms was accompanied by a reduction of power in the gamma range. Our results therefore show that slower rhythms are impaired earlier than gamma rhythms in this model of tauopathy, and suggest that electrophysiological measurements can track the progression of tauopathic neurodegeneration.
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BACKGROUND: IMI2-PainCare-BioPain-RCT2 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on specific compartments of the nociceptive system that could serve to accelerate the future development of analgesics. IMI2-PainCare-BioPain-RCT2 will focus on human spinal cord and brainstem activity using biomarkers derived from non-invasive neurophysiological measurements. METHODS: This is a multisite, single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Neurophysiological biomarkers of spinal and brainstem activity (the RIII flexion reflex, the N13 component of somatosensory evoked potentials (SEP) and the R2 component of the blink reflex) will be recorded before and at three distinct time points after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol), and placebo, given as a single oral dose in separate study periods. Medication effects on neurophysiological measures will be assessed in a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin), and in a non-sensitized normal condition. Patient-reported outcome measures (pain ratings and predictive psychological traits) will also be collected; and blood samples will be taken for pharmacokinetic modelling. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between the two primary endpoints, namely the percentage amplitude changes of the RIII area and N13 amplitude under tapentadol. Remaining treatment arm effects on RIII, N13 and R2 recovery cycle are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modelling are exploratory. DISCUSSION: The RIII component of the flexion reflex is a pure nociceptive spinal reflex widely used for investigating pain processing at the spinal level. It is sensitive to different experimental pain models and to the antinociceptive activity of drugs. The N13 is mediated by large myelinated non-nociceptive fibers and reflects segmental postsynaptic response of wide dynamic range dorsal horn neurons at the level of cervical spinal cord, and it could be therefore sensitive to the action of drugs specifically targeting the dorsal horn. The R2 reflex is mediated by large myelinated non-nociceptive fibers, its circuit consists of a polysynaptic chain lying in the reticular formation of the pons and medulla. The recovery cycle of R2 is widely used for assessing brainstem excitability. For these reasons, IMI2-PainCare-BioPain-RCT2 hypothesizes that spinal and brainstem neurophysiological measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification. TRIAL REGISTRATION: This trial was registered on 02 February 2019 in EudraCT ( 2019-000755-14 ).
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Analgésicos , Dolor , Médula Espinal , Analgésicos/farmacología , Biomarcadores , Tronco Encefálico , Estudios Cruzados , Método Doble Ciego , Voluntarios Sanos , Humanos , Lacosamida , Estudios Multicéntricos como Asunto , Dolor/tratamiento farmacológico , Pregabalina , Ensayos Clínicos Controlados Aleatorios como Asunto , TapentadolRESUMEN
There is an urgent need for analgesics with improved efficacy, especially in neuropathic and other chronic pain conditions. Unfortunately, in recent decades, many candidate analgesics have failed in clinical phase II or III trials despite promising preclinical results. Translational assessment tools to verify engagement of pharmacological targets and actions on compartments of the nociceptive system are missing in both rodents and humans. Through the Innovative Medicines Initiative of the European Union and EFPIA, a consortium of researchers from academia and the pharmaceutical industry was established to identify and validate a set of functional biomarkers to assess drug-induced effects on nociceptive processing at peripheral, spinal and supraspinal levels using electrophysiological and functional neuroimaging techniques. Here, we report the results of a systematic literature search for pharmacological probes that allow for validation of these biomarkers. Of 26 candidate substances, only 7 met the inclusion criteria: evidence for nociceptive system modulation, tolerability, availability in oral form for human use and absence of active metabolites. Based on pharmacokinetic characteristics, three were selected for a set of crossover studies in rodents and healthy humans. All currently available probes act on more than one compartment of the nociceptive system. Once validated, biomarkers of nociceptive signal processing, combined with a pharmacometric modelling, will enable a more rational approach to selecting dose ranges and verifying target engagement. Combined with advances in classification of chronic pain conditions, these biomarkers are expected to accelerate analgesic drug development.
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Analgésicos , Biomarcadores Farmacológicos , Desarrollo de Medicamentos , Analgésicos/farmacología , Analgésicos/uso terapéutico , Dolor Crónico/tratamiento farmacológico , Desarrollo de Medicamentos/métodos , Desarrollo de Medicamentos/normas , Humanos , Neuralgia/tratamiento farmacológico , Reproducibilidad de los Resultados , Columna Vertebral/efectos de los fármacos , Columna Vertebral/inervaciónRESUMEN
Following the adoption of competency-based education in dentistry in the 1990s, entrustable professional activities (EPAs) were introduced in the field of medicine in the mid-2000s to help educators better determine the competence of trainees. More recently, the field of dental education has begun exploring EPAs as a framework for assessing competence while ensuring compliance with accreditation standards. This paper explores one dental school's process of preparing for implementation of a major curriculum change using an EPA assessment framework, shifting away from the use of singular assessments for competency determination to a global and longitudinal approach using a constellation of data to determine practice readiness. This paper describes how the EPA framework was developed, including the complementary capacities, assessment tool development and programming, and data reporting to follow learner progression and determine practice readiness. We discuss lessons learned leading up to implementation, and we position this perspective as a space to describe opportunities and complexities to consider when using a longitudinal assessment system. We attend to the tension between the current language of Commission of Dental Accreditation Standards as "competencies" and the evolving conversation of operationalizing EPAs while addressing accreditation Standards. To do this, we describe the process of finalizing our EPA framework and preparing for initial implementation in a new curriculum.
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Internado y Residencia , Humanos , Competencia Clínica , Educación Basada en Competencias , Curriculum , AcreditaciónRESUMEN
BACKGROUND: Few new drugs have been developed for chronic pain. Drug development is challenged by uncertainty about whether the drug engages the human target sufficiently to have a meaningful pharmacodynamic effect. IMI2-PainCare-BioPain-RCT1 is one of four similarly designed studies that aim to link different functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics. This study focusses on biomarkers derived from nerve excitability testing (NET) using threshold tracking of the peripheral nervous system. METHODS: This is a multisite single-dose, subject and assessor-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD), and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from NET of large sensory and motor fibers and small sensory fibers using perception threshold tracking will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose with at least 1 week apart. Motor and sensory NET will be assessed on the right wrist in a non-sensitized normal condition while perception threshold tracking will be performed bilaterally on both non-sensitized and sensitized forearm skin. Cutaneous high-frequency electrical stimulation is used to induce hyperalgesia. Blood samples will be taken for pharmacokinetic purposes and pain ratings as well as predictive psychological traits will be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split across the two primary outcomes: strength-duration time constant (SDTC; a measure of passive membrane properties and nodal persistent Na+ conductance) of large sensory fibers and SDTC of large motor fibers comparing lacosamide and placebo. The key secondary endpoint is the SDTC measured in small sensory fibers. Remaining treatment arm effects on key NET outcomes and PK modelling are other prespecified secondary or exploratory analyses. DISCUSSION: Measurements of NET using threshold tracking protocols are sensitive to membrane potential at the site of stimulation. Sets of useful indices of axonal excitability collectively may provide insights into the mechanisms responsible for membrane polarization, ion channel function, and activity of ionic pumps during the process of impulse conduction. IMI2-PainCare-BioPain-RCT1 hypothesizes that NET can serve as biomarkers of target engagement of analgesic drugs in this compartment of the nociceptive system for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification. TRIAL REGISTRATION: This trial was registered 25/06/2019 in EudraCT ( 2019-000942-36 ).
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Dolor , Nervios Periféricos , Biomarcadores , Método Doble Ciego , Voluntarios Sanos , Humanos , Lacosamida , Estudios Multicéntricos como Asunto , Pregabalina , Ensayos Clínicos Controlados Aleatorios como Asunto , TapentadolRESUMEN
BACKGROUND: Pain is a complex polygenic trait whose common genetic underpinnings are relatively ill-defined due in part to challenges in measuring pain as a phenotype. Pain sensitivity can be quantified, but this is difficult to perform at the scale required for genome wide association studies (GWAS). Existing GWAS of pain have identified surprisingly few loci involved in nociceptor function which contrasts strongly with rare monogenic pain states. This suggests a lack of resolution with current techniques. We propose an adaptive methodology within a recall-by-genotype (RbG) framework using detailed phenotyping to screen minor alleles in a candidate 'nociceptor' gene in an attempt to estimate their genetic contribution to pain. METHODS/DESIGN: Participants of the Avon Longitudinal Study of Parents and Children will be recalled on the basis of genotype at five common non-synonomous SNPs in the 'nociceptor' gene transient receptor potential ankylin 1 (TRPA1). Those homozygous for the common alleles at each of the five SNPs will represent a control group. Individuals homozygous for the minor alleles will then be recruited in a series of three sequential test groups. The outcome of a pre-planned early assessment (interim) of the current test group will determine whether to continue recruitment or switch to the next test group. Pain sensitivity will be assessed using quantitative sensory testing (QST) before and after topical application of 10% cinnamaldehyde (a TRPA1 agonist). DISCUSSION: The design of this adaptive RbG study offers efficiency in the assessment of associations between genetic variation at TRPA1 and detailed pain phenotypes. The possibility to change the test group in response to preliminary data increases the likelihood to observe smaller effect sizes relative to a conventional multi-armed design, as well as reducing futile testing of participants where an effect is unlikely to be observed. This specific adaptive RbG design aims to uncover the influence of common TRPA1 variants on pain sensation but can be applied to any hypothesis-led genotype study where costly and time intensive investigation is required and / or where there is large uncertainty around the expected effect size. TRIAL REGISTRATION: ISRCTN, ISRCTN16294731. Retrospectively registered 25th November 2021.
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Estudio de Asociación del Genoma Completo , Polimorfismo de Nucleótido Simple , Genotipo , Humanos , Estudios Longitudinales , Dolor/genética , Fenotipo , Canal Catiónico TRPA1/genéticaRESUMEN
Alzheimer's disease and other dementias are thought to underlie a progressive impairment of neural plasticity. Previous work in mouse models of Alzheimer's disease shows pronounced changes in artificially-induced plasticity in hippocampus, perirhinal and prefrontal cortex. However, it is not known how degeneration disrupts intrinsic forms of brain plasticity. Here we characterised the impact of tauopathy on a simple form of intrinsic plasticity in the visual system, which allowed us to track plasticity at both long (days) and short (minutes) timescales. We studied rTg4510 transgenic mice at early stages of tauopathy (5 months) and a more advanced stage (8 months). We recorded local field potentials in the primary visual cortex while animals were repeatedly exposed to a stimulus over 9 days. We found that both short- and long-term visual plasticity were already disrupted at early stages of tauopathy, and further reduced in older animals, such that it was abolished in mice expressing mutant tau. Additionally, visually evoked behaviours were disrupted in both younger and older mice expressing mutant tau. Our results show that visual cortical plasticity and visually evoked behaviours are disrupted in the rTg4510 model of tauopathy. This simple measure of plasticity may help understand how tauopathy disrupts neural circuits, and offers a translatable platform for detection and tracking of the disease.
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Enfermedad de Alzheimer/fisiopatología , Plasticidad Neuronal/fisiología , Corteza Visual/fisiología , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones TransgénicosRESUMEN
Current therapies for Alzheimer's disease seek to correct for defective cholinergic transmission by preventing the breakdown of acetylcholine through inhibition of acetylcholinesterase, these however have limited clinical efficacy. An alternative approach is to directly activate cholinergic receptors responsible for learning and memory. The M1-muscarinic acetylcholine (M1) receptor is the target of choice but has been hampered by adverse effects. Here we aimed to design the drug properties needed for a well-tolerated M1-agonist with the potential to alleviate cognitive loss by taking a stepwise translational approach from atomic structure, cell/tissue-based assays, evaluation in preclinical species, clinical safety testing, and finally establishing activity in memory centers in humans. Through this approach, we rationally designed the optimal properties, including selectivity and partial agonism, into HTL9936-a potential candidate for the treatment of memory loss in Alzheimer's disease. More broadly, this demonstrates a strategy for targeting difficult GPCR targets from structure to clinic.
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Enfermedad de Alzheimer/tratamiento farmacológico , Diseño de Fármacos , Receptor Muscarínico M1/agonistas , Anciano , Anciano de 80 o más Años , Envejecimiento/patología , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/patología , Secuencia de Aminoácidos , Animales , Presión Sanguínea/efectos de los fármacos , Células CHO , Inhibidores de la Colinesterasa/farmacología , Cricetulus , Cristalización , Modelos Animales de Enfermedad , Perros , Donepezilo/farmacología , Electroencefalografía , Femenino , Células HEK293 , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Ratones Endogámicos C57BL , Modelos Moleculares , Simulación de Dinámica Molecular , Degeneración Nerviosa/complicaciones , Degeneración Nerviosa/patología , Primates , Ratas , Receptor Muscarínico M1/química , Transducción de Señal , Homología Estructural de ProteínaRESUMEN
OBJECTIVES: Although somatosensory evoked potentials (SEPs) after median nerve stimulation are widely used in clinical practice, the dorsal horn generator of the N13 SEP spinal component is not clearly understood. To verify whether wide dynamic range neurons in the dorsal horn of the spinal cord are involved in the generation of the N13 SEP, we tested the effect of heterotopic noxious conditioning stimulation, which modulates wide dynamic range neurons, on N13 SEP in healthy humans. METHODS: In 12 healthy subjects, we performed the cold pressor test on the left foot as a heterotopic noxious conditioning stimulus to modulate wide dynamic range neurons. To verify the effectiveness of heterotopic noxious conditioning stimulation, we tested the pressure pain threshold at the thenar muscles of the right hand and recorded SEPs after right median nerve stimulation before, during and after the cold pressor test. RESULTS: The cold pressor test increased pressure pain threshold by 15% (p = 0.04). During the cold pressor test, the amplitude of the N13 component was significantly lower than that recorded at baseline (by 25%, p = 0.04). DISCUSSION: In this neurophysiological study in healthy humans, we showed that a heterotopic noxious conditioning stimulus significantly reduced N13 SEP amplitude. This finding suggests that the N13 SEP might be generated by the segmental postsynaptic response of dorsal horn wide dynamic range neurons.
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Potenciales Evocados Somatosensoriales , Nervio Mediano , Estimulación Eléctrica , Mano , Humanos , Neuronas , Médula EspinalRESUMEN
BACKGROUND: IMI2-PainCare-BioPain-RCT3 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics, by providing a quantitative understanding between drug exposure and effects of the drug on nociceptive signal processing in human volunteers. IMI2-PainCare-BioPain-RCT3 will focus on biomarkers derived from non-invasive electroencephalographic (EEG) measures of brain activity. METHODS: This is a multisite single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from scalp EEG measurements (laser-evoked brain potentials [LEPs], pinprick-evoked brain potentials [PEPs], resting EEG) will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose in separate study periods. Medication effects will be assessed concurrently in a non-sensitized normal condition and a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin). Patient-reported outcomes will also be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between LEP and PEP under tapentadol. Remaining treatment arm effects on LEP or PEP or effects on EEG are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modeling are exploratory. DISCUSSION: LEPs and PEPs are brain responses related to the selective activation of thermonociceptors and mechanonociceptors. Their amplitudes are dependent on the responsiveness of these nociceptors and the state of the pathways relaying nociceptive input at the level of the spinal cord and brain. The magnitude of resting EEG oscillations is sensitive to changes in brain network function, and some modulations of oscillation magnitude can relate to perceived pain intensity, variations in vigilance, and attentional states. These oscillations can also be affected by analgesic drugs acting on the central nervous system. For these reasons, IMI2-PainCare-BioPain-RCT3 hypothesizes that EEG-derived measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification. TRIAL REGISTRATION: This trial was registered 25/06/2019 in EudraCT ( 2019%2D%2D001204-37 ).
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Electroencefalografía , Dolor , Biomarcadores , Estudios Cruzados , Método Doble Ciego , Voluntarios Sanos , Humanos , Lacosamida , Dimensión del Dolor , Pregabalina/efectos adversos , TapentadolRESUMEN
Dementia is associated with severe spatial memory deficits which arise from dysfunction in hippocampal and parahippocampal circuits. For spatially sensitive neurons, such as grid cells, to faithfully represent the environment these circuits require precise encoding of direction and velocity information. Here, we have probed the firing rate coding properties of neurons in medial entorhinal cortex (MEC) in a mouse model of tauopathy. We find that grid cell firing patterns are largely absent in rTg4510 mice, while head-direction tuning remains largely intact. Conversely, neural representation of running speed information was significantly disturbed, with smaller proportions of MEC cells having firing rates correlated with locomotion in rTg4510 mice. Additionally, the power of local field potential oscillations in the theta and gamma frequency bands, which in wild-type mice are tightly linked to running speed, was invariant in rTg4510 mice during locomotion. These deficits in locomotor speed encoding likely severely impact path integration systems in dementia.
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Corteza Entorrinal/citología , Células de Red/fisiología , Actividad Motora/fisiología , Periodicidad , Tauopatías/patología , Animales , Corteza Entorrinal/fisiología , RatonesRESUMEN
Dynamic gain and loss of synapses is fundamental to healthy brain function. While Alzheimer's Disease (AD) treatment strategies have largely focussed on beta-amyloid and tau protein pathologies, the synapse itself may also be a critical endpoint to consider regarding disease modification. Disruption of mechanisms of neuronal plasticity, eventually resulting in a net loss of synapses, is implicated as an early pathological event in AD. Synaptic dysfunction therefore may be a final common biological mechanism linking protein pathologies to disease symptoms. This review summarizes evidence supporting the idea of early neuroplastic deficits being prevalent in AD. Changes in synaptic density can occur before overt neurodegeneration and should not be considered to uniformly decrease over the course of the disease. Instead, synaptic levels are influenced by an interplay between processes of degeneration and atrophy, and those of maintenance and compensation at regional and network levels. How these neuroplastic changes are driven by amyloid and tau pathology are varied. A mixture of direct effects of amyloid and tau on synaptic integrity, as well as indirect effects on processes such as inflammation and neuronal energetics are likely to be at play here. Focussing on the synapse and mechanisms of neuroplasticity as therapeutic opportunities in AD raises some important conceptual and strategic issues regarding translational research, and how preclinical research can inform clinical studies. Nevertheless, substrates of neuroplasticity represent an emerging complementary class of drug target that would aim to normalize synapse dynamics and restore cognitive function in the AD brain and in other neurodegenerative diseases.
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KEY POINTS: The medial entorhinal cortex (mEC) has an important role in initiation and propagation of seizure activity. Several anatomical relationships exist in neurophysiological properties of mEC neurons; however, in the context of hyperexcitability, previous studies often considered it as a homogeneous structure. Using multi-site extracellular recording techniques, ictal-like activity was observed along the dorso-ventral axis of the mEC in vitro in response to various ictogenic stimuli. This originated predominantly from ventral areas, spreading to dorsal mEC with a surprisingly slow velocity. Modulation of inhibitory tone was capable of changing the slope of ictal initiation, suggesting seizure propagation behaviours are highly dependent on levels of GABAergic function in this region. A distinct disinhibition model also showed, in the absence of inhibition, a prevalence for interictal-like initiation in ventral mEC, reflecting the intrinsic differences in mEC neurons. These findings suggest the ventral mEC is more prone to hyperexcitable discharge than the dorsal mEC, which may be relevant under pathological conditions. ABSTRACT: The medial entorhinal cortex (mEC) has an important role in the generation and propagation of seizure activity. The organization of the mEC is such that a number of dorso-ventral relationships exist in neurophysiological properties of neurons. These range from intrinsic and synaptic properties to density of inhibitory connectivity. We examined the influence of these gradients on generation and propagation of epileptiform activity in the mEC. Using a 16-shank silicon probe array to record along the dorso-ventral axis of the mEC in vitro, we found 4-aminopyridine application produces ictal-like activity originating predominantly in ventral areas. This activity spreads to dorsal mEC at a surprisingly slow velocity (138 µm s-1 ), while cross-site interictal-like activity appeared relatively synchronous. We propose that ictal propagation is constrained by differential levels of GABAergic control since increasing (diazepam) or decreasing (Ro19-4603) GABAA receptor activation, respectively, reduced or increased the slope of ictal initiation. The observation that ictal activity is predominately generated in ventral mEC was replicated using a separate 0-Mg2+ model of epileptiform activity in vitro. By using a distinct disinhibition model (co-application of kainate and picrotoxin) we show that additional physiological features (for example intrinsic properties of mEC neurons) still produce a prevalence for interictal-like initiation in ventral mEC. These findings suggest that the ventral mEC is more likely to initiate hyperexcitable discharges than the dorsal mEC, and that seizure propagation is highly dependent on levels of GABAergic expression across the mEC.