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Comment on 'Accumbens cholinergic interneurons dynamically promote dopamine release and enable motivation'. eLife 2024; 13:e95694. [PMID: 38748470 PMCID: PMC11095934 DOI: 10.7554/elife.95694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Acetylcholine is widely believed to modulate the release of dopamine in the striatum of mammals. Experiments in brain slices clearly show that synchronous activation of striatal cholinergic interneurons is sufficient to drive dopamine release via axo-axonal stimulation of nicotinic acetylcholine receptors. However, evidence for this mechanism in vivo has been less forthcoming. Mohebi, Collins and Berke recently reported that, in awake behaving rats, optogenetic activation of striatal cholinergic interneurons with blue light readily evokes dopamine release measured with the red fluorescent sensor RdLight1 (Mohebi et al., 2023). Here, we show that blue light alone alters the fluorescent properties of RdLight1 in a manner that may be misconstrued as phasic dopamine release, and that this artefactual photoactivation can account for the effects attributed to cholinergic interneurons. Our findings indicate that measurements of dopamine using the red-shifted fluorescent sensor RdLight1 should be interpreted with caution when combined with optogenetics. In light of this and other publications that did not observe large acetylcholine-evoked dopamine transients in vivo, the conditions under which such release occurs in behaving animals remain unknown.
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Mesolimbic dopamine ramps reflect environmental timescales. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587103. [PMID: 38659749 PMCID: PMC11042231 DOI: 10.1101/2024.03.27.587103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Mesolimbic dopamine activity occasionally exhibits ramping dynamics, reigniting debate on theories of dopamine signaling. This debate is ongoing partly because the experimental conditions under which dopamine ramps emerge remain poorly understood. Here, we show that during Pavlovian and instrumental conditioning, mesolimbic dopamine ramps are only observed when the inter-trial interval is short relative to the trial period. These results constrain theories of dopamine signaling and identify a critical variable determining the emergence of dopamine ramps.
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Dopamine transients follow a striatal gradient of reward time horizons. Nat Neurosci 2024; 27:737-746. [PMID: 38321294 PMCID: PMC11001583 DOI: 10.1038/s41593-023-01566-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 12/21/2023] [Indexed: 02/08/2024]
Abstract
Animals make predictions to guide their behavior and update those predictions through experience. Transient increases in dopamine (DA) are thought to be critical signals for updating predictions. However, it is unclear how this mechanism handles a wide range of behavioral timescales-from seconds or less (for example, if singing a song) to potentially hours or more (for example, if hunting for food). Here we report that DA transients in distinct rat striatal subregions convey prediction errors based on distinct time horizons. DA dynamics systematically accelerated from ventral to dorsomedial to dorsolateral striatum, in the tempo of spontaneous fluctuations, the temporal integration of prior rewards and the discounting of future rewards. This spectrum of timescales for evaluative computations can help achieve efficient learning and adaptive motivation for a broad range of behaviors.
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Lights, fiber, action! A primer on in vivo fiber photometry. Neuron 2024; 112:718-739. [PMID: 38103545 PMCID: PMC10939905 DOI: 10.1016/j.neuron.2023.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/16/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Fiber photometry is a key technique for characterizing brain-behavior relationships in vivo. Initially, it was primarily used to report calcium dynamics as a proxy for neural activity via genetically encoded indicators. This generated new insights into brain functions including movement, memory, and motivation at the level of defined circuits and cell types. Recently, the opportunity for discovery with fiber photometry has exploded with the development of an extensive range of fluorescent sensors for biomolecules including neuromodulators and peptides that were previously inaccessible in vivo. This critical advance, combined with the new availability of affordable "plug-and-play" recording systems, has made monitoring molecules with high spatiotemporal precision during behavior highly accessible. However, while opening exciting new avenues for research, the rapid expansion in fiber photometry applications has occurred without coordination or consensus on best practices. Here, we provide a comprehensive guide to help end-users execute, analyze, and suitably interpret fiber photometry studies.
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Comment on 'Accumbens cholinergic interneurons dynamically promote dopamine release and enable motivation'. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.27.573485. [PMID: 38260459 PMCID: PMC10802245 DOI: 10.1101/2023.12.27.573485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Acetylcholine is widely believed to modulate the release of dopamine in the striatum of mammals. Experiments in brain slices clearly show that synchronous activation of striatal cholinergic interneurons is sufficient to drive dopamine release via axo-axonal stimulation of nicotinic acetylcholine receptors. However, evidence for this mechanism in vivo has been less forthcoming. A recent paper in eLife (Mohebi et al., 2023) reported that, in awake behaving rats, optogenetic activation of striatal cholinergic interneurons with blue light readily evokes dopamine release measured with the red fluorescent sensor RdLight1. Here, we show that blue light alone alters the fluorescent properties of RdLight1 in a manner that may be misconstrued as phasic dopamine release, and that this artefactual photoactivation can account for the effects attributed to cholinergic interneurons. Our findings indicate that measurements of dopamine using the red-shifted fluorescent sensor RdLight1 should be interpreted with caution when combined with optogenetics. In light of this and other publications that did not observe large acetylcholine-evoked dopamine transients in vivo, the conditions under which such release occurs in behaving animals remain unknown.
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Selective encoding of reward predictions and prediction errors by globus pallidus subpopulations. Curr Biol 2023; 33:4124-4135.e5. [PMID: 37703876 PMCID: PMC10591972 DOI: 10.1016/j.cub.2023.08.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/04/2023] [Accepted: 08/15/2023] [Indexed: 09/15/2023]
Abstract
Basal ganglia (BG) circuits help guide and invigorate actions using predictions of future rewards (values). Within the BG, the globus pallidus pars externa (GPe) may play an essential role in aggregating and distributing value information. We recorded from the GPe in unrestrained rats performing both Pavlovian and instrumental tasks to obtain rewards and distinguished neuronal subtypes by their firing properties across the wake/sleep cycle and optogenetic tagging. In both tasks, the parvalbumin-positive (PV+), faster-firing "prototypical" neurons showed strong, sustained modulation by value, unlike other subtypes, including the "arkypallidal" cells that project back to striatum. Furthermore, we discovered that a distinct minority (7%) of GP cells display slower, pacemaker-like firing and encode reward prediction errors (RPEs) almost identically to midbrain dopamine neurons. These cell-specific forms of GPe value representation help define the circuit mechanisms by which the BG contribute to motivation and reinforcement learning.
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Accumbens cholinergic interneurons dynamically promote dopamine release and enable motivation. eLife 2023; 12:e85011. [PMID: 37272423 PMCID: PMC10259987 DOI: 10.7554/elife.85011] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 05/30/2023] [Indexed: 06/06/2023] Open
Abstract
Motivation to work for potential rewards is critically dependent on dopamine (DA) in the nucleus accumbens (NAc). DA release from NAc axons can be controlled by at least two distinct mechanisms: (1) action potentials propagating from DA cell bodies in the ventral tegmental area (VTA), and (2) activation of β2* nicotinic receptors by local cholinergic interneurons (CINs). How CIN activity contributes to NAc DA dynamics in behaving animals is not well understood. We monitored DA release in the NAc Core of awake, unrestrained rats using the DA sensor RdLight1, while simultaneously monitoring or manipulating CIN activity at the same location. CIN stimulation rapidly evoked DA release, and in contrast to slice preparations, this DA release showed no indication of short-term depression or receptor desensitization. The sound of unexpected food delivery evoked a brief joint increase in CIN population activity and DA release, with a second joint increase as rats approached the food. In an operant task, we observed fast ramps in CIN activity during approach behaviors, either to start the trial or to collect rewards. These CIN ramps co-occurred with DA release ramps, without corresponding changes in the firing of lateral VTA DA neurons. Finally, we examined the effects of blocking CIN influence over DA release through local NAc infusion of DHβE, a selective antagonist of β2* nicotinic receptors. DHβE dose-dependently interfered with motivated approach decisions, mimicking the effects of a DA antagonist. Our results support a key influence of CINs over motivated behavior via the local regulation of DA release.
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Marked point process representation of oscillatory dynamics underlying working memory. J Neural Eng 2021; 18. [DOI: 10.1088/1741-2552/abd577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 12/21/2020] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. Computational models of neural activity at the meso-scale suggest the involvement of discrete oscillatory bursts as constructs of cognitive processing during behavioral tasks. Classical signal processing techniques that attempt to infer neural correlates of behavior from meso-scale activity employ spectral representations of the signal, exploiting power spectral density techniques and time–frequency (T–F) energy distributions to capture band power features. However, such analyses demand more specialized methods that incorporate explicitly the concepts of neurophysiological signal generation and time resolution in the tens of milliseconds. This paper focuses on working memory (WM), a complex cognitive process involved in encoding, storing and retrieving sensory information, which has been shown to be characterized by oscillatory bursts in the beta and gamma band. Employing a generative model for oscillatory dynamics, we present a marked point process (MPP) representation of bursts during memory creation and readout. We show that the markers of the point process quantify specific neural correlates of WM. Approach. We demonstrate our results on field potentials recorded from the prelimbic and secondary motor cortices of three rats while performing a WM task. The generative model for single channel, band-passed traces of field potentials characterizes with high-resolution, the timings and amplitudes of transient neuromodulations in the high gamma (80–150 Hz, γ) and beta (10–30 Hz, β) bands as an MPP. We use standard hypothesis testing methods on the MPP features to check for significance in encoding of task variables, sensory stimulus and executive control while comparing encoding capabilities of our model with other T–F methods. Main Results. Firstly, the advantages of an MPP approach in deciphering encoding mechanisms at the meso-scale is demonstrated. Secondly, the nature of state encoding by neuromodulatory events is determined. Third, we demonstrate the necessity of a higher time resolution alternative to conventionally employed T–F methods. Finally, our results underscore the novelty in interpreting oscillatory dynamics encompassed by the marked features of the point process. Significance. An MPP representation of meso-scale activity not just enables a rich, high-resolution parameter space for analysis but also presents a novel tool for diverse neural applications.
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Combined approach using circular intensity differential scattering microscopy under phasor map data analysis. APPLIED OPTICS 2021; 60:1558-1565. [PMID: 33690489 DOI: 10.1364/ao.417677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
Circular intensity differential scattering (CIDS) is based on the analysis of circular polarized light scattering and has been proven to be an interesting label-free microscopy technique sensitive to the chiral organization at the submicroscopic level. However, this approach averages the localized contrasts related to the sample polarimetric properties in the illumination volume. Additionally, the detection sensitivity suffers from the confinement of the mixture of structures, and it becomes an arduous task to discriminate the source of the signal. In this work, we show that a phasor map approach combined with CIDS microscopy has provided an intuitive view of the sample organization to recognize the presence of different molecular species in the illumination volume. The data represented in terms of polarization response mapped to a single point called a phasor also have the potential to pave the way for the analysis of large data sets. We validated this method by numerical simulations and compared the results with that of experimental data of optical devices of reference.
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Resolution Improvement in CIDS Super-Resolution Microscopy using a Phasor Plot Approach. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Multispectral Stokes/Mueller Detection Module for Multiphoton/Fluorescence Confocal Scanning Imaging Microscopy. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.2200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Development of Sodium Sulfate Induced Water Based Dispersive Liquid–Liquid Microextraction for the Extraction of Four Tricyclic Antidepressants in Urine Samples Prior to Their Determination by Gas Chromatography–Mass Spectrometry. PHARMACEUTICAL SCIENCES 2020. [DOI: 10.34172/ps.2020.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: Because of the narrow therapeutic range of tricyclic antidepressant drugs, their determination in biological samples is of great importance. In this work, a fast and environment friendly sample pretreatment method based on a dispersive liquid–liquid microextraction was developed for the extraction and preconcentration of four tricyclic antidepressants including nortriptyline, amitriptyline, desipramine, and clomipramine in urine prior to their determinations by gas chromatography–mass spectrometry. Methods: In the suggested method, an appropriate mixture of Na2SO4 solution (as phase separation agent and disperser) containing isopropanol (extraction solvent) is rapidly injected into an alkaline aqueous sample solution containing Na2SO4 and the analytes. As a result, a cloudy mixture is formed and the tiny droplets of the extractant containing the extracted analytes are collected on the surface of the aqueous phase after centrifuging. Finally, an aliquot of the collected organic phase is removed and injected into the separation system for the quantitative analysis. Results: Under the optimum conditions, the enrichment factors and extraction recoveries were in the ranges of 380–440 and 76–88%, respectively. The limits of detection and quantification were obtained in the ranges of 11–24, and 41–75 ng/L, respectively. The relative standard deviations of the proposed method were ≤ 6.1% for intra– (n=6) and inter–day (n=4) precisions at a concentration of 100 ng/L of each analyte. Conclusion: The introduced method was satisfactorily utilized for the simultaneous determination of the selected tricyclic antidepressant drugs in the patient’s urine samples.
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Monogenic Auto-inflammatory Syndromes: A Review of the Literature. IRANIAN JOURNAL OF ALLERGY, ASTHMA, AND IMMUNOLOGY 2016; 15:430-444. [PMID: 28129677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Accepted: 12/30/2016] [Indexed: 06/06/2023]
Abstract
Auto-inflammatory syndromes are a new group of distinct hereditable disorders characterized by episodes of seemingly unprovoked inflammation (most commonly in skin, joints, gut, and eye), the absence of a high titer of auto-antibodies or auto-reactive T cells, and an inborn error of innate immunity. A narrative literature review was carried out of studies related to auto-inflammatory syndromes to discuss the pathogenesis and clinical manifestation of these syndromes. This review showed that the main monogenic auto-inflammatory syndromes are familial Mediterranean fever (FMF), mevalonate kinase deficiency (MKD), Blau syndrome, TNF receptor-associated periodic syndrome (TRAPS), cryopyrin-associated periodic syndrome (CAPS), and pyogenic arthritis with pyoderma gangrenosum and acne (PAPA). The data suggest that correct diagnosis and treatment of monogenic auto-inflammatory diseases relies on the physicians' awareness. Therefore, understanding of the underlying pathogenic mechanisms of auto-inflammatory syndromes, and especially the fact that these disorders are mediated by IL-1 secretion stimulated by monocytes and macrophages, facilitated significant progress in patient management.
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PP048-SUN: Body Composition Parameters by Abdominal CT-Scan in Elderly People: Prognostic Value. Clin Nutr 2014. [DOI: 10.1016/s0261-5614(14)50090-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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A fully automated rodent conditioning protocol for sensorimotor integration and cognitive control experiments. J Vis Exp 2014. [PMID: 24798582 DOI: 10.3791/51128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Rodents have been traditionally used as a standard animal model in laboratory experiments involving a myriad of sensory, cognitive, and motor tasks. Higher cognitive functions that require precise control over sensorimotor responses such as decision-making and attentional modulation, however, are typically assessed in nonhuman primates. Despite the richness of primate behavior that allows multiple variants of these functions to be studied, the rodent model remains an attractive, cost-effective alternative to primate models. Furthermore, the ability to fully automate operant conditioning in rodents adds unique advantages over the labor intensive training of nonhuman primates while studying a broad range of these complex functions. Here, we introduce a protocol for operantly conditioning rats on performing working memory tasks. During critical epochs of the task, the protocol ensures that the animal's overt movement is minimized by requiring the animal to 'fixate' until a Go cue is delivered, akin to nonhuman primate experimental design. A simple two alternative forced choice task is implemented to demonstrate the performance. We discuss the application of this paradigm to other tasks.
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Abstract
A fundamental goal in systems neuroscience is to assess the individual as well as the synergistic roles of single neurons in a recorded ensemble as they relate to an observed behavior. A mandatory step to achieve this goal is to sort spikes in an extracellularly recorded mixture that belong to individual neurons through feature extraction and clustering techniques. Here, we propose an approach for approximating the often nonlinear and time varying decision boundaries between spike-derived feature classes based on a simple, yet optimal thresholding mechanism. Because thresholding is a binary classifier, we show that the complex nonlinear decision boundaries required for spike class discrimination can be achieved by adequately fusing a set of weak binary classifiers. The thresholds for these binary classifiers are adaptively estimated through a learning algorithm that maximizes the separability between the sparsely represented classes. Based on our previous work, the approach substantially reduces the computational complexity of extracting, aligning and sorting multiple single unit activity early in the data stream. Here, we also show its ability to track changes in spike features over extended periods of time, making it highly suitable for basic neuroscience studies as well as for implementation in miniaturized, fully implantable electronics in brain-machine interface applications.
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A Randomized Controlled Trial on the Hemostasis of Femoral Artery Using Topical Hemostatic Agent. Clin Appl Thromb Hemost 2012; 18:501-5. [DOI: 10.1177/1076029611432745] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: Evaluation of the effect of using a topical hemostatic agent named “ChitoHem®” on different factors on patients undergoing diagnostic coronary angiography. Methods: The present blind, randomized, controlled study included 124 patients randomly divided into 2 groups. In the treatment group following femoral sheath removal, ChitoHem® powder and in the control group conventional hemostatic procedure was applied. Results: In the treatment group, time to hemostasis, ambulation, and the use of sandbag were significantly shorter compared with the control group, respectively (4.6 ± 1.3 vs 12.4 ± 4.4 minutes, 3.5 ± 2.7 vs 23.0 ± 1.73 hours and 1.6 vs 98.4%; P < .05). There were no significant differences in hematoma formation and re-bleeding between the 2 groups. Conclusion: It was exhibited ChitoHem® topical hemostatic powder used on treatment patients undergoing diagnostic coronary angiography was statistically superior at reducing the time to hemostasis and ambulation as well as the use of sandbags compared with manual compression in control group.
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A cell-type-specific dynamic Bayesian network model for spontaneous and optogenetically evoked activity in the primary visual cortex. BMC Neurosci 2011. [PMCID: PMC3240184 DOI: 10.1186/1471-2202-12-s1-o5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Valsalva-shaped bio-root: an alternative technique for aortic root replacement using a stented bioprosthesis. Thorac Cardiovasc Surg 2010. [DOI: 10.1055/s-0029-1247029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Stabilizing and suicide-peroxide protecting effect of Ni2+ on horseradish peroxidase. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2005. [DOI: 10.1007/bf03245927] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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