| 1. |
- Abrams, M. B., et al.
(författare)
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A Standards Organization for Open and FAIR Neuroscience : the International Neuroinformatics Coordinating Facility
- 2021
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Ingår i: Neuroinformatics. - : Springer Nature. - 1539-2791 .- 1559-0089.
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Tidskriftsartikel (refereegranskat)abstract
- There is great need for coordination around standards and best practices in neuroscience to support efforts to make neuroscience a data-centric discipline. Major brain initiatives launched around the world are poised to generate huge stores of neuroscience data. At the same time, neuroscience, like many domains in biomedicine, is confronting the issues of transparency, rigor, and reproducibility. Widely used, validated standards and best practices are key to addressing the challenges in both big and small data science, as they are essential for integrating diverse data and for developing a robust, effective, and sustainable infrastructure to support open and reproducible neuroscience. However, developing community standards and gaining their adoption is difficult. The current landscape is characterized both by a lack of robust, validated standards and a plethora of overlapping, underdeveloped, untested and underutilized standards and best practices. The International Neuroinformatics Coordinating Facility (INCF), an independent organization dedicated to promoting data sharing through the coordination of infrastructure and standards, has recently implemented a formal procedure for evaluating and endorsing community standards and best practices in support of the FAIR principles. By formally serving as a standards organization dedicated to open and FAIR neuroscience, INCF helps evaluate, promulgate, and coordinate standards and best practices across neuroscience. Here, we provide an overview of the process and discuss how neuroscience can benefit from having a dedicated standards body.
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| 2. |
- Brodin, L, et al.
(författare)
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The reticulospinal glutamate synapse in lamprey: plasticity and presynaptic variability
- 1994
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Ingår i: Journal of Neurophysiology. - 0022-3077 .- 1522-1598. ; 72, s. 592-604
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Tidskriftsartikel (refereegranskat)abstract
- 1. The glutamatergic synapses formed between the unbranched giant reticulospinal axons onto spinal neurons in lamprey offer a central vertebrate synapse in which the presynaptic element can be impaled with one or several microelectrodes, which may be used for recording as well as microinjection of different substances. To provide a basis for the use of this synapse in studies of release mechanisms, we have examined the use-dependent modulation of the synaptic response under conditions of conventional cell body stimulation, and during direct stimulation of the presynaptic axon. 2. To examine the stability of the mixed electrotonic and chemical reticulospinal excitatory postsynaptic potential (EPSP) over time, action potentials were evoked at a rate of 1 Hz for 800-1000 trials. In three out of seven synapses the chemical component remained at a similar amplitude, while in four cases a progressive decrease (up to 35%) occurred. The electrotonic component remained at a similar amplitude in all cases. 3. During paired pulse stimulation of the reticulospinal cell body (pulse interval 65 ms) the chemical EPSP component showed a net facilitation in all cases tested [from 0.64 +/- 0.35 to 0.89 +/- 0.48 (SD) mV, n = 13], while the peak amplitude of the electrotonic component was unchanged (1.37 +/- 0.68 and 1.36 +/- 0.66 mV, respectively). Recording of the axonal action potential during paired pulse stimulation showed that the width of the first and second action potential did not differ [1/2 width (2.48 +/- 0.39 ms and 2.48 +/- 0.42 ms, respectively; n = 8)]. 4. The degree of facilitation varied markedly between different synapses, ranging from an increase of a few percent to a two-fold increase (24 +/- 16% mean change of total EPSP amplitude, corresponding to 44 +/- 26% mean change of chemical EPSP amplitude). This type of variability was also observed in synapses made from the same unbranched reticulospinal axon onto different postsynaptic cells. 5. When paired pulse stimulation was applied to the reticulospinal axon in the very vicinity of the synaptic area (0.1-1 mm) a net depression of the chemical component occurred in 11 out of 19 cases, and in the remaining cases the level of net facilitation was lower as compared with cell body stimulation (range between +17 and -23% change of total EPSP amplitude; mean -5%; n = 19). 6. To test if the change of the EPSP plasticity during local stimulation correlated with an increased transmitter release, two microelectrodes were placed in the same reticulospinal axon at different distances from the synaptic area.(ABSTRACT TRUNCATED AT 400 WORDS)
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| 3. |
- Ericsson, J., et al.
(författare)
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The lamprey provides a vertebrate blueprint of the mammalian basal ganglia
- 2010
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Konferensbidrag (refereegranskat)abstract
- The basal ganglia are a group of subcortical nuclei that play a prominent role in motor function in mammals as well as in lamprey. The aim of the present study was to characterize the different components of the lamprey basal ganglia, and determine to what extent they correspond to those found in the mammalian basal ganglia. Anatomical tract tracing, immunohistochemistry and acute brain slice patch clamp recordings were employed to address this question.Two pallidal regions were identified in the lamprey; one region, considered homologous to the mammalian globus pallidus, was located ventral to the ementia thalami on the telencephalic/diencephalic border. It receives striatal input from inwardly rectifying neurons (IRNs) and contains GABAergic projection neurons, of which those projecting to the tectum were shown to be tonically active. It also contains neurons immunoreactive for parvalbumin. Separate subpopulations of pallidal neurons project to the optic tectum, the diencephalic and mesencephalic locomotor regions (MLR).Another region, in the midbrain, considered homologous to the substantia nigra pars reticulata receives input from a different subset of IRNs and sends GABAergic projections to the tectum and the diencephalic locomotor region. This midbrain region also contains parvalbumin immunoreactive neurons. The main population of striatal neurons, IRNs, displays the anatomical and electrophysiological hallmarks of mammalian medium spiny neurons, including inward rectification and ramping responses to first spike. It also contains neurons with properties similar to fast-spiking neurons. The striatum receives pallial and thalamic input as well as ascending dopaminergic, serotonergic and histaminergic inputs, similar to that in mammals.Our results suggest that the basic features of the basal ganglia with regard to both structure and function are conserved throughout the vertebrate phylogeny, including striatal/pallidal subdivisions.
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| 4. |
- Klaus, A., et al.
(författare)
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Striatal fast-spiking interneurons : from firing patterns to postsynaptic impact
- 2011
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Ingår i: Frontiers in Systems Neuroscience. - : Frontiers Media SA. - 1662-5137. ; 5:July, s. 57-
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Tidskriftsartikel (refereegranskat)abstract
- In the striatal microcircuit, fast-spiking (FS) interneurons have an important role in mediating inhibition onto neighboring medium spiny (MS) projection neurons. In this study, we combined computational modeling with in vitro and in vivo electrophysiological measurements to investigate FS cells in terms of their discharge properties and their synaptic efficacies onto MS neurons. In vivo firing of striatal FS interneurons is characterized by a high firing variability. It is not known, however, if this variability results from the input that FS cells receive, or if it is promoted by the stuttering spike behavior of these neurons. Both our model and measurements in vitro show that FS neurons that exhibit random stuttering discharge in response to steady depolarization do not show the typical stuttering behavior when they receive fluctuating input. Importantly, our model predicts that electrically coupled FS cells show substantial spike synchronization only when they are in the stuttering regime. Therefore, together with the lack of synchronized firing of striatal FS interneurons that has been reported in vivo, these results suggest that neighboring FS neurons are not in the stuttering regime simultaneously and that in vivo FS firing variability is more likely determined by the input fluctuations. Furthermore, the variability in FS firing is translated to variability in the postsynaptic amplitudes in MS neurons due to the strong synaptic depression of the FS-to-MS synapse. Our results support the idea that these synapses operate over a wide range from strongly depressed to almost fully recovered. The strong inhibitory effects that FS cells can impose on their postsynaptic targets, and the fact that the FS-to-MS synapse model showed substantial depression over extended periods of time might indicate the importance of cooperative effects of multiple presynaptic FS interneurons and the precise orchestration of their activity.
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| 5. |
- Ritz, R, et al.
(författare)
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A new software center for the neuroinformatics community
- 2008
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Konferensbidrag (refereegranskat)abstract
- The mission of the International Neuroinformatics Coordinating Facility is to coordinate and foster international activities in neuroinformatics. In general, this includes combining neuroscience and informatics research to develop and apply advanced tools and approaches essential for a major advancement in understanding the structure and function of the brain. There are a significant number of resources available for neuroscientists today, yet they are not used as widely as they should because discovering their existence and evaluating their quality and relevance remain tedious tasks. Furthermore, the development of such resources often relies on isolated laboratories where collaboration across projects would be beneficial. INCF has therefore created a Neuroinformatics Portal, and released a Software Center as its first component.
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| 6. |
- Sweeney, Yann, et al.
(författare)
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A Diffusive Homeostatic Signal Maintains Neural Heterogeneity and Responsiveness in Cortical Networks
- 2015
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Ingår i: PloS Computational Biology. - : Public Library of Science (PLoS). - 1553-734X .- 1553-7358. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Gaseous neurotransmitters such as nitric oxide (NO) provide a unique and often overlooked mechanism for neurons to communicate through diffusion within a network, independent of synaptic connectivity. NO provides homeostatic control of intrinsic excitability. Here we conduct a theoretical investigation of the distinguishing roles of NO-mediated diffusive homeo-stasis in comparison with canonical non-diffusive homeostasis in cortical networks. We find that both forms of homeostasis provide a robust mechanism for maintaining stable activity following perturbations. However, the resulting networks differ, with diffusive homeostasis maintaining substantial heterogeneity in activity levels of individual neurons, a feature disrupted in networks with non-diffusive homeostasis. This results in networks capable of representing input heterogeneity, and linearly responding over a broader range of inputs than those undergoing non-diffusive homeostasis. We further show that these properties are preserved when homeostatic and Hebbian plasticity are combined. These results suggest a mechanism for dynamically maintaining neural heterogeneity, and expose computational advantages of non-local homeostatic processes.
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| 10. |
- Wikström, M, et al.
(författare)
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The action of 5-HT on calcium-dependent potassium channels and on the spinal locomotor network in lamprey is mediated by 5-HT1A-like receptors.
- 1995
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Ingår i: Brain Research. - 0006-8993 .- 1872-6240. ; 678, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- 5-HT has a powerful modulatory action on the firing properties of single neurons as well as on locomotor activity. In lamprey, 5-HT increases the neuronal firing frequency in spinal neurons by reducing the conductance in Ca(2+)-dependent K+ channels (KCa) underlying the slow afterhyperpolarization (sAHP), and it also lowers the burst frequency of the spinal locomotor network. To elucidate which type of 5-HT receptor mediates these effects, different specific receptor agonists and antagonists were applied during intracellular current clamp recordings and during NMDA-induced fictive locomotion in the lamprey spinal cord in vitro preparation. The 5-HT1A receptor agonist 8-OH-DPAT ((+/-)-8-hydroxy-dipropylaminotetralin hydrobromide), the 5-HT1 receptor agonist 5-CT (5-carboxyamidotryptamine maleate) and the 5-HT2 receptor agonist alpha-CH3-5-HT (alpha-methylserotonin maleate) all reproduced the actions of 5-HT at both the cellular and the network levels. The effects of all agonists were completely or partially blocked by the 5-HT1A and 5-HT2 receptor antagonist spiperone (spiroperidol hydrochloride) while selective 5-HT2 receptor antagonists were ineffective. The selective 5-HT1A receptor antagonist S(-)-UH301 (S(-)-5-fluoro-8-hydroxy-dipropylaminotetralin hydrochloride) also counteracted the effect of 5-HT on the sAHP. 5-HT3 and 5-HT4 receptor agonists and antagonists were without effects. The intracellular coupling mechanism was not sensitive to pertussis toxin nor to the cAMP dependent protein kinase blocker (Rp)-cAMPS.(ABSTRACT TRUNCATED AT 250 WORDS)
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