Littérature scientifique sur le sujet « Striatum Dynamics »
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Articles de revues sur le sujet "Striatum Dynamics"
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Bakhurin, Konstantin I., Victor Mac, Peyman Golshani et Sotiris C. Masmanidis. « Temporal correlations among functionally specialized striatal neural ensembles in reward-conditioned mice ». Journal of Neurophysiology 115, no 3 (1 mars 2016) : 1521–32. http://dx.doi.org/10.1152/jn.01037.2015.
Texte intégralRésumé :
As the major input to the basal ganglia, the striatum is innervated by a wide range of other areas. Overlapping input from these regions is speculated to influence temporal correlations among striatal ensembles. However, the network dynamics among behaviorally related neural populations in the striatum has not been extensively studied. We used large-scale neural recordings to monitor activity from striatal ensembles in mice undergoing Pavlovian reward conditioning. A subpopulation of putative medium spiny projection neurons (MSNs) was found to discriminate between cues that predicted the delivery of a reward and cues that predicted no specific outcome. These cells were preferentially located in lateral subregions of the striatum. Discriminating MSNs were more spontaneously active and more correlated than their nondiscriminating counterparts. Furthermore, discriminating fast spiking interneurons (FSIs) represented a highly prevalent group in the recordings, which formed a strongly correlated network with discriminating MSNs. Spike time cross-correlation analysis showed the existence of synchronized activity among FSIs and feedforward inhibitory modulation of MSN spiking by FSIs. These findings suggest that populations of functionally specialized (cue-discriminating) striatal neurons have distinct network dynamics that sets them apart from nondiscriminating cells, potentially to facilitate accurate behavioral responding during associative reward learning.
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Evans, R. C., G. A. Herin, S. L. Hawes et K. T. Blackwell. « Calcium-dependent inactivation of calcium channels in the medial striatum increases at eye opening ». Journal of Neurophysiology 113, no 7 (avril 2015) : 2979–86. http://dx.doi.org/10.1152/jn.00818.2014.
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Influx of calcium through voltage-gated calcium channels (VGCCs) is essential for striatal function and plasticity. VGCCs expressed in striatal neurons have varying kinetics, voltage dependences, and densities resulting in heterogeneous subcellular calcium dynamics. One factor that determines the calcium dynamics in striatal medium spiny neurons is inactivation of VGCCs. Aside from voltage-dependent inactivation, VGCCs undergo calcium-dependent inactivation (CDI): inactivating in response to an influx of calcium. CDI is a negative feedback control mechanism; however, its contribution to striatal neuron function is unknown. Furthermore, although the density of VGCC expression changes with development, it is unclear whether CDI changes with development. Because calcium influx through L-type calcium channels is required for striatal synaptic depression, a change in CDI could contribute to age-dependent changes in striatal synaptic plasticity. Here we use whole cell voltage clamp to characterize CDI over developmental stages and across striatal regions. We find that CDI increases at the age of eye opening in the medial striatum but not the lateral striatum. The developmental increase in CDI mostly involves L-type channels, although calcium influx through non-L-type channels contributes to the CDI in both age groups. Agents that enhance protein kinase A (PKA) phosphorylation of calcium channels reduce the magnitude of CDI after eye opening, suggesting that the developmental increase in CDI may be related to a reduction in the phosphorylation state of the L-type calcium channel. These results are the first to show that modifications in striatal neuron properties correlate with changes to sensory input.
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Kondabolu, Krishnakanth, Erik A. Roberts, Mark Bucklin, Michelle M. McCarthy, Nancy Kopell et Xue Han. « Striatal cholinergic interneurons generate beta and gamma oscillations in the corticostriatal circuit and produce motor deficits ». Proceedings of the National Academy of Sciences 113, no 22 (16 mai 2016) : E3159—E3168. http://dx.doi.org/10.1073/pnas.1605658113.
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Cortico-basal ganglia-thalamic (CBT) neural circuits are critical modulators of cognitive and motor function. When compromised, these circuits contribute to neurological and psychiatric disorders, such as Parkinson’s disease (PD). In PD, motor deficits correlate with the emergence of exaggerated beta frequency (15–30 Hz) oscillations throughout the CBT network. However, little is known about how specific cell types within individual CBT brain regions support the generation, propagation, and interaction of oscillatory dynamics throughout the CBT circuit or how specific oscillatory dynamics are related to motor function. Here, we investigated the role of striatal cholinergic interneurons (SChIs) in generating beta and gamma oscillations in cortical-striatal circuits and in influencing movement behavior. We found that selective stimulation of SChIs via optogenetics in normal mice robustly and reversibly amplified beta and gamma oscillations that are supported by distinct mechanisms within striatal-cortical circuits. Whereas beta oscillations are supported robustly in the striatum and all layers of primary motor cortex (M1) through a muscarinic-receptor mediated mechanism, gamma oscillations are largely restricted to the striatum and the deeper layers of M1. Finally, SChI activation led to parkinsonian-like motor deficits in otherwise normal mice. These results highlight the important role of striatal cholinergic interneurons in supporting oscillations in the CBT network that are closely related to movement and parkinsonian motor symptoms.
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Carrillo-Reid, Luis, Fatuel Tecuapetla, Nicolas Vautrelle, Adán Hernández, Ramiro Vergara, Elvira Galarraga et José Bargas. « Muscarinic Enhancement of Persistent Sodium Current Synchronizes Striatal Medium Spiny Neurons ». Journal of Neurophysiology 102, no 2 (août 2009) : 682–90. http://dx.doi.org/10.1152/jn.00134.2009.
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Network dynamics denoted by synchronous firing of neuronal pools rely on synaptic interactions and intrinsic properties. In striatal medium spiny neurons, N-methyl-d-aspartate (NMDA) receptor activation endows neurons with nonlinear capabilities by inducing a negative-slope conductance region (NSCR) in the current–voltage relationship. Nonlinearities underlie associative learning, procedural memory, and the sequential organization of behavior in basal ganglia nuclei. The cholinergic system modulates the function of medium spiny projection neurons through the activation of muscarinic receptors, increasing the NMDA-induced NSCR. This enhancement is reflected as a change in the NMDA-induced network dynamics, making it more synchronous. Nevertheless, little is known about the contribution of intrinsic properties that promote this activity. To investigate the mechanisms underlying the cholinergic modulation of bistable behavior in the striatum, we used whole cell and calcium-imaging techniques. A persistent sodium current modulated by muscarinic receptor activation participated in the enhancement of the NSCR and the increased network synchrony. These experiments provide evidence that persistent sodium current generates bistable behavior in striatal neurons and contributes to the regulation of synchronous network activity. The neuromodulation of bistable properties could represent a cellular and network mechanism for cholinergic actions in the striatum.
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Ding, Long. « Distinct dynamics of ramping activity in the frontal cortex and caudate nucleus in monkeys ». Journal of Neurophysiology 114, no 3 (septembre 2015) : 1850–61. http://dx.doi.org/10.1152/jn.00395.2015.
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The prefronto-striatal network is involved in many cognitive functions, including perceptual decision making and reward-modulated behaviors. For well-trained subjects, neural responses frequently show similar patterns in the prefrontal cortex and striatum, making it difficult to tease apart distinct regional contributions. Here I show that, despite similar mean firing rate patterns, prefrontal and striatal responses differ in other temporal dynamics for both perceptual and reward-based tasks. Compared with simulation results, the temporal dynamics of prefrontal activity are consistent with an accumulation of sensory evidence used to solve a perceptual task but not with an accumulation of reward context-related information used for the development of a reward bias. In contrast, the dynamics of striatal activity is consistent with an accumulation of reward context-related information and with an accumulation of sensory evidence during early stimulus viewing. These results suggest that prefrontal and striatal neurons may have specialized functions for different tasks even with similar average activity.
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Kudryavtseva, V. A., A. V. Moiseeva, S. G. Mukhamedova, G. A. Piavchenko et S. L. Kuznetsov. « Age- and sex-related dynamics of structural and functional motor behavior interactions in striatum neurons in rats ». Sechenov Medical Journal 13, no 2 (7 décembre 2022) : 20–29. http://dx.doi.org/10.47093/2218-7332.2022.13.2.20-29.
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Aim. To study the age-related dynamics of structural and functional interactions of striatal neurons in the implementation of acts of motor behaviour in rats of both sexes.Materials and methods. The study was carried out on 36 Wistar rats of both sexes aged 2, 7 and 16 months (n = 6 per group). In animals of all groups, locomotor activity was determined using a Laboras device (Metris, the Netherlands) for15 minutes, after which the brain was sampled to determine the number and size of neurons in the striatum. The median and interquartile range of the index of motor activity and the number of neurons were determined, and to study the relationship between these indicators, a correlation and regression analysis was performed with the construction of linear and polynomial trends, and the coefficient of determination R2 was calculated.Results. The size of neurons did not change significantly with age in the rats of both sexes. The number of neurons differed statistically in the rats of different sexes in all age groups. In male rats, the maximum number of neurons was noted at the age of 7 months with a decrease to 16 months. In female rats, the maximum number of neurons was recorded at the age of 2 months with a further decrease to 7 and 16 months. According to the regression analysis, a linear strong relationship (R2 =0.80 for males, R2 = 0.79 for females) was established between the number of neurons in the striatum and motor activity in 2-month-old animals. At the age of 7 and 16 months the relationship is non-linear.Conclusion. The number of neurons in the striatum is subject to sex and age dynamics, while their size remains unchanged from 2 to 16 months. For animals of both sexes, a decrease in the role of the striatum in providing motor activity in the process of growing up was noted. This relationship reaches its maximum in 2-month-old rats and then decreases.
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Zhang, Rui L., Michael Chopp, Sara R. Gregg, Yier Toh, Cindi Roberts, Yvonne LeTourneau, Benjamin Buller, Longfei Jia, Siamak P. Nejad Davarani et Zheng G. Zhang. « Patterns and Dynamics of Subventricular Zone Neuroblast Migration in the Ischemic Striatum of the Adult Mouse ». Journal of Cerebral Blood Flow & ; Metabolism 29, no 7 (13 mai 2009) : 1240–50. http://dx.doi.org/10.1038/jcbfm.2009.55.
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The migratory behavior of neuroblasts after a stroke is poorly understood. Using time-lapse microscopy, we imaged migration of neuroblasts and cerebral vessels in living brain slices of adult doublecortin (DCX, a marker of neuroblasts) enhanced green fluorescent protein (eGFP) transgenic mice that were subjected to 7 days of stroke. Our results show that neuroblasts originating in the subventricular zone (SVZ) of adult mouse brain laterally migrated in chains or individually to reach the ischemic striatum. The chains were initially formed at the border between the SVZ and the striatum by neuroblasts in the SVZ and then extended to the striatum. The average speed of DCX-eGFP-expressing cells within chains was 28.67 ± 1.04 μm/h, which was significantly faster ( P < 0.01) than the speed of the cells in the SVZ (17.98 ± 0.57 μm/h). Within the ischemic striatum, individual neuroblasts actively extended or retracted their processes, suggestive of probing the immediate microenvironment. The neuroblasts close to cerebral blood vessels exhibited multiple processes. Our data suggest that neuroblasts actively interact with the microenvironment to reach the ischemic striatum by multiple migratory routes.
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Chepkova, Aisa N., Susanne Schönfeld et Olga A. Sergeeva. « Age-Related Alterations in the Expression of Genes and Synaptic Plasticity Associated with Nitric Oxide Signaling in the Mouse Dorsal Striatum ». Neural Plasticity 2015 (2015) : 1–14. http://dx.doi.org/10.1155/2015/458123.
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Age-related alterations in the expression of genes and corticostriatal synaptic plasticity were studied in the dorsal striatum of mice of four age groups from young (2-3 months old) to old (18–24 months of age) animals. A significant decrease in transcripts encoding neuronal nitric oxide (NO) synthase and receptors involved in its activation (NR1 subunit of the glutamate NMDA receptor and D1 dopamine receptor) was found in the striatum of old mice using gene array and real-time RT-PCR analysis. The old striatum showed also a significantly higher number of GFAP-expressing astrocytes and an increased expression of astroglial, inflammatory, and oxidative stress markers. Field potential recordings from striatal slices revealed age-related alterations in the magnitude and dynamics of electrically induced long-term depression (LTD) and significant enhancement of electrically induced long-term potentiation in the middle-aged striatum (6-7 and 12-13 months of age). Corticostriatal NO-dependent LTD induced by pharmacological activation of group I metabotropic glutamate receptors underwent significant reduction with aging and could be restored by inhibition of cGMP hydrolysis indicating that its age-related deficit is caused by an altered NO-cGMP signaling cascade. It is suggested that age-related alterations in corticostriatal synaptic plasticity may result from functional alterations in receptor-activated signaling cascades associated with increasing neuroinflammation and a prooxidant state.
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Gangarossa, Giuseppe, Sylvie Perez, Yulia Dembitskaya, Ilya Prokin, Hugues Berry et Laurent Venance. « BDNF Controls Bidirectional Endocannabinoid Plasticity at Corticostriatal Synapses ». Cerebral Cortex 30, no 1 (25 avril 2019) : 197–214. http://dx.doi.org/10.1093/cercor/bhz081.
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AbstractThe dorsal striatum exhibits bidirectional corticostriatal synaptic plasticity, NMDAR and endocannabinoids (eCB) mediated, necessary for the encoding of procedural learning. Therefore, characterizing factors controlling corticostriatal plasticity is of crucial importance. Brain-derived neurotrophic factor (BDNF) and its receptor, the tropomyosine receptor kinase-B (TrkB), shape striatal functions, and their dysfunction deeply affects basal ganglia. BDNF/TrkB signaling controls NMDAR plasticity in various brain structures including the striatum. However, despite cross-talk between BDNF and eCBs, the role of BDNF in eCB plasticity remains unknown. Here, we show that BDNF/TrkB signaling promotes eCB-plasticity (LTD and LTP) induced by rate-based (low-frequency stimulation) or spike-timing–based (spike-timing–dependent plasticity, STDP) paradigm in striatum. We show that TrkB activation is required for the expression and the scaling of both eCB-LTD and eCB-LTP. Using 2-photon imaging of dendritic spines combined with patch-clamp recordings, we show that TrkB activation prolongs intracellular calcium transients, thus increasing eCB synthesis and release. We provide a mathematical model for the dynamics of the signaling pathways involved in corticostriatal plasticity. Finally, we show that TrkB activation enlarges the domain of expression of eCB-STDP. Our results reveal a novel role for BDNF/TrkB signaling in governing eCB-plasticity expression in striatum and thus the engram of procedural learning.
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Bigan, Erwan, Satish Sasidharan Nair, François-Xavier Lejeune, Hélissande Fragnaud, Frédéric Parmentier, Lucile Mégret, Marc Verny, Jeff Aaronson, Jim Rosinski et Christian Neri. « Genetic cooperativity in multi-layer networks implicates cell survival and senescence in the striatum of Huntington’s disease mice synchronous to symptoms ». Bioinformatics 36, no 1 (22 juin 2019) : 186–96. http://dx.doi.org/10.1093/bioinformatics/btz514.
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Abstract Motivation Huntington’s disease (HD) may evolve through gene deregulation. However, the impact of gene deregulation on the dynamics of genetic cooperativity in HD remains poorly understood. Here, we built a multi-layer network model of temporal dynamics of genetic cooperativity in the brain of HD knock-in mice (allelic series of Hdh mice). To enhance biological precision and gene prioritization, we integrated three complementary families of source networks, all inferred from the same RNA-seq time series data in Hdh mice, into weighted-edge networks where an edge recapitulates path-length variation across source-networks and age-points. Results Weighted edge networks identify two consecutive waves of tight genetic cooperativity enriched in deregulated genes (critical phases), pre-symptomatically in the cortex, implicating neurotransmission, and symptomatically in the striatum, implicating cell survival (e.g. Hipk4) intertwined with cell proliferation (e.g. Scn4b) and cellular senescence (e.g. Cdkn2a products) responses. Top striatal weighted edges are enriched in modulators of defective behavior in invertebrate models of HD pathogenesis, validating their relevance to neuronal dysfunction in vivo. Collectively, these findings reveal highly dynamic temporal features of genetic cooperativity in the brain of Hdh mice where a 2-step logic highlights the importance of cellular maintenance and senescence in the striatum of symptomatic mice, providing highly prioritized targets. Availability and implementation Weighted edge network analysis (WENA) data and source codes for performing spectral decomposition of the signal (SDS) and WENA analysis, both written using Python, are available at http://www.broca.inserm.fr/HD-WENA/. Supplementary information Supplementary data are available at Bioinformatics online.
Thèses sur le sujet "Striatum Dynamics"
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Badreddine, Nagham. « Caractérisation des substrats neuronaux de la mémoire procédurale : rôle de la dynamique des réseaux corticostriataux Spatiotemporal reorganization of corticostriatal network 1 dynamics encodes 2 motor skill learning ». Thesis, Université Grenoble Alpes, 2020. https://thares.univ-grenoble-alpes.fr/2020GRALV032.pdf.
Texte intégralRésumé :
La mémoire procédurale est la mémoire des habitudes motrices. Les ganglions de la base (GB), un groupe de structures impliqué dans les fonctions motrices et cognitives, sont responsables de la formation de cette mémoire. Le striatum, principale structure d’entrée des GB, joue un rôle central dans le transfert de l’information entre le cortex et les autres structures sous-corticales, assurant ainsi la sélection et l’intégration de l’information corticale au sein de boucles fonctionnelles parallèles. Lors d’un apprentissage procédural, le comportement est tout d’abord dirigé vers un but, impliquant les boucles associatives et le striatum dorsomédial (DMS), pour ensuite évoluer vers un comportement habituel automatique, impliquant les boucles sensorimotrices et le striatum dorsolatéral (DLS). L’anatomie des circuits et la dynamique des réseaux striataux au cours de l’apprentissage procédural ont été bien décrites. Cependant, comment la mémoire procédurale est précisément encodée au niveau des réseaux corticostriataux (CS) reste inconnu.Dans mon travail de thèse, nous nous sommes intéressés à la caractérisation des dynamiques des réseaux CS impliqués dans l’apprentissage procédural et nous avons exploré l’existence de substrats neuronaux responsables de la formation de cette mémoire. Grâce à l’imagerie calcique ex vivo nous avons monitoré l’activité des réseaux CS durant les différentes phases d’apprentissage. Nous avons extrait et analysé les signaux calciques des neurones épineux moyens (MSN), les neurones de sortie du striatum. Afin de distinguer les MSNs des autres neurones striataux, nous avons développé un classifieur basé sur les réponses calciques des neurones et leur morphologie. Nous avons montré qu’il existe une réorganisation spécifique des réseaux DMS pendant la 1ère phase d’apprentissage moteur. L’activité dans le DMS est diminuée après un entraînement léger, avec une forte activité (HA) maintenue dans un petit groupe de cellules, et retournant à un niveau basal après un entrainement intense. Dans le DLS, la réorganisation est graduelle et localisée dans des ‘clusters’ d’activité (HA) après un entrainement intense. L’existence des cellules et clusters HA est directement corrélée à la qualité de l’apprentissage. Nous avons ensuite exploré les mécanismes sous-tendant cette réorganisation. Grâce à des enregistrements en patch-clamp nous avons examiné les propriétés des cellules et clusters HA et montré une augmentation du poids synaptique des afférences du cortex cingulaire sur les cellules HA dans le DMS après un entrainement léger. Des études de traçage anatomique ont montré des changements plus robustes dans le DLS avec une augmentation du nombre de projections du cortex somatosensoriel après entrainement intense. Une stratégie cFos-TRAP couplée à la chimiogénétique nous a permis d’inhiber spécifiquement les cellules et clusters HA, et montrer que cela affecte l’apprentissage moteur. Ceci montre la nécessité de ces cellules dans les premières et dernières phases de l’apprentissage moteur respectivement.Ensuite, notre but était d’explorer s’il existe des déficits d’apprentissage moteur dans une phase présymptomatique dans un modèle murin de la maladie de Huntington, et d’examiner l’association de ces déficits à des altérations au niveau des réseaux CS. Nous avons d’abord montré qu’il existait des déficits dans la dernière phase d’apprentissage dans ce modèle murin. Grâce à l’imagerie calcique ex vivo, nous avons observé une altération des réseaux du DMS et du DLS dans des conditions naïve ainsi qu’une absence de réorganisation des réseaux après l’apprentissage. Ainsi, ces résultats confirment l’importance de la réorganisation des réseaux pour l’apprentissage moteur.L’ensemble de ce travail offre de nouvelles perspectives quant au rôle des réseaux CS et leur réorganisation dans l’apprentissage moteur. La nécessité des cellules HA et des clusters ouvrent les portes du monde de l’engramme dans les réseaux striatauxProcedural memory is the memory of habits, involved in the acquisition and maintenance of new motor skills. The neural substrates underlying this memory are the basal ganglia (BG), a group of structures involved in motor and cognitive functions. The input nucleus of the BG is the striatum, earning it a central role in relaying information between the cortex and other subcortical structures, thus ensuring the selection and integration of cortical information within parallel functional loops. Procedural learning first follows a goal-directed behavior mediated by the associative loops, including the dorsomedial striatum (DMS), which is then transferred to an automatic behavior where habit is formed and mediated by the sensorimotor loops including the dorsolateral striatum (DLS). The anatomy and the evolution of the dynamics of the striatal networks has been well described during procedural learning, and the involvement of each striatal territory in a specific phase of learning established. However, how procedural learning is encoded at the level of the corticostriatal networks remains unknown.During my PhD work, we were interested in characterizing the dynamics of the corticostriatal networks involved in motor skill learning and determining the neural correlates responsible for the formation of this memory. We first used two-photon ex vivo calcium imaging to monitor the activity of the networks during the different phases of procedural learning. First we extracted the calcium responses of only medium spiny neurons (MSNs), the striatal output neurons. To distinguish MSNs from other striatal neurons, we developed a cell-sorting classifier based on the calcium responses of neurons and their morphology. We showed a specific reorganization of the DMS networks during the early phase, and the DLS during the late phase of motor skill learning. In DMS, the activity of the networks decreased after early training and returned to a basal level after late training. The main activity of the DMS networks was held by a group of highly active (HA) cells. In DLS, the reorganization of the activity was gradual and localized in small clusters of activity after late training. We then examined the properties of the HA cells in DMS and clusters in DLS. The existence of HA cells and clusters are directly correlated to the performance of the animals. Whole-cell patch-clamp recordings allowed us to characterize electrophysiological properties of HA bells and determine an increase of the synaptic weight of cingulate cortex inputs to HA cells in DMS after early learning. Anatomical tracing showed more robust changes in the DLS with an increase of the number of somatosensory projections to the DLS after late training. Using an AAV cFos-TRAP strategy coupled to chemogenetics, we inhibited HA and cluster cells, leading to impaired motor learning. These experiments thus highlighted the necessity of these cells in early and late phases of motor skill learning respectively.Next we wanted to explore if deficits in motor skill learning occur in a premotor-symptomatic phase of a mouse model of Huntington’s disease (HD), and if they would be associated to dysfunctions in the corticostriatal networks. We first showed deficits in the late phase of motor skill learning in a mouse model of HD. Using ex vivo two-photon calcium imaging, we explored the DMS and DLS networks and we observed an alteration of both networks in naïve HD animals and in addition, an absence of reorganization upon motor skill learning. These results confirm the importance of the reorganization of the networks in motor skill learning.Altogether, this work provides a new insight on the role of the corticostriatal networks and their reorganization in motor skill learning. The necessity of HA and cluster cells opens the door of the ‘engram’ world to the striatal networks
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Rutherford, Erin Cathleen. « MICROELECTRODE ARRAY RECORDINGS OF L-GLUTAMATE DYNAMICS IN THE BRAINS OF FREELY MOVING RATS ». UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/523.
Texte intégralRésumé :
L-glutamate (Glu) is the predominant excitatory neurotransmitter inthe mammalian central nervous system (CNS) and is associated with a widevariety of functions including motor behavior and sensory perception. Whilemicrodialysis methods have been used to record tonic levels of Glu, little isknown about the more rapid changes in Glu signals that may occur in awakeanimals. We have previously reported acute recording methods using anenzyme-based microelectrode array (MEA) with fast temporal resolution (800msec), that is minimally invasive and is capable of detecting low levels of Glu (andlt;0.2 ??M) in anesthetized animals with little interference from other analytes. Wehave made a series of modifications to the MEA design to allow for reliablemeasures in the brain of awake behaving rats. In these studies, wecharacterized the effects of chronic implantation of the MEA into the striatum andprefrontal cortex (PFC) of Fischer 344 and Long Evans rats. We measuredresting levels of Glu and local application of Glu for 7 days without a significantloss of sensitivity and determined that Glu measures due to exogenous Gluvaried between rat strain and brain region. In addition, we determined theviability of the recordings in the brains of awake animals. We performed studiesof tail-pinch induced stress which caused an increase in Glu in the striatum andPFC of Long Evans and Fischer 344 rats. Histological data show that chronicimplantation of our MEAs caused minimal injury to the CNS. Taken together, ourdata support that chronic recordings of tonic and phasic Glu can be carried out inawake rats reliably for 7 days in vivo allowing for longer term studies of Gluregulation in behaving rats.
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Howe, Mark W. (Mark William). « Dynamics of dopamine signaling and network activity in the striatum during learning and motivated pursuit of goals ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79186.
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Thesis (Ph. D. in Neuroscience)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 2013.Cataloged from PDF version of thesis. "February 2013."
Includes bibliographical references (p. 118-126).
Learning to direct behaviors towards goals is a central function of all vertebrate nervous systems. Initial learning often involves an exploratory phase, in which actions are flexible and highly variable. With repeated successful experience, behaviors may be guided by cues in the environment that reliably predict the desired outcome, and eventually behaviors can be executed as crystallized action sequences, or "habits", which are relatively inflexible. Parallel circuits through the basal ganglia and their inputs from midbrain dopamine neurons are believed to make critical contributions to these phases of learning and behavioral execution. To explore the neural mechanisms underlying goal-directed learning and behavior, I have employed electrophysiological and electrochemical techniques to measure neural activity and dopamine release in networks of the striatum, the principle input nucleus of the basal ganglia as rats learned to pursue rewards in mazes. The electrophysiological recordings revealed training dependent dynamics in striatum local field potentials and coordinated neural firing that may differentially support both network rigidity and flexibility during pursuit of goals. Electrochemical measurements of real-time dopamine signaling during maze running revealed prolonged signaling changes that may contribute to motivating or guiding behavior. Pathological over or under-expression of these network states may contribute to symptoms experienced in a range of basal ganglia disorders, from Parkinson's disease to drug addiction.
by Mark W. Howe.
Ph.D.in Neuroscience
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Nickell, Justin Robert. « AGE-RELATED ALTERATIONS IN THE DYNAMICS OF L-GLUTAMATE REGULATION IN THE STRIATUM OF THE FISCHER 344 RAT ». UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/236.
Texte intégralRésumé :
L-glutamate is the predominant excitatory amino acid neurotransmitter inthe mammalian central nervous system. Prior aging studies have focusedprimarily on dopaminergic circuitry of the striatum, and data obtained studyingglutamate regulation in the striatum have been largely equivocal. Thesediscrepancies are due in large part to the limitations of microdialysis; while it isextremely sensitive to minute concentrations of analyte, it is lacking in terms ofthe temporal resolution necessary to study a neurotransmitter with rapid releaseand clearance kinetics such as glutamate. In order to address this matter, ourlaboratory has designed a ceramic-based multisite microelectrode with thecapability to detect and analyze fluctuations in extracellular glutamateconcentrations on a sub-second basis. These microelectrodes were utilized tostudy the phasic release and uptake dynamics of potassium-evoked glutamate inthe striatum of young (6 month), late-middle aged (18 month) and aged (24month) Fischer 344 rats. Our results showed a reduced glutamate clearancerate and an attenuated response to potassium depolarization in the corticostriatalprojections of aged animals in comparison to other age groups. In addition,average maximal glutamate release amplitudes were decreased in the striatumof aged animals. Pressure ejection of exogenous glutamate solution furtherconfirmed the decreased glutamate clearance ability of the aged striatum. Thesepotassium and exogenous glutamate data also highlighted a markeddorsoventral gradient in the striatum in terms of glutamate release and clearanceability. We further explored this phenomenon of age-related decreased glutamateuptake by coupling our in vivo technology with classical immunoblotting andbiotinylation techniques in order to investigate glutamate transporter regulation.Decreased glutamate clearance in the aged rats cannot be attributed to areduction in steady-state total transporter protein levels. Rather, our resultsindicate that reduced plasma membrane surface trafficking of GLAST in the agedstriatum may be partially responsible for this effect. Finally, we modified ourmicroelectrodes to study basal glutamate levels in the striatum of the aging,freely moving rat. This approach allowed us to study extracellular glutamateregulation free from the potential confounding variable of anesthesia. Our resultsdemonstrate that there is no significant alteration in basal glutamate levels inaging in the brain regions investigated. More importantly, this study validated theefficacy of the utilization of ceramic-based multisite microelectrodes for the studyof alterations in glutamate neurotransmission in the aging, freely moving rat, andit lays the foundation for future work correlating such changes with age associatedimpairments in motor function.
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Omar, Muhammad Yusof. « Modulation of Presynaptic Dopamine Synthesis and Storage Dynamics by D2-Like Receptor Partial Agonist Antipsychotics in Rat Brain Striatum ». Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670700.
Texte intégralRésumé :
La regulació dopaminèrgica presinàptica és important per mantenir un equilibri homeostàtic dels nivells emmagatzemats de dopamina i el seu alliberament. Els canvis en la neurotransmissió de dopamina contribueixen a trastorns neurològics i psiquiàtrics. Treballs recents del nostre grup (Ma et al., 2015; González-Sepúlveda et al.,-presentada) van descriure importants efectes de diverses classes de fàrmacs dopaminèrgics sobre la síntesi de dopamina, inclosa la L-DOPA (emprada en Parkinson), la tetrabenazina (Huntington) i aripiprazol (esquizofrènia). En aquest estudi, vam confirmar i ampliar aquestes troballes i vam comparar els efectes dels antipsicòtics agonistes parcials D2R cariprazina i brexpiprazol, els pricostimulants amfetamina i metilfenidat i diversos altres compostos selectius i experimentals. L’estriat cerebral de rata va ser trocejat i incubat ex-vivo en presència o absència d’aquests fàrmacs a diferents concentracions. De manera espontània, la dopamina i la serotonina es van acumular al llarg del temps i van assolir nivells d’emmagatzematge gairebé màxims. Aquest enfocament experimental ens va permetre avaluar la seva síntesi i dinàmica d’emmagatzematge sota la influència d’agents farmacològics escollits. Els nostres resultats podrien ser útils per comprendre els mecanismes d’acció dels antipsicòtics, i podrien facilitar més investigacions amb models animals i assajos clínics mitjançant nous agents dopaminèrgics.La regulación dopaminérgica presináptica es importante para mantener un equilibrio homeostático de los niveles almacenados y liberación de dopamina. Los cambios en la neurotransmisión de dopamina contribuyen a los trastornos neurológicos y psiquiátricos. Hallazgos recientes de nuestro grupo (Ma et al., 2015; González-Sepúlveda et al., presentado) describieron los fuertes efectos de varias clases de medicamentos dopaminérgicos en la síntesis de dopamina, incluida L-DOPA (utilizada en Parkinson), tetrabenazina (Huntington) y aripiprazol (esquizofrenia). En este estudio, confirmamos y ampliamos esos hallazgos y comparamos los efectos de los antipsicóticos agonistas parciales D2R cariprazina y brexpiprazol, las psicoestimulantes anfetamina y metilfenidato varios otros compuestos selectivos y experimentales. El estriado cerebral de rata fue troceado e incubado ex-vivo en presencia o ausencia de estos fármacos a diferentes concentraciones. Espontáneamente, la dopamina y la serotonina se acumularon con el tiempo alcanzando niveles de almacenamiento casi máximos. Este enfoque experimental nos permitió evaluar su dinámica de síntesis y almacenamiento bajo la influencia de los agentes farmacológicos elegidos. Nuestros resultados podrían ser útiles para comprender los mecanismos de acción de los antipsicóticos, y podrían facilitar la investigación futura con modelos animales y ensayos clínicos utilizando nuevos agentes dopaminérgicos.
Presynaptic dopaminergic regulation is important to maintain a homeostatic balance of dopamine stored levels and release. Changes in dopamine neurotransmission contribute to neurological and psychiatric disorders. Recent findings from our group (Ma et al., 2015; González-Sepúlveda et al.,-submitted) describe strong effects of several classes of dopaminergic drugs on dopamine synthesis, including L-DOPA (used in Parkinson), tetrabenazine (Huntington) and aripiprazole (schizophrenia). In this study, I confirm and extend those findings and compare the effects of D2R partial agonist antipsychotics cariprazine and brexpiprazole, the psychostimulants amphetamine and methylphenidate, and several other selective and experimental compounds. Rat brain striatum was minced and incubated ex-vivo in the presence or absence of these drugs at different concentrations. Spontaneously, dopamine and serotonin accumulated over time reaching near-maximal storage levels. This experimental approach allowed me to evaluate their synthesis and storage dynamics under the influence of chosen pharmacological agents. My results could be useful to understand the mechanisms of action of antipsychotics, and they could facilitate further research with animal models and clinical trials using new dopaminergic agents.
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Gritti, M. « ROLE OF EXCITATORY SEROTONERGIC SIGNALING IN THE PATHWAY-SPECIFIC NEUROMODULATION OF STRIATAL SYNAPTIC PLASTICITY ». Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/334490.
Texte intégralRésumé :
The dorsolateral striatum (DLS) of the basal ganglia plays a critical role in action selection and motor control. The DLS receives cortical and thalamic afferents, which are extensively modulated by monoaminergic inputs, such as dopamine and serotonin (5-HT). Dopamine and 5-HT act as circuit neuromodulators by activating both stimulatory (Gs) and inhibitory (Gi) protein-coupled receptors that regulate synaptic mechanisms of plasticity.
On a system level, 5-HT signal has been classically associated with learning of negative events, acting as an opponent of dopamine regulation of rewarding processes. Recent evidence has challenged this view, suggesting that 5HT signaling can synergize with dopamine signaling to shape reward-guided behavior. However, the molecular and synaptic correlates of this behavioral role of 5-HT at striatal circuits remain to be established.
To address this hypothesis, we investigated the role of serotonergic signaling in regulating the strength of glutamatergic synaptic connections to the Medium Spiny Neurons of the direct pathway (dMSNs), which mediate movement, reward and reinforcement. Specifically, we focused on the regulation of distinct forms of long-term synaptic plasticity that depend on both the relative timing of a neuron output and an input spike (Spike timing-dependent plasticity, STDP), and on the pattern of neuronal stimulation (high-frequency stimulation, HFS). Upon a STDP protocol, the chemo-genetic inhibition of 5-HT release resulted in a long lasting depression (STDP-LTD) of glutamatergic afferents to the dMSNs of the DLS. The synaptic effects of chemo-genetic inhibition of 5-HT release were recapitulated by the pharmacological inhibition of the Gs-coupled 5-HT4 receptor subtype (5-HT4R).
This form of LTD was independent from presynaptic CB1 receptor (CB1R) activation, it showed a postsynaptic locus of expression, and it was associated with an increased dendritic Ca2+ signal. We obtained similar results upon HFS; antagonism of 5-HT4R resulted in a CB1R independent form of HFS-LTD, which was associated with enhanced dendritic Ca2+ levels.
Collectively, these data provide molecular and synaptic insights on the neuromodulatory role of 5-HT at striatal circuits. Dysfunctional serotonergic modulation of striatal circuits has been associated with repetitive behaviors in obsessive-compulsive disorders (OCD). Thus, elucidating how 5-HT4R manipulation affects aspects of reward-guided behavior, and how this is causally relevant for defined cognitive processes implicated in action control, could facilitate the development of new pharmacological approaches to treat OCD symptoms.
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Arakaki, Takafumi. « Collective dynamics of basal ganglia-thalamo-cortical loops and their roles in functions and dysfunctions ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066123/document.
Texte intégralRésumé :
Les ganglions de la base (GB) sont principalement connus pour leurs fonctions motrices, mais présentent également des fonctions non motrices. Sans surprise, il a été montré qu’ils sont impliqués dans des troubles moteurs tels que la maladie de Parkinson ou les dystonies. Des études récentes suggèrent que les GB jouent également un rôle prépondérant dans des maladies “non-motrices” telles que l’épilepsie d’absence , qui est une épilepsie généralisée non convulsive. Dans l’ensemble de ces dysfonctions des GB, les symptômes sont accompagnés de différents patrons oscillants d’activité neuronale souvent synchronisés entre les différents noyaux des GB, le cortex et d’autres aires cérébrales. Comment les GB peuvent-ils favoriser ou soutenir ces différentes activitées oscillantes?Des expériences récentes ont montré le rôle clé joué par les GB dans l’épilepsie d’absence et remettent en question le point de vue traditionnel selon lequel les circuits thalamo-corticaux sont responsables des crises d’absence. Nous proposons une nouvelle théorie selon laquelle les rétroactions opérées par les GB sur l’activité corticale rend le réseau bistable et entraîne les patrons d’activité oscillante qui apparaîssent pendant les crises. Notre théorie est compatible avec l’ensemble des résultats expérimentaux connus et elle prédit qu’un input excitateur transitoire sur le cortex peut terminer prématurément les crises d’absence. Nous présentons ici des résultats préliminaires en accord avec cette prédiction.De multiples fréquences des oscillations d’activité sont observées dans la maladie de Parkinson au sein des GB, telles que les fréquences correspondant aux tremblement des membres ou encore les oscillations béta. Nous montrons que notre model peut générer des oscillations à différentes échelles temporelles qui coïncident avec les fréquences des oscillations dans la maladie de Parkinson. Notre théorie peut rendre compte des oscillations observées dans la maladie de Parkinson et dans l’epilépsie d’absence dans un cadre théorique unifié et suggère deux scénarios pour expliquer les multiples fréquences des oscillations d’activité, à la fois pathologiques et fonctionnellesThe Basal Ganglia (BG) are thought to be involved primarily in motor but also in non-motor functions. Unsurprisingly, the BG are shown to be involved in motor dysfunctions such as Parkinson's disease or dystonia. More recent studies suggest the key role of the BG in "non-motor" diseases such as absence epilepsy which is a generalized non-convulsive epilepsy. In these diseases, symptoms accompany various oscillatory patterns of neural activity often synchronized across the BG, cortex and other brain areas. How can the BG support these different kinds of oscillatory patterns?Recent experiments have highlighted the key role of the BG in absence seizures and question the traditional view in which thalamocortical circuits underlie absence seizures. We propose a novel theory according to which the feedbacks of cortical activity through BG make this network bistable and drive the oscillatory patterns of activity occurring during the seizures. Our theory is compatible with virtually all known experimental results and it predicts that well-timed transient excitatory inputs to the cortex advance the termination of absence seizures. We report preliminary experimental results consistent with this prediction.Multiple oscillatory frequencies are observed in Parkinsonian BG such as the frequencies of the limb tremor and the beta oscillations. We show that our model can generate oscillations with multiple timescales which resemble Parkinsonian oscillations. Our theory can model the oscillations in Parkinson's disease and absence epilepsy in a unified framework and points to two scenarios to explain multiple frequencies of pathological and functional oscillations
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Huo, Jiuzhou. « Regulation of Mitochondrial Calcium Dynamics in Striated Muscle Function ». University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595846761184679.
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Bercovici, Debra Ann. « Optogenetic dissection of temporal dynamics of amygdala-striatal interplay during risk/reward decision making ». Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62749.
Texte intégralRésumé :
Assessing costs and benefits associated with different options that vary in terms of reward
magnitude and uncertainty is an adaptive behaviour which allows us to select an optimal course
of action. Previous studies using reversible pharmacological inactivations have shown that the
basolateral amygdala (BLA) to nucleus accumbens (NAc) pathway plays a key role in promoting
choice towards larger, riskier rewards. Neural activity in the BLA and NAc show distinct, phasic
changes in firing prior to action initiation and following action outcomes. Yet, how temporally precise patterns of activity within BLA-NAc circuitry influence choice behaviour is unclear. We
assessed how optogenetic silencing of BLA projection terminals in the NAc altered action
selection during probabilistic decision making. Rats that received intra-BLA infusions of an
AAV encoding for the inhibitory opsin eArchT were well-trained on a probabilistic discounting
task, where they chose between a smaller/certain reward and a larger/riskier reward, with the
probability of obtaining the larger reward changing from 50% to 12.5% across two separate
blocks of trials. During testing, discrete 4-7 second pulses of light were delivered via fiber optic
ferrules into the NAc to suppress activity within BLA terminals during specific task events;
during the period prior to choice or during the outcome immediately following a choice.
Silencing activity of BLA inputs to the NAc prior to choice reduced selection of the more
preferred option, suggesting that at this time, activity within this pathway biases choice towards
more preferred rewards. Silencing during reward omissions increased risky choice during the
low-probability block, indicating that activity in this circuit after non-rewarded actions serves to
modify subsequent choice behaviour. In contrast, silencing during rewarded outcomes did not
reliably affect choice behaviour. Collectively these data demonstrate how patterns of activity in BLA-NAc circuitry convey different types of information that guide optimal action-selection in
situations involving reward uncertainty.Arts, Faculty of
Psychology, Department of
Graduate
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Smith, Kimberley Hazel. « Fast Fourier transform and dynamic imaging of caveolar complex arrays in active striated muscle ». Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8767.
Texte intégralRésumé :
Appendix 2: Movie Clips is supplied as a Zip Archive and will need to be unzipped before viewing. The mechanism of force transfer from contracting sarcomeres to the membrane and endomysium of striated muscle fibres is unclear. The caveolar complex array in striated muscle membranes is a local concentration of cholesterol, sphingomyelin, signalling molecules and the protein caveolin-3. Immunofluorescence microscopy of caveolin-3 in the membrane reveals a regular pattern of fluorescent nodes arranged in longitudinal and transverse rows. The primary aim of this study was to analyse this pattern and how caveolin-3 behaves during contraction. Dynamic imaging and Fast Fourier Transforms (FFTs) were used to study force transmission across the fibre membrane. This pattern was studied in frozen sections of both shortened and rest-length striated muscle fibres. Direct and FFT measurements of spacings between these nodes demonstrated significant reductions in longitudinal measurements in shortened muscle when compared to rest-length muscle. Caveolin-3 nodes lay in register with underlying actin bands in both muscle states, and co-localised with dystrophin. Caveolin-3 was not detectable in C2C12 myoblasts. During differentiation expression became detectable at 2 days. Caveolin-3 was present during myoblast fusion, before forming the regular pattern on the membrane from days 4-5. Fibres became contractile after 5-6 days of development. By 12 days, muscle fibres are 1-2 mm long, multinucleated myotubes with evidence of the caveolin-3 immunofluorescence pattern seen in mature fibres. Knockdown of caveolin-3 expression greatly reduced the number of differentiated myotubes at 12 days. This pattern was not demonstrated in contracting myotubes, possibly owing to lack of permeability to the antibody. The results are consistent with the hypothesis that the force of contraction is transferred across the whole membrane rather than at fibre distal ends.
Livres sur le sujet "Striatum Dynamics"
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Miller, Robert, 1943 Aug. 29- et Wickens J, dir. Brain dynamics and the striatal complex. Amsterdam, Netherlands : Harwood Academic, 2000.
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Wickens, J. R. Brain Dynamics and the Striatal Complex. Sous la direction de R. Miller. Abingdon, UK : Taylor & Francis, 2000. http://dx.doi.org/10.4324/9780203304914.
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Aminoff, Tatiana. Muscle mass and age as factors influencing physical work capacity and strain in dynamic exercise. Helsinki : Finnish Institute of Occupational Health, 1999.
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Robert, Miller, et Jeffrey Wickens. Brain Dynamics and the Striatal Complex. Taylor & Francis Group, 2000.
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Robert, Miller, et Jeffrey Wickens. Brain Dynamics and the Striatal Complex. Taylor & Francis Group, 2000.
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Robert, Miller, et Jeffrey Wickens. Brain Dynamics and the Striatal Complex. Taylor & Francis Group, 2000.
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Robert, Miller, et Jeffrey Wickens. Brain Dynamics and the Striatal Complex. Taylor & Francis Group, 2000.
Trouver le texte intégralChapitres de livres sur le sujet "Striatum Dynamics"
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Martin-Negrier, Marie-Laure, Céline Guigoni, Bertrand Bloch et Erwan Bézard. « Regulation of G-Protein-Coupled Receptor (GPCR) Trafficking in the Striatum in Parkinson’s Disease ». Dans Cortico-Subcortical Dynamics in Parkinson¿s Disease, 1–9. Totowa, NJ : Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-252-0_17.
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Day, Michelle, et D. James Surmeier. « Striatal Dendritic Adaptations in Parkinson’s Disease Models ». Dans Cortico-Subcortical Dynamics in Parkinson¿s Disease, 1–17. Totowa, NJ : Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-252-0_4.
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Podlubnaya, Zoya A. « Composition and Structural Dynamics of Vertebrate Striated Muscle Thick Filaments ». Dans Structure and Dynamics of Confined Polymers, 295–309. Dordrecht : Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0401-5_18.
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Shevelev, Igor A., Konstantin A. Saltykov et George A. Sharaev. « Geometric model of orientation tuning dynamics in striate neurons ». Dans Biological and Artificial Computation : From Neuroscience to Technology, 54–60. Berlin, Heidelberg : Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/bfb0032463.
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Shindou, Tomomi, Gordon W. Arbuthnott et Jeffery R. Wickens. « Neuromodulation and Neurodynamics of Striatal Inhibitory Networks : Implications for Parkinson’s Disease ». Dans Cortico-Subcortical Dynamics in Parkinson¿s Disease, 1–11. Totowa, NJ : Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-252-0_14.
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West, Anthony R., Stephen Sammut et Marjorie A. Ariano. « Striatal Nitric Oxide–cGMP Signaling in an Animal Model of Parkinson’s Disease ». Dans Cortico-Subcortical Dynamics in Parkinson¿s Disease, 1–14. Totowa, NJ : Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-252-0_11.
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Graybiel, Ann M. « Templates for Neural Dynamics in the Striatum : Striosomes and Matrisomes ». Dans Handbook of Brain Microcircuits, sous la direction de Gordon M. Shepherd et Sten Grillner, 133–42. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190636111.003.0012.
Texte intégralRésumé :
The striatum appears to be a relatively simple forebrain region compared to the overlying neocortex, with its horizontal layers and vertical columns. In fact, the striatum in mammals has a sophisticated architecture of its own. This large subcortical region is now suspected of having a major influence on how the neocortex carries out its own functions—even functions related to human language. Furthermore, abnormalities in the striatum are increasingly being discovered in human disorders affecting both cognitive and motor functions. It is, as a consequence, increasingly difficult to see the neocortex as a higher structure and the striatum as a lower structure in terms of their influence on behavior. The chapter is not a full review of this topic, but it points out some findings from the author’s laboratory that hint at such functions for the striosomal system.
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« Adaptive Classification of Cortical Input to the Striatum by Competitive Learning ». Dans Brain Dynamics and the Striatal Complex, 177–90. CRC Press, 2000. http://dx.doi.org/10.1201/9781482283556-13.
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« Insights from Gene Regulation into the Functional Role of Dopamine in the Striatum ». Dans Brain Dynamics and the Striatal Complex, 191–206. CRC Press, 2000. http://dx.doi.org/10.1201/9781482283556-14.
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« The Amygdaloid Complex : Input Processor for the Midbrain Dopaminergic Nuclei and the Striatum ». Dans Brain Dynamics and the Striatal Complex, 89–122. CRC Press, 2000. http://dx.doi.org/10.1201/9781482283556-9.
Texte intégralActes de conférences sur le sujet "Striatum Dynamics"
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Zhou, Bingqian, Kuikui Fan et Lingjie Kong. « A biocompatible hydrogel-coated fiber-optic probe for monitoring pH dynamics in brains of freely moving mice ». Dans Optical Fiber Sensors. Washington, D.C. : Optica Publishing Group, 2022. http://dx.doi.org/10.1364/ofs.2022.w4.69.
Texte intégralRésumé :
The pH dynamics in the brain microenvironment is related to a variety of brain diseases, so it is critical to develop pH probes with great efficiency for in vivo detection of brain. Here, we report a biocompatible hydrogel-coated fiber optic probe (HCFOP) for monitoring pH dynamics in the brains of freely-moving mice. The novel pH probe was prepared by combining hydrogel coated silica multimode fiber with pH-sensitive microspheres embedded in hydrogel fiber, and the pH calibration is based on fluorescence ratio detection. The sensor has a dynamic range of pH from 3.0 to 9.0, and a resolution of 0.0014 pH units with good reproducibility, reversibility, and time stability. We tested the capability of our proposed sensor in dynamically detecting pH in the brains of free moving mice, and the biocompatibility for long-term implantation. We implanted the fiber-optic probes into the striatum and hippocampus of mouse brains. During cerebral ischemia, we detected a decrease in pH of about 0.5 after ~15 mins. During epilepsy induced by kanic acid (KA), we found that pH in the hippocampus decreased by about 0.2 after ~80 mins, in relation to the dynamical concentrations of adenosine. This biofriendly and easy-to-manufacture HCFOP provides a unique solution for assessing small changes in the pH of the brain microenvironment, thus holds great promises in neuroscience study.
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Wood, J. E. « On statistical-mechanical models for the molecular dynamics of striated muscle ». Dans Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 1988. http://dx.doi.org/10.1109/iembs.1988.94680.
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Heeger, David J., et Edward H. Adelson. « Nonlinear model of cat striate physiology ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tut2.
Texte intégralRésumé :
Linear subband image transforms, composed of banks of linear filters tuned to various spatiotemporal frequencies, have been proposed as models of simple cells in striate cortex. Energy measures, composed of the squared sum of the outputs of quadrature pairs of linear filters, have been proposed as models of complex cells. However, given that neurons have a limited dynamic range, the squaring nonlinearity is unreasonable. Thus, we (and others) have proposed that automatic gain control (AGC), mediated by nonlinear (multiplicative) feedback of the contrast signal, plays an important role in striate physiology.
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Baltoiu, Andra, Alexandru Nistorescu, Pierre de Hillerin, Mirel Vasiliu, Vlad Valeanu, Tudor Ion et Calin Marin. « Preliminary qualitative analysis of mechanical impulse propagation dynamics in human striated muscle ». Dans 2015 E-Health and Bioengineering Conference (EHB). IEEE, 2015. http://dx.doi.org/10.1109/ehb.2015.7391413.
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Shukla, Amit, Ashutosh Mani, Amit Bhattacharya et Fredy Revilla. « Classification of Postural Response in Parkinson’s Patients Using Support Vector Machines ». Dans ASME 2013 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/dscc2013-3888.
Texte intégralRésumé :
Parkinson’s disease (PD) is a neurodegenerative condition with neuronal cell death in the substantia nigra and striatal dopamine deficiency that produces slowness, stiffness, tremor, shuffling gait and postural instability. More than 1 million people in North America are affected by PD resulting in balance problems and falls. It is observed that postural instability and gait problems become resistant to pharmacologic therapy as the disease progresses. Furthermore, studies suggest that postural sway abnormalities are worsened by levodopa, the mainstay of therapy for PD. This paper presents a classification of postural balance test data using Support Vector Machines (SVM) to identify the effect of medicine (levodopa) as well as dyskinesia. It is demonstrated that SVM is a useful tool and can complement the widely accepted (but very resource intensive) Unified Parkinson’s Disease Rating Scale (UPDRS).
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Yelamarty, Rao V., Joseph Y. Cheung et Francis T. S. Yu. « LCTV-based hybrid optical-digital processor for the measurement of sarcomere dynamics in an isolated cardiac heart cell ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.thk6.
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Isolated cardiac muscle cells exhibit phasic contractions when they are electrically stimulated and they maintain their distinct AûI band striation pattern, like a one-dimensional diffraction grating, during the contraction–relaxation cycle. This paper demonstrates the application of an on-line, hybrid digital–optical processor, with liquid crystal television (LCTV) serving as a spatial light modulator (SLM), to monitor the dynamics of contraction in real time. The processor, which is interfaced with a phase-contrast microscope, performs a Fourier transformation of the striated cell image optically and records the Fourier spectra digitally by means of a charge-coupled-device camera. A series of digitized images of the Fourier spectra, at intervals of 16.67 ms (noninterlaced frames), is captured during muscle contraction. The sarcomere length at each time point is calculated from centroidal positions of the firstorder diffraction spots. Experimental results demonstrate that LCTV has improved the contrast of striated cell images by 300%. These results suggest that the hybrid processor has a great potential for biomedical applications. Finally, the results obtained from normal and hypertensive heart cells (both with and without drug effects) will be presented.
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Avendaño-Estrada, A., V. M. Lara-Camacho, M. C. Ávila-García et M. A. Ávila- Rodríguez. « Reproducibility of quantitative measures of binding potential in rat striatum : A test re-test study using DTBZ dynamic PET studies ». Dans XIII MEXICAN SYMPOSIUM ON MEDICAL PHYSICS. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4901371.
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Fujime, Satoru. « Dynamic light-scattering study of wormlike chains : β-connectin (titin 2) from striated muscle ». Dans Volga Laser Tour '93, sous la direction de Valery V. Tuchin. SPIE, 1994. http://dx.doi.org/10.1117/12.178994.
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Melnikov, Leonid A., Anna V. Novosselova, Nadejda V. Blinova, Sergey I. Vinitsky, Vladislav V. Serov, Valery V. Bakutkin, T. G. Camenskich et E. V. Guileva. « Potential dynamics of the human striate cortex cerebrum realistic neural network under the influence of an external signal ». Dans Saratov Fall Meeting '99, sous la direction de Vladimir L. Derbov, Leonid A. Melnikov et Vladimir P. Ryabukho. SPIE, 2000. http://dx.doi.org/10.1117/12.380134.
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Biddell, Kevin M., et Jeffrey D. Johnson. « The effects of NMDA receptor model time dynamics over the short and long term when set to striatal dorsolateral and ventromedial medium spiny neurons ». Dans 2013 6th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2013. http://dx.doi.org/10.1109/ner.2013.6696141.
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