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1
Adams, Niels C. "An investigation of the rat's perireticular nucleus and its possible role in the formation of corticofugal and corticopetal connections." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308700.
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Thomas, Francis Tyson, and Francis Tyson Thomas. "Fast Automatic Segmentation of Thalamic Nuclei." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/626390.
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Fast, automated segmentation of the thalamic nuclei in the brain has long been desired as it provides for direct visualization of the target for certain procedures like Deep Brain Stimulation (DBS) that target a specific nucleus. It is also beneficial in the study of other pathologies that pertain to different nuclei.
In this thesis, a novel approach to fast automated segmentation of thalamic nuclei called Shortened Template and THalamus for Optimal Multi Atlas Segmentation (ST THOMAS) was developed using the multi-atlas segmentation approach. It was designed with a focus on robustness and speed by making use of an averaged template for registration and cropping the inputs and the template.
The performance of ST THOMAS was first evaluated on 7T MRI data by comparing with manual delineation (ground truth) by an expert neuroradiologist. Dice coefficients and Volumetric Similarity Indices were used as metrics. To extend the applicability of this method, 3T MRI data were also evaluated. Finally, applications to real time ventralintermideiate (VIM) nucleus targeting for DBS and study of the effects of alcoholism are demonstrated.
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Zenk, Nina [Verfasser]. "Elektrophysiologischer Vergleich von Globus pallidus internus und Thalamus und elektrophysiologisches und anatomisches Mapping des ventrolateralen Thalamus / Nina Zenk." Köln : Deutsche Zentralbibliothek für Medizin, 2016. http://d-nb.info/1100700072/34.
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Kiss, Zelma H. T. "Plasticity in the adult human somatosensory thalamus." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ35206.pdf.
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翁德心 and Tak-sum Yung. "Expression of GABAA receptor alpha-1 subunit in thalamic neurons responsive to vertical linear acceleration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42610059.
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Yung, Tak-sum. "Expression of GABAA receptor alpha-1 subunit in thalamic neurons responsive to vertical linear acceleration." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42610059.
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Kwon, Young Ha 1962. "Functional role of neurotransmitters in the visual thalamus." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13524.
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HOWARD, JENNIFER DIXON. "DEVELOPMENT OF THE AUDITORY THALAMUS IN THE FERRET." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022254330.
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Pigeat, Romain. "Plasticité intrathalamique des synapses inhibitrices : implication des canaux calciques de type T dans la LTD des synapses NRT-TC lors des rythmes du sommeil profond." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066463/document.
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Le thalamus, via les neurones glutamatergiques thalamocorticaux (TC), est le dernier relai dans le cheminement des informations de la périphérie vers le cortex. Le réseau intrathalamique repose sur les interactions entre ces neurones TC et des neurones GABAergiques regroupés dans le Noyau Réticulé Thalamique (NRT). Ces deux types de neurones contribuent au traitement des informations issues de la périphérie et à la genèse des activités oscillantes pendant le sommeil. Pendant les phases de sommeil à ondes lentes les neurones TC et NRT émettent de manière périodique et synchrone des bouffées de potentiels d'action à haute fréquence associées à de forts influx de calcium dus à l'activation des canaux calciques de type T. Au cours de ma thèse, j'ai cherché à déterminer si ces activités étaient susceptibles de modifier la force synaptique. En utilisant un protocole d'induction mimant l'excitabilité des neurones thalamiques durant le sommeil à ondes lentes, j'ai mis en évidence une dépression à long terme (LTD) de la synapse GABAergique entre les neurones NRT et TC. J'ai montré que cette LTD était d'origine post-synaptique et nécessitait en synergie 1) l'activation des récepteurs GABAA présents à la synapse, 2) une forte entrée de calcium dans les neurones TC spécifiquement par les canaux calciques de type T, 3) l'activation des récepteurs métabotropiques du glutamate. L'exigence d'une entrée massive de calcium par les canaux calciques de type T suggère que seules les activités thalamocorticales associées au sommeil à ondes lentes sont susceptibles de déclencher cette LTDThalamocortical (TC) glutamatergic neurons from the thalamus are the last relay in the flow of information from the periphery to the cortex. Intrathalamic network is based on the interactions between these TC neurons and the GABAergic neurons located in the Thalamic Reticularis Nucleus (TRN). These two types of neurons contribute to the processing of information arising from the periphery and to the generation of oscillatory activities during sleep. During slow-waves-sleep, NRT and TC neurons discharge rhythmically and synchronously high frequency bursts of action potentials associated with calcium influx occurring through T-type calcium channels. During my thesis, I sought to determine whether these activities were capable of changing synaptic strength. Using an induction protocol mimicking the excitability of thalamic neurons during slow-wave sleep, I highlighted a long-term depression (LTD) of the synapse between NRT GABAergic neurons and TC neurons. I showed that LTD induction had a postsynaptic origin and required synergistically 1) the synaptic activation of GABAA receptors, 2) a high calcium entry in TC neurons specifically through T-type calcium channels 3) the activation of metabotropic glutamate receptors. The requirement of calcium influx through the T-type calcium channels suggests that only thalamocortical activities associated with slow wave sleep may trigger this LTD
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Petrof, Iraklis. "Behavioural analysis of the role of caudal thalamic reticular nucleus in attention /." St Andrews, 2007. http://hdl.handle.net/10023/373.
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Chen, Chao-Chen. "Role of VPM thalamus in mechanical sensitivity and hyperalgesia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ48754.pdf.
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Unrath, Alexander. "Richtungsabhängige Farbcodierung des menschlichen Thalamus mittels Diffusion Tensor Imaging." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-59832.
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Monavarfeshani, Aboozar. "Mechanisms underlying retinogeniculate synapse formation in mouse visual thalamus." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/81893.
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Retinogeniculate (RG) synapses connect retinal ganglion cells to the thalamic relay cells of the dorsal lateral geniculate nucleus (dLGN). They are critical for regulating the flow of visual information from retina to primary visual cortex (V1). RG synapses in dLGN are uniquely larger and stronger than their counterparts in other retinorecipient regions. Moreover, in dLGN, RG synapses can be classified into two groups: simple RG synapses, which contain glia-encapsulated single RTs synapsing onto relay cell dendrites, and complex RG synapses, which contain numerous RTs that converge onto the shared regions of relay cell dendrites. To identify target-derived molecules that direct the transformation of RTs into unique RG synapses in dLGN, I used RNAseq to obtain the whole transcriptome of dLGN and its adjacent retinorecipient nucleus, vLGN, at different time points during RG synapses development. Leucine-Rich Repeat Transmembrane Neuronal 1 (LRRTM1), a synaptogenic adhesion molecule, was the candidate I selected based on its expression pattern. Here, I discovered that LRRTM1 regulates the development of complex RG synapses. Mice lacking LRRTM1 (lrrtm1-/-) not only show a significant reduction in the number of complex RG synapses but they exhibit abnormal visual behaviors. This work reveals, for the first time, a high level of retinal convergence onto dLGN relay cells in thalamus and the functional significance of this convergence for vision.Ph. D.
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Asavaritikrai, Pundit. "Regulation of programmed cell death in the developing thalamus." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/24709.
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In this thesis, I examined PCD in the thalamus during the period of innervation of the cortex (late embryonic to early postnatal ages in mice). I found that apoptosis (revealed by TUNEL and pyknotic morphology) is a common mode of thalamic PCD both in vivo and in vitro. In vivo studies showed the highest rate of cell death is in early postnatal life, at postnatal day 1 (P1). In vivo analysis of animals lacking functional neurotrophin tyrosine kinase receptors, TrkB and TrkC, and in vitro work in collaboration with Dr Beau Lotto showed that brain-derived neurotrophic factor (BDNF), acting via TrkB, regulates thalamic survival in the perinatal period. My in vitro studies showed that thalamic cells cultured from E15 for up to 5 days showed a loss of viability after 2-3 days, which precedes the in vivo increase in thalamic PCD. Cortical factors in addition to BDNF are able to maintain thalamic viability for longer periods in culture. Later studies showed that these factors are not unique to the cerebral cortex but can be found in other neuronal tissues. Amongst other tissues, the late-gestation thalamus is able to produce them provided it is stimulated with elevated levels of K+. Elevated K+ is known to promote thalamic survival by increasing depolarisation but I found evidence that elevated K+ did not require TrkB or TrkC signaling to produce a trophic effect since K+ had normal trophic effects on the thalamic explants of either trkB (-/-) or trkC (-/-) animals. Moreover, I observed an increased cell death in the E19 thalamus in mice homozygous for a mutation of the transcription factor pax-6. This mutant is known to lack thalamocortical innervation and my in vivo and in vitro analysis of this mutant, suggested that thalamocortical innervation is essential for developing thalamic cells to obtain sufficient trophic factors.
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Dacre, Joshua Rupert Heaton. "Thalamic control of motor behaviour." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29530.
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The primary motor cortex (M1) is a key brain area for the generation and control of motor behaviour. Output from M1 can be driven in part by long-range inputs from a collection of thalamic nuclei termed the motor thalamus (MTh), but how MTh input shapes activity in M1 and forelimb motor behaviour remains largely unresolved. To address this issue, we first defined the 3D anatomical coordinates of mouse forelimb motor thalamus (MThFL) by employing conventional retrograde and virus-based tracing methods targeted to the forelimb region of M1 (M1FL). These complimentary approaches defined MThFL as a ~0.8 mm wide cluster of neurons with anatomical coordinates 1.1 mm caudal, 0.9 mm lateral to bregma and 3.2 mm below the pial surface. Thus, MThFL incorporates defined areas of the ventrolateral, ventral anterior and anteromedial thalamic nuclei. To investigate the importance of M1FL and MThFL during skilled motor behaviour, we developed and optimised a quantitative behavioural paradigm in which head-restrained mice execute forelimb lever pushes in response to an auditory cue to receive a water reward. Forelimb movement trajectories were mapped using high-speed digital imaging and multi-point kinematic analysis. We inactivated both M1FL and MThFL of mice performing this motor behaviour using a pharmacological strategy, which in both cases resulted in a significant reduction in task performance. Inactivating M1FL significantly affected forelimb coordination and dexterity, resulting in erratic motion and posture. In contrast, mice with MThFL inactivated displayed a reduction in total motor output, although correct posture was maintained. We performed extracellular recordings in MThFL of expert-level mice, demonstrating that motor thalamic output during execution of task was dominated by a robust response to the onset of the auditory cue. Cue-evoked responses were also observed in motor thalamic neurons of naive mice. We have developed a novel solution to the stability problem encountered when performing whole-cell patch-clamp recordings from the motor cortex of head-restrained mice performing forelimb motor behaviour, and present preliminary recordings maintained through the execution of forelimb behaviour.
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Seifert, Sebastian. "Die Bedeutung des Thalamus für das menschliche Handlungsüberwachungssystem im fronto-striato-thalamo-corticalen Netzwerk." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-100297.
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Für das zielgerichtete Verhalten des Menschen ist ein funktionierendes Handlungsüberwachungssystem eine wichtige Voraussetzung. Somit können Fehlhandlungen registriert und verarbeitet werden, um dann anschließend das Verhalten an die entsprechende Situation besser anzupassen. Ein wichtiges neuroanatomisches Korrelat dieses Handlungsüberwachungssystems ist der anteriore Anteil des mittleren cingulären Cortex (anterior midcingulate cortex, aMCC), der in der Funktion der Fehlerverarbeitung eng mit den Basalganglien und dem lateralen präfrontalen Cortex verknüpft ist. In der vorliegenden Arbeit wurde die Bedeutung des Thalamus im Netzwerk der Fehlerverarbeitung genauer untersucht. Es konnte mittels diffusionsgewichteter Traktografie bei 16 gesunden Probanden gezeigt werden, dass speziell der Nucleus ventralis anterior (VA) und der Nucleus ventralis lateralis anterior (VLa) quantitativ stärkere Faserverbindungen mit dem aMCC aufweisen, als die restlichen Thalamuskerne. Desweiteren zeigten 15 Patienten mit Läsionen im Thalamus im Vergleich zur gesunden Kontrollgruppe im Eriksen Flanker Task fehlerspezifische Verhaltensunterschiede. Obwohl die Fehlerrate zwischen diesen Patienten und den Kontrollprobanden nahezu identisch war, konnten die Patienten ihre Fehler als solche signifikant schlechter detektieren und ihr Verhalten nach einem Fehler daher auch schlechter anpassen. Die EEG Daten zeigten für die Patientengruppe eine in der Amplitude signifikant verminderte error-related negativity (ERN – ein ereignis-korreliertes Hirnpotential, ausgelöst durch Fehlhandlungen, z.B. in Flankierreizaufgaben) im Vergleich zur Kontrollgruppe. Bei 6 Patienten mit Läsionen der VA und VLa Kerngruppe war die ERN nahezu komplett erloschen, wohingegen bei den 9 Patienten, deren Läsionen nicht VA und VLa betrafen, die ERN lediglich vermindert warPerformance monitoring is an essential prerequisite of successful goal-directed behavior. Research of the last two decades implicates the anterior midcingulate cortex (aMCC) in the human medial frontal cortex and frontostriatal basal ganglia circuits in this function. Here, we addressed the function of the thalamus in detecting errors and adjusting behavior accordingly. Using diffusion-based tractography we found that, among the thalamic nuclei, the ventral anterior and ventral lateral anterior nuclei (VA, VLa) have the relatively strongest connectivity with the RCZ. Patients with focal thalamic lesions showed diminished error-related negativity, behavioral error detection, and post-error adjustments. When the lesions specifically affected the thalamic VA/VLa nuclei these effects were significantly pronounced, which was reflected by complete absence of the error-related negativity. These results reveal that the thalamus, particularly its VA/VLa region, is a necessary constituent of the performance-monitoring network, anatomically well connected and functionally closely interacting with the aMCC
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Petrof, Iraklis. "Behavioural investigation of the role of caudal thalamic reticular nucleus in attention." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/373.
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The thalamic reticular nucleus (TRN), and especially its caudal, sensory-related, half (cTRN), has been hypothesised for years to be at the very heart of thalamic sensory processing modulation, and attentional processes in particular. Very limited behavioural evidence is available, nonetheless, in support of such a functional attribution. In this thesis we carried out a series of investigations, combining immunocytochemical and lesion techniques with tests of behaviour, in order to examine the potential role of cTRN in attention and identify the attentional processes, if any, that it is more likely to contribute to. In chapter II, we looked at the Fos activation levels within modality-specific sectors of cTRN following attentive behaviours to stimulation of different modalities. We observed a selective activation of the visual sector of cTRN in visually attentive animals but not in tactilely attentive, yet visually stimulated, animals, thus demonstrating an involvement of that area in processes of visual attention. In chapter III we looked at the role of cTRN in cross-modal expressions of divided attention. We found that its removal, through neurotoxic lesioning, did not result in any behavioural costs with regard to the division of attention. Detriments in response accuracy, however, suggested that cTRN may be involved in stimulus processing enhancement operations, unrelated with the division of attention. Finally, in chapters IV and V, we looked at the effects of lesions of the visual sector of cTRN (TRNvis) on the ability to orient attention covertly within visual space. We found that the removal of TRNvis did not affect visual covert orienting behaviour, both when this is triggered by exogenous and endogenous means. Overall our results suggest that even though cTRN appears to be involved in some aspects of attention, it does not represent a necessary structure for the generation and operation of certain other forms of attention.
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Cetas, Justin Schultz. "Neuronal architecture and functional organization of the rabbit auditory thalamus." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284260.
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The ventral division of the medial geniculate body (MGV) is the primary tonotopically-organized nucleus of the auditory thalamus. Previous studies have suggested a close association between the anatomical structure of the MGV and its observed functional organization, but direct correlative studies are lacking. In the present study, regional differences in the cytoarchitecture of the rabbit MGV were described. These different regions were shown to have distinct frequency organizations. The central portion of the rabbit MGV is characterized by a laminated cytoarchitecture that is formed from the orderly arrangement of highly-oriented neuronal cell bodies. In this region, there exists a steep frequency gradient that extends across the dorso-ventral axis of the nucleus, orthogonal to the cellular laminae. This frequency gradient is marked by a discontinuous and stepwise-progression of best frequency. In regions lacking a laminated cytoarchitecture, a steep frequency gradient is absent. In addition, the morphology and basic response properties of individual cells were studied with the juxtacellular labeling technique. Two morphological types of projection neurons as well as two types of putative interneurons were identified on the basis of dendritic thickness, cell soma size and spine morphology. Both types of tufted projection neurons had a variety of different response properties, but the Onset pattern and summation response to binaural stimulation predominate. Quantitative spatial analyses demonstrated that the dendritic fields of both types of tufted neurons are highly oriented. Further, for neurons within the laminated portion of the nucleus, the major axis of orientation of the dendritic fields are parallel to the cellular laminae and orthogonal to the frequency gradient. Departures from this orientation parallel changes in Nissl and functional architecture. A model is presented that correlates the discontinuous and step-wise frequency gradient in the nucleus with the size and morphology of dendritic fields. Lastly, three-dimensional reconstructions of anterogradely-labeled thalamocortical axons reveal a novel class of thalamocortical axon that has collaterals to both layer I as well as layers III/IV of primary auditory cortex; these layers were previously thought to have exclusively separate inputs. This novel class of axon is further evidence for multiple parallel channels from the MGV to AI.
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Lacey, Carolyn Jane. "The neural networks interconnecting the basal ganglia and the thalamus." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437355.
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Mitchell, Anna S. "Involvement of the medial thalamus in multiple attributes of memory." Thesis, University of Canterbury. Psychology, 2004. http://hdl.handle.net/10092/4578.
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It is widely regarded that the amnesic deficits associated with diencephalic amnesia and medial temporal lobe amnesia are similar. However, the neural basis of diencephalic amnesia and the contributions of different medial thalamic nuclei continue to prove a contentious issue. Contrary to the view that specific medial thalamic nuclei are responsible for profound amnesia after diencephalic injury in humans, the neural connections associated with three aggregates of thalamic nuclei suggest that they each contribute to independent memory systems. These three aggregates were identified by a review of the neuroanatomical tracing studies from the research literature. One thalamic aggregate comprised of the anterior thalamic nucleus (AT), while the other two consisted of less conventional groupings of medial thalamic nuclei, namely a lateral thalamic group (LT) and a posteromedial thalamic group (MT). The LT aggregate was identified as the rostral intralaminar nuclei (paracentral, centrolateral, and rostral central medial) and the lateral and paralamellar segments of the mediodorsal thalamic nucleus. The MT aggregate was identified as the central and medial segments of the mediodorsal nucleus as well as the intermediodorsal nucleus. The functional contributions to specific attributes of memory were assessed in rats across a variety of behavioural tasks. Highly localised lesions to the MT produced deficits on a reward magnitude task, which previously has been found to be sensitive to amygdala and lateral prefrontal lesions, which supports the view that the MT contributes to an amygdala-based memory system. Only AT lesions produced deficits in spatial memory tasks, which are also sensitive to hippocampal lesions, which confirms earlier evidence that the AT contributes to an extended hippocampal system responsible for spatial memory processing. Only LT lesions produced deficits in an egocentric response memory task, which is also disrupted by dorsomedial prefrontal cortex and dorsal striatum lesions, and which thus supports the notion that the LT is a functional component of a dorsal striatum memory system. In addition, LT and MT lesions, but not AT lesions, impaired temporal order memory, while no lesion impaired object recognition or sustained attention. These new dissociations indicate that distributed neural circuits incorporating many brain structures including the medial thalamus can be identified as contributing to independent learning and memory processes.
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Fénelon, Gilles. "Le complexe central (centre median-parafasciculaire) du thalamus du primate." Paris 6, 1993. http://www.theses.fr/1993PA066363.
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Le complexe central (centre median-parafasciculaire) du thalamus connait au cours de la phylogenese un important developpement. Chez le primate, il apparait subdivise en trois parties. Les criteres cytoarchitectoniques classiques sont insuffisants pour les delimiter. L'etude quantitative de la morphologie neuronale montre que les trois subdivisions sont faites de types neuronaux distincts. Les connexions de la partie mediale du complexe (pars parafascicularis) sont incompletement etablies. Elle projette sur le territoire associatif du striatum et a des connexions avec des structures impliquees dans l'oculomotricite. La partie intermediaire (pars media) appartient a la boucle de nauta et mehler: elle recoit une afference du territoire sensori-moteur du pallidum medial, et projette sur le territoire sensori-moteur du striatum. La partie laterale (pars paralateralis) a tres peu de connexions avec les ganglions de la base. Pars media et pars paralateralis sont toutes deux en relation reciproque avec le cortex moteur. Le complexe central a en commun avec la plupart des autres noyaux thalamiques d'etre reciproquement relie a la formation perithalamique et a certaines regions corticales. Il se distingue toutefois par ses types neuronaux et ses rapports avec les ganglions de la base. Ni l'experimentation animale, ni la neuropathologie, ni les essais chez l'homme de lesion stereotaxique n'ont permis d'elucider le role du complexe central. Ses connexions suggerent un role moteur et permettent de l'inclure dans le systeme des ganglions de la base
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Ontaneda, Daniel. "MAGNETIC RESONANCE FINGER PRINTING OF THE THALAMUS IN MULTIPLE SCLEROSIS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case15856775860965.
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Ye, Zhiwen. "Transgenic and optogenetic manipulation of inhibition in mouse visual thalamus." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/30628.
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This thesis examines GABAA receptor (GABAAR) and GABAB receptor (GABABR) mediated inhibition within the mouse dorsal lateral geniculate nucleus (dLGN) with a particular emphasis on the significance of GABA release from local interneurons. The removal of the gamma2 subunit from thalamic relay neurons of the dLGN in the HDC-gamma2 mouse strain was shown to reduce the overall sIPSC frequency across all relay neurons with an absence of IPSCs in a subset of Y-type thalamic relay neurons. The IPSCs associated with the remaining relay neurons exhibited slower rise-times and decays and were insensitive to diazepam, indicating the absence of the gamma2 subunit. Potentiation of these slower IPSCs by DMCM further suggested that the remaining IPSCs were mediated by gamma1 subunit-containing GABAA receptors. In contrast, removal of the GABAB1 subunit resulted in a complete loss of postsynaptic GABABR responses within the mouse dLGN in all cells so far examined. The baclofen-induced membrane hyperpolarization was lost from HDC-GABAB1 cells and elevated ambient GABA concentrations resulted in a significantly smaller membrane hyperpolarization. Although HDC-GABAB1 mice did not exhibit a major visual deficit in a novel object recognition task, local field potential recordings during the animals sleep period revealed a shift in the power spectrum towards 1-4 Hz delta band of oscillatory activity locally within the visual cortex. I also identified the Sox14 gene as a marker for dLGN interneurons. Channelrhodopsin-2 (ChR2) activation of Sox14 interneurons not only gave rise to time-locked phasic inhibition in the dLGN relay neurons, this stimulation also induced tonic inhibition in an activity-dependent manner, mediated by the activation of extrasynaptic delta-containing GABAARs. However, action potential induced GABA release from interneuron is not a conspicuous feature of simultaneous paired interneuron to relay neuron recordings.
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Pirttimäki, T. M. "Astrocyte-neuron signalling by synaptic stimulation in the ventrobasal thalamus." Thesis, Aston University, 2009. http://publications.aston.ac.uk/15371/.
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In the Ventrobasal (VB) thalamus, astrocytes are known to elicit NMDA-receptor mediated slow inward currents (SICs) spontaneously in neurons. Fluorescence imaging of astrocytes and patch clamp recordings from the thalamocortical (TC) neurons in the VB of 6-23 day old Wistar rats were performed. TC neurons exhibit spontaneous SICs at low frequencies (~0.0015Hz) that were inhibited by NMDA-receptor antagonists D-AP5 (50µM), and were insensitive to TTX (1µM) suggesting a non-neuronal origin. The effect of corticothalamic (CT) and sensory (Sen) afferent stimulation on astrocyte signalling was assessed by varying stimulus parameters. Moderate synaptic stimulation elicited astrocytic Ca2+ increases, but did not affect the incidence of spontaneous SICs. Prolonged synaptic stimulation induced a 265% increase in SIC frequency. This increase lasted over one hour after the cessation of synaptic stimulation, so revealing a Long Term Enhancement (LTE) of astrocyte-neuron signalling. LTE induction required group I mGluR activation. LTE SICs targeted NMDA-receptors located at extrasynaptic sites. LTE showed a developmental profile: from weeks 1-3, the SIC frequency was increased by an average 50%, 240% and 750% respectively. Prolonged exposure to glutamate (200µM) increased spontaneous SIC frequency by 1800%. This “chemical” form of LTE was prevented by the broad-spectrum excitatory amino acid transporter (EAAT) inhibitor TBOA (300µM) suggesting that glutamate uptake was a critical factor. My results therefore show complex glutamatergic signalling interactions between astrocytes and neurons. Furthermore, two previously unrecognised mechanisms of enhancing SIC frequency are described. The synaptically induced LTE represents a form of non-synaptic plasticity and a glial “memory” of previous synaptic activity whilst enhancement after prolonged glutamate exposure may represent a pathological glial signalling mechanism.
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Cao, Xiao Yan. "Excitatory actions of orexins in rat paraventricular nucleus of thalamus." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27232.
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The midline thalamic paraventricular nucleus (PVT) receives a unique orexinergic innervation. To address possible function, this investigation used patch clamp recordings in rat brain slice preparations to evaluate intrinsic properties of PVT neurons and neuronal responses to bath-applied orexin peptides (A and/or B). PVT neurons displayed distinct state-dependent burst or tonic firing patterns, time dependent and time-independent inward rectification, T-type currents and low threshold spikes, action potential after-hyperpolarizations, spike frequency adaptation and spike broadening. A majority responded to both orexin peptides with slowly rising and prolonged membrane depolarizations, and inward currents that involved closure of potassium channels and/or opening of nonselective cationic channels. These data imply that endogenously released orexins likely act at both types of orexin receptors that can engage two conductances to modulate and increase neuronal excitability in PVT, a role that may be important for 'arousal' and neurotransmission within this midline thalamic nucleus.
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Rousseau, Charly. "Etude de la transmission inhibitrice mixte GABA/glycine dans le cervelet et le thalamus." Paris 6, 2011. http://www.theses.fr/2011PA066399.
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Dans le système nerveux central des vertébrés, la transmission synaptique inhibitrice rapide est médiée par le GABA et la glycine. Le transporteur vésiculaire des acides aminés inhibiteurs (VIAAT) est capable d'accumuler ces deux neurotransmetteurs dans les mêmes vésicules synaptiques, conduisant fréquemment à leur co-libération. Les travaux présentés ici sont basés principalement sur l'étude de la cellule unipolaire en brosse du vestibulocervelet (CUB). Cette cellule reçoit d'une part des synapses inhibitrices mixtes provenant des cellules de Golgi et d'autre part une unique synapse glutamatergique formée par une fibre moussue. Cette configuration en fait un modèle idéal pour étudier les interactions entre inhibition mixte et excitation. La caractérisation de l'inhibition mixte reçue par les CUBs nous a permis d'en distinguer deux populations, l'une d'entre elles ne recevant pas d'inhibition GABAergique. Cette absence de composante GABAergique est corrélée à la présence de récepteurs métabotropiques au glutamate du groupe II à la synapse excitatrice, établissant un lien inédit entre les phénotypes moléculaires et fonctionnels des synapses inhibitrices mixtes et des synapses glutamatergiques sur un même neurone. La mise au point d'un protocole d'immunohistochimie permettant la détection efficace des récepteurs inhibiteurs aux synapses nous a permis de confirmer et d'étendre ces observations à d'autres structures du système nerveux central. Nous montrons ainsi une grande variété d'organisation moléculaire des synapses inhibitrices dans les noyaux profonds cérébelleux ainsi que dans les noyaux intralaminaires du thalamus.
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Arecchi, Patricia Brigitte. "La connexion pallido-thalamique du primate." Aix-Marseille 2, 2003. http://www.theses.fr/2003AIX22002.
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Danet, Lola. "Recollection et familiarité chez 12 patients présentant un infarctus thalamique gauche : étude comportementale, en imagerie structurale et fonctionnelle de repos." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30335/document.
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La mémoire de reconnaissance nous permet à la fois de détecter rapidement un stimulus précédemment perçu (familiarité), et de récupérer des informations relatives au contexte de notre rencontre avec ce stimulus (recollection). Les modèles neuro-anatomiques d'Aggleton et Brown (1999) puis d'Aggleton et al. (2011) postulent que le noyau antérieur (NA) du thalamus et le tractus mamillo-thalamique (TMT) du fait de leurs connexions avec l'hippocampe font partie du circuit de la recollection tandis que le noyau dorso-médian (DM) participerait à la familiarité en raison de ses connexions avec le cortex périrhinal. Dans cette thèse nous avons testé cette hypothèse d'indépendance. 12 patients avec un infarctus thalamique gauche ont été recrutés ainsi qu'un groupe de sujets contrôles appariés. Tous les participants ont été soumis à un bilan neuropsychologique, à trois tâches expérimentales de mémoire de reconnaissance et à un examen d'IRM morphologique et d'IRM fonctionnelle de repos. Selon les tâches nous avons estimé la contribution de la recollection et de la familiarité à la réponse sur la base de la verbalisation de la source, du degré de confiance dans la réponse ou de la catégorisation des réponses. Les lésions thalamiques ont été quantifiées et localisées automatiquement grâce à une nouvelle approche méthodologique que nous avons développée. Le profil neuropsychologique des patients a mis en évidence une amnésie antérograde verbale et un trouble exécutif modéré (Etude 1). Les lésions atteignaient principalement le DM alors que le NA était intact chez tous. Le TMT était lésé chez les 7 patients les plus amnésiques (Etudes 1 et 2). La recollection était altérée chez les patients quelle que soit la tâche alors que la familiarité était préservée. De plus l'indice de recollection corrélait avec la lésion du DM (Etude 2). Enfin, des corrélations ont été trouvées dans l'étude en connectivité fonctionnelle entre la disconnexion thalamo-frontale et la recollection (Etude 3). En somme, ces résultats signifient i\ qu'une lésion du NA n'est pas nécessaire pour causer une amnésie ii\ qu'une lésion du DM est suffisante pour causer un défaut de recollection mais pas nécessaire pour atteindre la familiarité iii\ qu'une lésion du TMT prédit une amnésie sévère, enfin iv\ que le réseau reliant fonctionnellement le DM au cortex préfrontal semble être impliqué dans l'expérience subjective de la mémoire de reconnaissance plutôt que dans ses contenus. Ils suggèrent de plus que le modèle d'Aggleton et al (2011) devrait être révisé en ce qui concerne la relation familiarité / DMRecognition memory allows determining whether a stimulus has been previously encountered based on either a rapid detection process (familiarity) or a longer retrieval of the context associated with the stimulus (recollection). Aggleton and Brown's model (1999) and Aggleton and colleagues (2011) postulated that recollection and familiarity are anatomically and functionally independent. They hypothesized that the anterior nucleus (AN) / mamillothalamic tract (MTT) complex of the thalamus would be critical for recollection due to its connections with the hippocampus. The Mediodorsal (MD) nucleus would support familiarity owing to its links with the perirhinal cortex. In this thesis we tested this independence hypothesis. The 12 subjects with a pure left thalamic infarction were included along with a healthy matched control group. Every subject underwent a neuropsychological assessment, three experimental verbal recognition memory tasks, a high-resolution structural volumetric MRI scan and resting state functional imaging. Recollection and familiarity estimations were derived from subjective reports or responses categorization. We specifically developed the methods used to automatically analyse the volume and localization of the lesions. Patients performed worse than controls on verbal memory and to a lesser extent on executive tasks (Study 1). Most of the lesions were located in the MD while no lesion of the AN was found. The seven patients exhibiting MTT damage had the lowest memory performance (Studies 1 and 2). Recollection was lower in patients than in controls in all the three tasks whereas familiarity was systematically normal. In addition we found a significant correlation between the recollection index and the DM damage, suggesting that DM is directly involved in recollection (Article 2). Finally the functional connectivity results showed a correlation between recollection and a pattern of thalamofrontal disconnection in the patients, helping to understand the DM-recollection relationship. Overall, the findings of the different studies mean that i\ AN damage is rare and is not necessary to cause an amnesia, ii\ MD damage is sufficient to cause a recollection impairment but not necessary to impair familiarity, iii\ MTT damage predicts the severity of the amnesia, iv\ the network linking functionally the MD with the prefrontal cortex seems to be involved in the subjective experience associated with recognition memory
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Peter-Derex, Laure. "Les micro-éveils chez l'homme : étude par enregistrements intracérébraux." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10314/document.
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Trois états de vigilance, caractérisés par une activité cérébrale spécifique, sont habituellement décrits chez l'Homme: la veille, le sommeil lent et le sommeil paradoxal. Cependant, certaines situations cliniques comme les parasomnies ou l'inertie de sommeil, ainsi que des travaux expérimentaux récents chez l'animal et chez l'homme, suggèrent la possibilité d'états intermédiaires ou transitionnels. L'étude des micro- éveils apparait pertinente pour appréhender les phénomènes de transition entre états de vigilance. Pour caractériser les micro-éveils chez l'Homme, nous avons enregistré l'activité EEG au cours de micro-éveils "spontanés" ou déclenchés par des stimulations nociceptives, en sommeil lent et en sommeil paradoxal, chez 8 patients épileptiques pharmaco-résistants bénéficiant d'un bilan pré-chirurgical invasif stéréo-électro- encéphalographique. Les puissances spectrales dans différentes bandes de fréquence au cours des micro-éveils ont été comparées à celles déterminées sur le signal précèdant le micro-éveil. Le thalamus (pulvinar médian), le cortex sensorimoteur primaire et plusieurs aires corticales associatives ont été étudiés. Nous avons observé 1) une grande reproductibilité intra et interindividuelle des modifications d'activité EEG associées aux micro-éveils dans le thalamus, et qui correspondent à un état intermédiaire entre la veille et le sommeil. 2) une importante hétérogénéité des modes d'activation corticale au cours des micro-éveils, quand bien même l'activation sous- corticale est stéréotypée. Différents facteurs participent à cette variabilité : le cortex considéré, le stade de sommeil au cours duquel le micro-éveil survient, la nature du stimulus à l'origine du micro-éveil, ou encore des phénomènes homéostatiques. 3) que la composition spectrale du signal au cours des micro-éveils dansle cortex était différente de l'état de veille, ce qui situe les micro-éveils hors du spectre des états de vigilance classiquement différenciés et constitue un argument en faveur du fait que la transition entre le sommeil et la veille au niveau cortical ne se fait pas de façon abrupte et binaire. Ainsi, les micro-éveils apparaissent comme des états d'activation cérébrale régulés au moins en partie localement par des mécanismes impliqués dans la gestion d'une double nécessité théoriquement contradictoire : permettre au dormeur de réagir à des stimulations pertinentes, tout en préservant la continuité du sommeilWakefulness, non rapid eye movement (NREM) and rapid eye movement (REM) sleep are characterized by specific brain activities. However, recent experimental findings as well as various clinical conditions (parasomnia, sleep inertia) have revealed the presence of transitional states. Brief intrusions of wakefulness into sleep, namely arousals, appear as relevant phenomena to characterize how brain commutes from sleep to wakefulness. Using intra-cerebral recordings in 8 drug-resistant epileptic patients we analyzed electroencephalographic (EEG) activity during spontaneous or nociceptive-induced arousals in NREM and REM sleep. Wavelet spectral analyses were performed to compare EEG signals during arousals, sleep and wakefulness, simultaneously in the thalamus, and primary, associative or high order cortical areas. We observed that: 1) thalamic activity during arousals is stereotyped and its spectral composition corresponds to a state in-between wakefulness and sleep 2) patterns of cortical activity during arousals are heterogeneous, their manifold spectral composition being related to several factors such as sleep stages, cortical areas, arousal modality ("spontaneous" vs nociceptive-induced) and homeostasis; 3) spectral compositions of EEG signals during arousal and wakefulness differ from each other. Thus, stereotyped arousals at the thalamic level seem to be associated with different patterns of cortical arousals due to various regulation factors. These results suggest that human cortex does not shift from sleep to wake in an abrupt binary way. Arousals may be considered more as different states of the brain than as "short awakenings". This phenomenon may reflect the mechanisms involved in the compromise needed to be found between two main contradictory functional necessities, preserving the continuity of sleep and maintaining the possibility to react
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Wahl, Michael. "Syntaktische und semantische Verarbeitung auditorisch präsentierter Sätze in kortiko-basalen Hirnstrukturen : eine EKP-Studie." Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2007/1424/.
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Seit den Anfängen empirisch-neurowissenschaftlicher Forschung gilt Sprachkompetenz zuvorderst als eine Leistung der Hirnrinde (Kortex), jedoch wurden v. a. im Zuge sich verbessernder bildgebender Verfahren aphasische Syndrome auch nach Läsionen subkortikaler Hirnregionen, insbesondere der Basalganglien und des Thalamus nachgewiesen. Diese Strukturen liegen in der Tiefe des Gehirns und kommunizieren über weit gefächerte Faserverbindungen mit dem Kortex.
In erster Linie werden den Basalganglien senso-motorische Kontrollfunktionen zugewiesen. Dementsprechend werden diverse Erkrankungen, die durch Störungen physiologischer Bewegungsabläufe gekennzeichnet sind (z. B. Morbus Parkinson, Chorea Huntington), auf Funktionsdefekte dieser Strukturen zurückgeführt. Der Thalamus wird häufig als Relaisstation des Informationsaustauschs zwischen anatomisch entfernten Arealen des Nervensystems aufgefasst. Basalganglien und Thalamus werden jedoch auch darüber hinausgehende Funktionen, z. B. zur Bereitstellung, Aufrechterhaltung und Auslenkung von Aufmerksamkeit bei der Bearbeitung kognitiver Aufgaben zugesprochen. In der vorliegenden Arbeit wurde mit elektrophysiologischen Methoden untersucht, ob auf der Ebene von Thalamus und Basalganglien kognitive Sprachleistungen, spezifisch der syntaktischen und semantischen Verarbeitung nachgewiesen werden können und inwieweit sich eventuell subkortikale von kortikaler Sprachverarbeitung unterscheidet.
Die Untersuchung spezieller Sprachfunktionen der Basalganglien und des Thalamus ist im Rahmen der operativen Behandlung bewegungsgestörter Patienten mit der sog. Tiefenhirnstimulation (DBS = engl. Deep Brain Stimulation) möglich. Hierbei werden Patienten mit Morbus Parkinson Stimulationselektroden in den Nucleus subthalamicus (STN) implantiert. Bei Patienten mit generalisierten Dystonien erfolgt die Implantation in den Globus pallidus internus (GPI) und bei Patienten mit essentiellem Tremor in den Nucleus ventralis intermedius (VIM). STN und GPI sind Kernareale der Basalganglien, der VIM ist Teil des motorischen Systems. Nach der Implantation besteht die Möglichkeit, direkt von diesen Elektroden elektroenzephalographische (EEG)-Signale abzuleiten und diese mit simultan abgeleiteten Oberflächen-EEG zu vergleichen.
In dieser Arbeit wurden DBS-Patienten aus allen genannten Gruppen in Bezug auf Sprachverständnisleistungen untersucht. Neben der Präsentation korrekter Sätze hörten die Patienten Sätze mit syntaktischen oder semantischen Fehlern. In verschiedenen Studien wurden an der Skalp-Oberfläche EKP-Komponenten (EKP = ereigniskorrelierte Potentiale) beschrieben, welche mit der Verarbeitung solcher Fehler in Verbindung gebracht werden. So verursachen syntaktische Phrasenstrukturverletzungen eine frühe links-anteriore Negativierung (ELAN). Dieser Komponente folgt eine späte Positivierung (P600), die mit Reanalyse und Reparaturmechanismen in Verbindung gebracht wird. Semantische Verletzungen evozieren eine breite Negativierung um 400ms (N400).
In den thalamischen Ableitungen wurden zwei zusätzliche syntaktische fehlerbezogene Komponenten gefunden, die (i) ~ 80ms nach der Skalp-ELAN und (ii) ~ 70ms vor der Skalp-P600 auftraten. Bei semantischen Verletzungen wurde im Thalamus ein fehlerbezogenes Potential nachgewiesen, welches weitgehend parallel mit dem am Skalp gefundenen Muster verläuft. Aus den Ergebnissen der vorliegenden Studie folgt, dass der Thalamus spezifische Sprachfunktionen erfüllt. Komponenten, die Sprachverarbeitungsprozesse reflektieren, konnten in den Basalganglienstrukturen STN und GPI nicht identifiziert werden.
Aufgrund der erhobenen Daten werden zwei getrennte Netzwerke für die Verarbeitung syntaktischer bzw. semantischer Fehler angenommen. In diesen Netzwerken scheint der Thalamus spezifische Aufgaben zu übernehmen. In einem ‚Syntaxnetzwerk’ kommunizieren frontale Hirnstrukturen unter Einbeziehung des Thalamus mit parietalen Hirnstrukturen. Dem Thalamus wurde eine Mediationsfunktion in der syntaktischen Reanalyse zugesprochen. In einem ‚Semantiknetzwerk’ waren keine eindeutig zuordenbaren Prozesse auf thalamischer Ebene nachweisbar. Es wurde eine unscharfe, jedoch aber spezifische Aktivierung des Thalamus über den gesamten Zeitraum der kortikalen semantischen Analyse gezeigt, welche als Integration verschiedener Analysemechanismen gewertet wurde.Since the beginning of empirical neuroscientific research language competence has been primary localized at the brain cortex. Improved functional neuroimaging techniques were able to localize lesions in structures which caused aphasic syndromes. These syndromes were particularly found after lesions of the basal ganglia and the thalamus These structures are located in the depth of the brain and communicate over widespread fiber connections with the cortex. Sensori-motor control functions are primarily assigned to the basal ganglia. Various diseases, which are characterized by disturbances of physiological courses of motion (e.g. Parkinson’s disease, Chorea Huntington) are attributed to function defects of these structures. The thalamus was originally understood as a simple relay station of information exchange between various cortical areas of the nervous system. However, additional functions were assigned to the basal ganglia and thalamus, e.g. maintenance and deflection of attention while processing of cognitive tasks. Within the present investigation thalamic and basal ganglia achievements in language processing were studied with electro-physiological methods to investigate differences between cortical and subcortical processes. The investigation of special language functions of the basal ganglia and the thalamus is possible in the context of the surgical treatment of movement-disordered patients with "Deep Brain Stimulation (DBS)". Stimulation electrodes have been implanted to patients with Parkinson’s disease into the subthalamic nucleus (STN), patients with generalized dystonia into the globus pallidus internus (GPi), and patients suffering from essential tremor into the ventral intermediate nucleus of the thalamus (VIM). STN and GPi are core areas of the basal ganglia, the VIM is part of the motor system. EEG-signals may be derived directly from these implanted electrodes and be compared to the simultaneously derived signals of a surface EEG. In this thesis DBS patients from all groups mentioned above were examined regarding language understanding achievements. The patients listened to sentences, which were either correct or syntactical or semantical incorrect. Different studies described scalp ERP components (ERP = event related potentials) which occurred after different types of errors in sentences. Thus, syntactic phrase structure violations cause an early left anterior negativity (ELAN). A late positivity (P600) follows this component and was hypothesized as a reflection of syntactical reanalysis and/or repair. Semantic violations evoke a broad negativity around 400ms (N400). In the thalamic EEG two additional syntactic components were identified, which were seen (i) ~ 80ms after the scalp ELAN and (ii) ~ 70ms before the scalp-P600. At thalamic level semantic violations caused a negativity, which parallels largely with the negativity found at the scalp. The results of this study suggest, that the thalamus fulfills specific language functions. In the basal ganglia structures (GPI and STN) no language specific components were found. Due to the collected data two separate networks are suggested for the processing of syntactic and/or semantic errors. In these networks the thalamus seems to fulfill specific tasks. In a "syntax network” frontal brain structures communicate with parietale brain structures via the thalamus. The function of the thalamus in this network is the mediation of the syntactic reanalysis. In a "semantic network” no clearly classified processes were proved at thalamic level, because of a similarity of thalamic and scalp signals. However, during the entire period of the cortical analysis activation of the thalamus was apparent. This activation was rated as integration of different analysis mechanisms.
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Ruffo, Mark. "The role of the corticothalamic projection in the primate motor thalamus /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10626.
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Cullen, Thomas. "The neuropathology of the prefrontal cortex and mediodorsal thalamus in schizophrenia." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427875.
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Prasad, Judy. "The nucleus reuniens of the midline thalamus: Anatomical and functional contributions." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123138.
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The thalamus is a heterogeneous brain region involved in sensory processes, movement and cognition. While there is much literature detailing the anatomy and electrophysiological properties of the midline thalamus, there is little data on the functional aspects of this region. There has recently been an interest in determining how the nucleus reuniens (NRe) of the midline thalamus is involved in cognitive processes, given its anatomical connections with both prefrontal cortex and hippocampus. While a few studies have focused on the NRe's involvement in memory (given its projections to the hippocampus), none have empirically examined whether the structure contributes to higher order, prefrontal-dependent functions. As such, there are two primary objectives of this dissertation. The first is to examine the anatomical organization of the NRe, and the second, to characterize the involvement of the NRe in higher order cognitive functions.Chapter 1 provides a review of the anatomical and functional literature describing the NRe. Traditional tracing studies have identified the NRe as a source of monosynaptic input to both the prefrontal cortex and hippocampus, but none have conclusively identified the NRe as the sole relay of prefrontal-hippocampal communication. In Chapter 2, we describe the use of a transynaptic tracer (pseudorabies virus, strain Bartha) to map the disynaptic connections from the prefrontal cortex to the hippocampus. We found that the NRe of the midline thalamus is one potential relay between the ventral prefrontal cortex and ventral hippocampus. As both of these regions have been implicated in response control and higher order cognitive behaviours, in Chapters 3 and 4 we tested rats with NRe lesions in behavioural tasks which assessed components of executive function. In Chapter 3, we measured the effects of rat NRe lesions in a test of inhibitory control and attention. Rats with NRe lesions displayed a high motivation to retrieve their food reward, and were able to accurately detect brief visual stimuli. In addition, lesions of the NRe resulted in transient impulsive behaviour while simultaneously decreasing compulsive responding. Given these behavioural changes, we further attempted to characterize the involvement of the NRe in prefrontal-dependent functions in Chapter 4. In a test of attention and working memory, we found that rats with NRe lesions were superior in their ability to attend to visual stimuli, as well as inhibit themselves from responding prior to the onset of the stimuli. However, the NRe-lesioned animals were initially unable to perform the working memory component of the task. This deficit was also seen during the acquisition of a spatial working memory task, but did not persist in subsequent sessions of testing. Rats with NRe lesions were faster and more accurately able to perform a discrimination task, and did not have difficulty with adapting to changes in the contingencies of the task. Unlike the previous experiments, the NRe lesion had no effect on behaviours assessed during a test of decision making.These findings are summarized in Chapter 5, in which the implications of the experimental data are discussed. While we have confirmed that the NRe is indeed a major thalamic link between the prefrontal cortex and hippocampus, we have also identified the subdivisions of the regions to which it connects. Furthermore, our data has extended the available behavioural literature regarding the function of the NRe, and how it is involved in higher order cognitive processes. We conclude that the NRe is clearly involved in a range of complex and prefrontal-dependent behaviours, proposing that this thalamic region is integral to executive function from both an anatomical and functional perspective.Le thalamus est une région hétérogène du cerveau impliquée dans les processus sensoriels, cognitifs ainsi que locomoteurs. Alors que la litterature détaillant l'anatomie et les propriétés électophysiologiques des noyaux thalamiques médians abonde, il existe peu de données décrivant son aspect fonctionnel. Considérant les connections anatomiques du noyau réuniens (NRe) du thamalus médian au cortex préfrontal et à l'hippocampe, de plus en plus de recherches se sont penchées sur son rôle dans les processus cognitifs. Alors que quelques études se sont penchées sur le rôle du NRe dans la mémoire (puisqu'il projette à l'hippocampe), aucune n'avait empiriquement examinée si le NRe contribuait aux fonctions cognitives supérieures dépendantes du cortex préfrontal (FCS). Ainsi, cette thèse se penchera sur deux aspects principaux du NRe. D'abord, l'organisation anatomique du NRe sera examinée, puis, son implication dans les FCS sera caractérisée. Le chapitre 1 fournira une révue de la littérature décrivant l'anatomie et les fonctions du NRe. Les études de traçage traditionnelles ont identifié le NRe comme fournissant une entrée monosynaptique à la fois au cortex préfontal et à l'hippocampe. Cependant, aucune étude n'a encore identifié le NRe comme un relais unique de la communication prefonto-hippocampal. Le chapitre 2 décrit l'utilisation d'un traceur transynaptique (l'herpèsvirus Bartha) afin de cartographier les connections disynpatiques partant du cortex préfontal à l'hippocampe. Les résultats présentés dans cette thèse montre que le NRe est un relais potentiel entre le cortex préfontal ventral et l'hippocampe ventral. Comme ces deux régions sont impliquées dans le contrôle de la réponse et les fonctions cognitives supérieures, les chapitre 3 et 4 traiteront des perfomances de rats ayant subis une lésion du NRe à des tâches comportementales évaluant les fonctions exécutives.Le chapitre 3 expose les effets d'une lésion du NRe chez le rat dans un test de contrôle de l'inhibition et d'attention. Les rats avec une lésion du NRe montrent une motivation accentuée pour obtenir la nourriture et démontre leur capacité à détecter précisément des stimuli visuels brefs. De plus, la lésion du NRe provoqua l'apparition de comportement impulsifs transitoires en plus de diminuer les réponses compulsives. Étant donné ces changements comportementaux, le rôle du NRe dans les FCS est caractérisé davantage au chapitre 4. Dans un test évaluant l'attention et la mémoire de travail, il a été démontré que les rats avec une lésion du NRe montraient une capacité supérieure à suivre les stimuli visuels ainsi qu'à inhiber leurs réponses avant l'apparition de ces stimuli. Cependant, les animaux ayant subi une lésion du NRe étaient initialement incapable de compléter la composante de la tâche impliquant la mémoire de travail. Ce déficit était aussi présent durant l'apprentissage de la tâche requérant la mémoire spatiale de travail mais a fini par s'estomper au fil des sessions subséquentes. Les rats avec une lésion du NRe étaient plus rapides à compléter une tâche de discrimination avec une plus grande précision et n'ont pas eu de difficulté à s'adapter aux changements de contingences de la tâche. Contrairement aux résultats précédents, la lésion du NRe n'a pas affecté le comportement tel qu'évalué durant une tâche de prise de décision.L'implication des ces résultats expérimentaux est discutée au chapitre 5. Il a été non seulement confirmé que le NRe est effectivement un lien majeur entre le cortex préfontal et l'hippocampe mais ces résultats identifient aussi avec une plus grande précision les régions où ils se connectent. De plus, ces données enrichissent la littérature comportementale sur le rôle du NRe et son implication dans les FCS. En conclusion, le NRe est clairement impliqué dans un éventail de FCS soutenant la thèse que cette région du thamalus est partie prenante des fonctions exécutives non seulement anatomiquement mais aussi fonctionnellement.
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Schuurman, Peter Richard. "Thalamic surgery for tremor." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/65876.
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Chan, Lai-yung, and 陳麗蓉. "Early blockade of glutamate receptors within the vestibular nucleus deters the maturation of thalamic neurons in the system for detectionof linear acceleration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44658825.
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Molnár, Zoltán. "Multiple mechanisms in the establishment of thalamocortical innervation." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:4e802e0b-6a11-4d92-9820-5697b70292c1.
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Gauriau, Caroline. "Etude comparative des projections issues de la couche I de la moelle épinière chez le rat : mise en évidence d'un nouveau relais thalamique de la nociception, le PoT." Paris 6, 2003. http://www.theses.fr/2003PA066134.
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BOUTTEN, BRIGITTE. "Demence thalamique par infarctus thalamique paramedian bilateral." Lille 2, 1988. http://www.theses.fr/1988LIL2M144.
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GRIFFIE, GILBERT. "Le langage au cours des hematomes thalamiques : 19 observations." Lille 2, 1988. http://www.theses.fr/1988LIL2M143.
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Cortés, Hernández Nelson. "Le rôle du noyau Pulvinar du thalamus dans la transmission de l'activité visuelle à travers le cortex." Paris 6, 2012. http://www.theses.fr/2012PA066375.
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Seules les voies cortico-corticales sont prises en compte d'habitude dans le flux d'informations à travers le cortex visuel. Cependant, les expériences et la théorie ont montré que ce mode de transmission posait de nombreux problèmes. Dans cette thèse, j'explore le rôle d'une voie alternative du flux d'information. La hiérarchie corticale visuelle est connecté au noyau Pulvinar du thalamus et cela fournit une seconde voie qui peut lier l'activité des différentes aires corticales. Le Pulvinar a des connexions longue portée qui lui confèrent un rôle de couplage global, conduisant à un raccourci efficace entre les aires corticales. Le but principal de ce travail est de montrer que cela permet une transmission quasi linéaire de l'entrée visuelle tout au long du cortex visuel. Deux modèles théoriques ont été implémentés pour analyser comment le Pulvinar améliore la transmission corticale. Le premier modèle est un réseau de neurones décrits par leur fréquence de décharge. Dans le second modèle, constitué de neurones << intègre-et-décharge >>, l'activité neuronale est décrite par des potentiels d'action. Les résultats de nos simulations montrent que les connexions cortico-corticales déterminent les champs récepteurs visuels à travers les niveaux hiérarchiques, le Pulvinar contrôle le gain de la propagation. De plus, alors que les connexions cortico-corticales sont responsables de la décorrélation du signal transmis à travers le cortex, les bouffées d'activité synchronisées du Pulvinar peuvent << réveiller >> le cortex.
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Blaszczyk, Lucie. "Etude des cellules astrocytaires et microgliales thalamiques dans un modèle de douleur neuropathique chez le rat." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0081/document.
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La douleur chronique est une pathologie invalidante de longue durée notamment caractériséepar trois symptômes : l’allodynie (un stimulus non douloureux est perçu comme douloureux),l’hyperalgésie (un stimulus douloureux est perçu comme encore plus douloureux) et desdouleurs ambulatoires. Quand cette douleur est due à une lésion ou une dysfonction du systèmenerveux on parle de douleur neuropathique. Chez les patients et les modèles animaux dedouleurs neuropathiques, les études ont montré que les neurones thalamiques étaienthyperexcitables. Les cellules gliales, astrocytes et microglies, sont des partenaires synaptiquesimpliqués dans la transmission et la plasticité synaptique et pourraient être impliqués dans cephénomène. En effet, ces cellules peuvent modifier leur phénotype lorsque le système nerveuxest affecté, elles sont réactives : leur morphologie est hypertrophiée, l’expression d’ARNm et deprotéines comme iba-1 (ionized binding-adaptor molecule 1) et CD11b/c (cluster ofdifferentiation 11b/c) pour les cellules microgliales et GFAP (glial fibrillary acidic protein) etS100β (S100 calcium binding protein β) pour les cellules astrocytaires est augmentée. Ellespeuvent également libérer des molécules pro-inflammatoires. Tout ceci pourrait générer ouamplifier l’hyperexcitabilité des neurones présents dans le thalamus.Mon travail de thèse a consisté en l’étude des astrocytes et de la microglie thalamique dans lemodèle de douleurs neuropathiques de ligature des nerfs spinaux L5-L6 du nerf sciatique (spinalnerve ligation, SNL). Les symptômes d’allodynie et d’hyperalgésie mécaniques ont étécaractérisés par le test des filaments de von Frey et les douleurs ambulatoires par le test dedistribution pondéral dynamique. L’expression des ARNm de marqueurs gliaux a été étudiée parune approche de qRT-PCR sur des prélèvements thalamiques et sur des noyaux thalamiquesobtenus par microdissection au laser. L’expression neurochimique des marqueurs iba-1,CD11b/c, Cathepsine S, GFAP et S100β a été étudié par immunohistofluorescence en quantifiantle nombre de cellules immunopositives et la surface occupée par les marqueurs. Toutes cesexpériences ont été réalisées à J14 et J28 après la chirurgie.A J14, les animaux SNL développent des symptômes d’allodynie et d’hyperalgésie mécaniqueainsi que des douleurs ambulatoires. Chez ces animaux, les cellules microgliales thalamiquesprésentent des signes de réactivité avec l’augmentation de l’expression des ARNm desmarqueurs CTSS et CX3CR1, le récepteur de la fractalkine, marqueurs connus pour leursimplications dans l’hyperexcitabilité neuronale spinale en conditions de douleursneuropathiques. De plus, l’expression neurochimique des marqueurs gliaux étudiés est diminuéece qui se traduit notamment par une diminution du nombre de cellules immunopositives pources marqueurs chez les animaux SNL. A J28, les symptômes douloureux sont maintenus. De plus,la réactivité microgliale décelée à J14 par qRT-PCR est toujours présente avec l’augmentation del’expression de l’ARNm codant pour la fractalkine (CX3CL1), partenaire de la voieCTSS/CX3CR1/CX3CL1. La diminution de l’expression neurochimique thalamique desmarqueurs gliaux chez les animaux SNL était transitoire et n’est plus présente à J28. Enrevanche, des signes de réactivité astrocytaire thalamique ont été mis en évidence chez lesanimaux SNL.Ainsi, ce travail dévoile une ambivalence au niveau des altérations de la glie thalamique dans cemodèle SNL: une diminution précoce de l’expression des marqueurs gliaux thalamiques suivied’une réactivité astrocytaire plus tardive concomitante à des signes de réactivité microgliale. Denombreuses expériences sont encore nécessaires pour appréhender l’impact de cetteambivalence gliale thalamique inédite dans un contexte de douleur neuropathiqueChronic pain is an incapacitating and long lasting pathology mainly characterized by threesymptoms: allodynia (a non painful stimulus is perceived as painful), hyperalgesia (a painfulstimulus is perceived as more painful) and ambulatory pains. When chronic pain is due to alesion or dysfunction of nervous system it is called neuropathic pain. In both patients and animalmodels of neuropathic pain, researchers found that thalamic neurons are hyperexcitable. Glialcells, astrocytes and microglia, are strong synaptic partners involved in synaptic transmissionand plasticity and therefore could be involved in this phenomenon. Indeed, these cells canmodify their phenotype when nervous system is damaged. They become reactive: theirmorphology is hypertrophied, mRNA and protein expression of iba-1 (ionized binding-adaptormolecule 1) and CD11b/c (cluster of differentiation 11b/c) for microglia and GFAP (glialfibrillary acidic protein) and S100β (S100 calcium binding protein β) for astrocytes is increased.They could also release pro-inflammatory molecules. All of these could contribute to generate oramplify the thalamic neuronal hyperexcitability.In my PhD work I studied thalamic astrocytes and microglia in a rat neuropathic pain model ofL5-L6 spinal nerves ligation (SNL). Mechanical allodynia and hyperalgesia were characterizedwith von Frey filament test and ambulatory pain with dynamic weight bearing apparatus. mRNAexpression of glial markers were studied with qRT-PCR technique on thalamic punches andlaser-microdissected nuclei. Neurochemical expressions of iba-1, CD11b/c, cathepsin S, GFAPand S100β markers were quantified using an immunohistofluorescence approach to count thenumber of immunopositive cells and surface stained by these markers. All these experimentswere done at D14 and D28 after surgery.At D14, SNL animals develop mechanical allodynia and hyperalgesia as well as ambulatory pain..For these animals, thalamic microglial cells showed signs of reactivity with the increase mRNAexpression of CTSS and CX3CR1, fractalkine receptor, well known markers involved in spinalneuronal hyperexcitability under neuropathic pain conditions. In addition, the number ofimmunopositive cells for the glial markers is decreased in SNL animals. At D28, the neuropathicpain symptoms are still present. Furthermore, thalamic microglial reactivity found at D14 withqRT-PCRm method is still present with the increased mRNA expression of fractalkine (CX3CL1),partner of CTSS/CX3CR1/CX3CL1 pathway. The decreased neurochemical expression of glialmarkers found at D14 was transient as I didn’t find this result at D28. However, thalamicastrocytic reactivity was found at D28 in SNL animals.So, this work reveal a new glial process at thalamic level in this SNL model of neuropathic pain :an early decreased expression of glial markers and then a later thalamic astrocytic reactivityconcomitant with signs of thalamic microglial reactivity. Numerous studies are required toexplore the role of such novel ambivalent glial alterations in the context of neuropathic pain
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Mudrová, Jaroslava. "Analýza vysokorychlostního železničního systému Thalys." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-4870.
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Railway history. High-speed railway systems. Characterization of high-speed railway service in France. European high-speed railway system. International high-speed railway system Thalys. History, statistics, technical information, company cooperation and positive measures to travellers.
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Arsenault, Dany. "Remodelage développemental des synapses lemniscales dans le noyau ventral postérieur du thalamus." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24267/24267.pdf.
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Xuereb, John H. "The thalamus in Alzheimer's and Parkinson's disease : a neuropathological and neurochemical study." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241453.
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Mouroux, Mireille. "Mise en évidence chez le rat, des capacités de contrôle du noyau parafasciculaire du thalamus sur deux structures des ganglions de la base : le noyau subthalamique et le globus pallidus." Paris 5, 1995. http://www.theses.fr/1995PA05P633.
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Borduas, Jean-Francois. "Modulation of Voltage-Gated Calcium Channels by Group II Metabotropic Glutamate Receptors in the Paraventricular Nucleus of the Thalamus." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19988.
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Compounds that interact with Group II metabotropic glutamate receptors (mGluRs) have antipsychotic effects in animal models. These drugs have also shown efficacy in the treatment of schizophrenia in humans. The mechanism of action is believed to arise from a reduction of glutamatergic transmission in limbic and forebrain regions commonly associated with this disorder. Previous anatomical tracer and lesion studies have revealed that neurons of the paraventricular nucleus of the thalamus (PVT) are an important source of the glutamatergic drive to these specific regions. However, the function of Group II mGluRs in the PVT remains to be determined. Whole-cell recordings from PVT neurons reveal that activation of these receptors has two interesting effects; it reduces calcium entry through voltage-gated calcium channels and it causes neurons to hyperpolarize. These two effects may contribute to affect the excitability of PVT neurons, an action that may underlie the effectiveness of Group II mGluR-activating compounds.
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Lau, Yau-pok. "Postnatal development of thalamic neurons in response to vertical movement /." View the Table of Contents & Abstract, 2007. http://sunzi.lib.hku.hk/hkuto/record/B3834810X.
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Loukavenko, Elena. "Recovery following anterior thalamic lesions." Thesis, University of Canterbury. Psychology, 2009. http://hdl.handle.net/10092/4151.
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Extensive neural connections between the anterior thalamic nuclei (ATN) and the hippocampal system may explain the overlapping amnesic syndromes associated with diencephalic and medial temporal lobe brain injury. Despite the debilitating nature of the diencephalic amnesia, treatments for this condition are lacking. In rats, lesions to the ATN or hippocampus generally produce similar memory deficits, which further implicate these structures in a single functional memory system. First evidence is presented here that seemingly permanent and robust spatial working memory deficits seen after lesions to the ATN in rats are ameliorated by environmental intervention and pharmacological treatment. Post-operative housing of ATN-lesioned rats for 30 days in enriched environment resulted in marked improvements in performance on the spatial working memory task in the cross-maze irrespective of whether rats were exposed to enrichment immediately after surgery or enrichment was delayed by 40 days post-surgery. Long-term beneficial effects of enrichment were also demonstrated. Behavioural improvements were observed when Cerebrolysin - a neurotrophic compound - was injected intraperitoneally for 30 days post-surgery. The combination of enrichment and Cerebrolysin treatment was more effective in inducing recovery on a delayed memory test in the cross-maze task. The influence of enrichment and Cerebrolysin on the neural changes produced by ATN lesions was examined utilising an immediate early gene marker c-fos. Replicating previous studies, ATN lesions produced marked hypoactivity in the retrosplenial cortex, but this effect was not reversed by either enrichment or Cerebrolysin. Unexpectedly, enrichment produced further hypoactivation in this region. Although lesion-induced deficits in a radial-arm maze spatial discrimination task were not improved by enrichment, a related study in our laboratory showed that spatial reference memory can also be improved by enrichment in ATN rats. The current research provides strong support for potential opportunities for therapeutic intervention in the human domain.
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劉友璞 and Yau-pok Lau. "Postnatal development of thalamic neurons in response to vertical movement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B45011369.
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Chaisuksunt, Vipavadee. "Differential expression of regeneration relevant molecules in neurons of adult rat brain after injury and the implantation of peripheral nerve grafts." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322006.
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