Статті в журналах: "Globus model"

1

Jiamahasap, Nachapong, and Sakgasem Ramingwong. "PREFERENCE MODEL FOR THAI LEASING COMPANIES." Globus An International Journal of Management & IT 10, no. 2 (July 30, 2019): 08. http://dx.doi.org/10.46360/globus.220191002.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Kanaskar, Nitin V., Umit Topaloglu, and Coskun Bayrak. "Globus security model for grid environment." ACM SIGSOFT Software Engineering Notes 30, no. 6 (November 2005): 1–9. http://dx.doi.org/10.1145/1102107.1102112.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Wilson, Janet A., I. J. Deary, and A. G. D. Maran. "Is Globus Hystericus?" British Journal of Psychiatry 153, no. 3 (September 1988): 335–39. http://dx.doi.org/10.1192/bjp.153.3.335.

Повний текст джерела

Анотація:

Forty-six patients, 9 male, 37 female, presenting to an ear, nose and throat department with a principal complaint of globus sensation were investigated by radiology, manometry, endoscopy and prolonged ambulatory pH monitoring to exclude a physical basis for their symptoms. Patients also underwent assessment by the Eysenck Personality Inventory (EPI) and General Health Questionnaire (GHQ). The only organic abnormalities detected were an abnormal degree of oesophageal acid exposure (seven patients) and oesophageal spasm (one patient). Female patients were neurotic introverts on EPI testing; males were stable ambiverts. High GHQ scores were present in 13 females (35%) and one male and there was a significant correlation between N scores (in the EPI) and GHQ scores. We propose that globus is a useful, single-symptom model for the study of conversion disorders.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Wang, Ying, An-Qi Chen, Yan Xue, Mei-Fang Liu, Cui Liu, Yun-Hai Liu, Yi-Peng Pan, Hui-Ling Diao, and Lei Chen. "Orexins alleviate motor deficits via increasing firing activity of pallidal neurons in a mouse model of Parkinson’s disease." American Journal of Physiology-Cell Physiology 317, no. 4 (October 1, 2019): C800—C812. http://dx.doi.org/10.1152/ajpcell.00125.2019.

Повний текст джерела

Анотація:

Orexin is a peptide neurotransmitter released in the globus pallidus. Morphological evidence reveals that both orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R) exist in the globus pallidus. Here we showed that bilateral microinjection of both orexin-A and orexin-B into the globus pallidus alleviated motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian mice. Further in vivo extracellular single-unit recording revealed that the basal spontaneous firing rate of the globus pallidus neurons in MPTP parkinsonian mice was slower than that of normal mice. Application of orexin-A or orexin-B significantly increased the spontaneous firing rate of pallidal neurons. The influx of Ca2+ through the L-type Ca2+ channel is the major mechanism involved in orexin-induced excitation in the globus pallidus. Orexin-A-induced increase in firing rate of pallidal neurons in MPTP parkinsonian mice was stronger than that of normal mice. Orexin-A exerted both electrophysiological and behavioral effects mainly via OX1R, and orexin-B exerted the effects via OX2R. Endogenous orexins modulated the excitability of globus pallidus neurons mainly through OX1R. The present behavioral and electrophysiological results suggest that orexins ameliorate parkinsonian motor deficits through increasing the spontaneous firing of globus pallidus neurons.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Berns, Gregory S., and Terrence J. Sejnowski. "A Computational Model of How the Basal Ganglia Produce Sequences." Journal of Cognitive Neuroscience 10, no. 1 (January 1998): 108–21. http://dx.doi.org/10.1162/089892998563815.

Повний текст джерела

Анотація:

We propose a systems-level computational model of the basal ganglia based closely on known anatomy and physiology. First, we assume that the thalamic targets, which relay ascending information to cortical action and planning areas, are tonically inhibited by the basal ganglia. Second, we assume that the output stage of the basal ganglia, the internal segment of the globus pallidus (GPi), selects a single action from several competing actions via lateral interactions. Third, we propose that a form of local working memory exists in the form of reciprocal connections between the external globus pallidus (GPe) and the subthalamic nucleus (STN). As a test of the model, the system was trained to learn a sequence of states that required the context of previous actions. The striatum, which was assumed to represent a conjunction of cortical states, directly selected the action in the GP during training. The STN-to-GP connection strengths were modified by an associative learning rule and came to encode the sequence after 20 to 40 iterations through the sequence. Subsequently, the system automatically reproduced the sequence when cued to the first action. The behavior of the model was found to be sensitive to the ratio of the striatal-nigral learning rate to the STN-GP learning rate. Additionally, the degree of striatal inhibition of the globus pallidus had a significant influence on both learning and the ability to select an action. Low learning rates, which would be hypothesized to reflect low levels of dopamine, as in Parkinson's disease, led to slow acquisition of contextual information. However, this could be partially offset by modeling a lesion of the globus pallidus that resulted in an increase in the gain of the STN units. The parameter sensitivity of the model is discussed within the framework of existing behavioral and lesion data.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Bulanin, V. V., G. S. Kurskiev, V. V. Solokha, A. Yu Yashin, and N. S. Zhiltsov. "The model of synchronization between internal reconnections and edge-localized modes." Plasma Physics and Controlled Fusion 63, no. 12 (November 16, 2021): 122001. http://dx.doi.org/10.1088/1361-6587/ac36a4.

Повний текст джерела

Анотація:

Abstract A new model for interaction between the internal reconnections caused by sawtooth and the edge-localized modes (ELM) was presented. The experimental evidence of the coupling between sawtooth crash and ELM events were observed in the Globus-M and Globus-M2 tokamaks. The numerical analysis of magnetic equilibrium showed that internal reconnections can induce the excess current density near the separatrix during the several hundreds of μs. The excess current destabilizes the peeling-ballooning (PB) instability. The PB stability analysis showed that the penetration depth of the induced current should be in the range of ψ norm = 0.8–0.95 to trigger the instability.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Ashby, F. Gregory, Shawn W. Ell, Vivian V. Valentin, and Michael B. Casale. "FROST: A Distributed Neurocomputational Model of Working Memory Maintenance." Journal of Cognitive Neuroscience 17, no. 11 (November 2005): 1728–43. http://dx.doi.org/10.1162/089892905774589271.

Повний текст джерела

Анотація:

Many studies suggest that the sustained activation underlying working memory (WM) maintenance is mediated by a distributed network that includes the prefrontal cortex and other structures (e.g., posterior parietal cortex, thalamus, globus pallidus, and the caudate nucleus). A computational model of WM, called FROST (short for FROntal-Striatal-Thalamic), is proposed in which the representation of items and spatial positions is encoded in the lateral prefrontal cortex. During delay intervals, activation in these prefrontal cells is sustained via parallel, prefrontal cortical-thalamic loops. Activation reverberates in these loops because prefrontal cortical excitation of the head of the caudate nucleus leads to disinhibition of the thalamus (via the globus pallidus). FROST successfully accounts for a wide variety of WM data, including single-cell recording data and human behavioral data.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Fujita, A., and S. Gotoh. "Analysis of the Domain Structures of MnZn Ferrites Using Globus' Model." Journal of the Magnetics Society of Japan 23, no. 4−2 (1999): 1409–12. http://dx.doi.org/10.3379/jmsjmag.23.1409.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Saltzman, Sid. "The Globus Model: Computer Simulation of Worldwide Political and Economic Developments." Conflict Management and Peace Science 11, no. 1 (February 1990): 97–99. http://dx.doi.org/10.1177/073889429001100106.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Mineev, A. B., E. N. Bondarchuk, A. A. Kavin, A. Yu Konin, I. Yu Rodin, V. N. Tanchuk, O. G. Filatov, et al. "ENGINEERING-PHYSICAL MODEL (GLOBSYS) FOR THE NEXT STEP OF THE GLOBUS-M SPHERICAL TOKAMAK PROGRAM MODEL DESCRIPTION AND COMPARISON WITH THE DATA OF DISCHARGE GLOBUS-M2." Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion 44, no. 3 (2021): 37–51. http://dx.doi.org/10.21517/0202-3822-2021-44-3-37-51.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Brotchie, Peter, Robert Iansek, and Malcolm Horne. "A neural network model of neural activity in the monkey globus pallidus." Neuroscience Letters 131, no. 1 (September 1991): 33–36. http://dx.doi.org/10.1016/0304-3940(91)90330-v.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Ku, Chung-Hsuan, Wen-Hung Huang, Ching-Wei Hsu, Yu-Chin Chen, Yi-Chou Hou, I.-Kuan Wang, Hsiang-Hsi Hong, Yen-Li Wang, Cheng-Hao Weng, and Tzung-Hai Yen. "Incidence Rate and Predictors of Globus Pallidus Necrosis after Charcoal Burning Suicide." International Journal of Environmental Research and Public Health 16, no. 22 (November 12, 2019): 4426. http://dx.doi.org/10.3390/ijerph16224426.

Повний текст джерела

Анотація:

Objective: This study examined predictors of globus pallidus necrosis as there was a paucity of literature of globus pallidus necrosis resulted from carbon monoxide poisoning after charcoal burning suicide. Methods: A total of 67 patients who had attempted charcoal burning suicide were recruited and stratified into two subgroups based on either presence (n = 40) or absence (n = 27) of globus pallidus necrosis. Demographic, clinical, laboratory, and radiographic data were obtained for cross-sectional analysis. All patients were followed to investigate the risks for mortality. Results: The patients aged 36.8 ± 11.1 years (67.2%) were male. Patients with globus pallidus necrosis were younger (p = 0.044) and had less hypertension (p = 0.015) than patients without globus pallidus necrosis. Furthermore, patients with globus pallidus necrosis suffered from severer medical complications, i.e., fever (p = 0.008), acute myocardial injury (p = 0.022), acute rhabdomyolysis (p = 0.022), and neuropsychiatric symptoms (p < 0.001) than patients without globus pallidus necrosis. Moreover, patients with globus pallidus necrosis received less hyperbaric oxygen therapy than without necrosis (p = 0.024). Two patients (3.0%) died on arrival. In a multivariable regression model, it was revealed that acute myocardial injury (odds ratio 4.6, confidence interval 1.1–18.9, p = 0.034) and neuropsychiatric symptoms (odds ratio 8.0, confidence interval 2.0–31.4, p = 0.003), decreased blood bicarbonate level (odds ratio 0.8, confidence interval 0.7–1.0, p = 0.032), and younger age (odds ratio 0.9, confidence interval 0.9–1.0, p = 0.038) were significant predictors for globus pallidus necrosis. Conclusion: Although patients who had attempted charcoal burning suicide had a low mortality rate (3.0%), globus pallidus necrosis was not uncommon (59.7%) in this population. Further studies are warranted.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Zhu, Bo, Luo Zhong, and Li Yang. "Research on Layered Resource Discovery Model in Grid." Advanced Materials Research 765-767 (September 2013): 955–58. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.955.

Повний текст джерела

Анотація:

Firstly, a Layered Resource Discovery Model (LRDM) was proposed in this paper according to different resource type in grid. Then all components of LRDM were analyzed and designed in detail with resource discovery module in Globus Tookit4, mainly including resource description, resource information organization and resource request processing. Finally, the model was implemented and proved to have the characteristics high discovery efficiency and scalability because of combining the advantages of both centralized and distributed mechanisms.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Ligot, Noémie, Pierre Krystkowiak, Clémence Simonin, Serge Goldman, Philippe Peigneux, John Van Naemen, Michel Monclus, et al. "External Globus Pallidus Stimulation Modulates Brain Connectivity in Huntington's Disease." Journal of Cerebral Blood Flow & Metabolism 31, no. 1 (October 20, 2010): 41–46. http://dx.doi.org/10.1038/jcbfm.2010.186.

Повний текст джерела

Анотація:

Positron emission tomography with O-15-labeled water was used to study at rest the neurophysiological effects of bilateral external globus pallidus (GPe) deep brain stimulation in patients with Huntington's disease (HD). Five patients were compared with a control group in the on and off states of the stimulator. External globus pallidus stimulation decreased neuronal activity and modulated cerebral connectivity within the basal ganglia-thalamocortical circuitry, the sensorimotor, and the default-mode networks. These data indicate that GPe stimulation modulates functional integration in HD patients in accordance with the basal ganglia-thalamocortical circuit model.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Bi, Yuanhong, Quansheng Liu, Jingyi Zhao, and Wuritu Yang. "Dynamical Analyses on Beta Oscillations in a STN-GPE-GPI Model of Parkinson’s Disease." Complexity 2020 (September 9, 2020): 1–9. http://dx.doi.org/10.1155/2020/4376279.

Повний текст джерела

Анотація:

Exploring the behaviors of beta oscillations in the basal ganglia is helpful to understand the mechanism of Parkinson’s disease. Studies have shown that the external and internal segments (GPe, GPi) of the globus pallidus receive different intensities of signals from the striatum in Parkinson’s disease and play different roles in the production of beta oscillations, but the relevant mechanism still remains unclear. Based on a model of the subthalamic nucleus (STN) and globus pallidus (GP), we propose an extended STN-GPe-GPi model and analyze the dynamical behaviors of beta oscillations in this model. The stability condition is obtained through theoretical analyses, and the generation of beta oscillations by the inputs from the cortex and striatum is further considered. The influence of some parameters related to GPi on its firing rate oscillations is discussed. The results obtained in this paper are expected to play a guiding role in the medical treatment of Parkinson’s disease.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Wang, Xiaomin, Ying Yu, Fang Han, and Qingyun Wang. "Beta-band bursting activity in computational model of heterogeneous external globus pallidus circuits." Communications in Nonlinear Science and Numerical Simulation 110 (July 2022): 106388. http://dx.doi.org/10.1016/j.cnsns.2022.106388.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Rossi, Jessica, Francesco Cavallieri, Giada Giovannini, Francesca Benuzzi, Daniela Ballotta, Anna Elisabetta Vaudano, Francesca Ferrara, et al. "Can Disruption of Basal Ganglia-Thalamocortical Circuit in Wilson Disease Be Associated with Juvenile Myoclonic Epilepsy Phenotype?" Brain Sciences 12, no. 5 (April 26, 2022): 553. http://dx.doi.org/10.3390/brainsci12050553.

Повний текст джерела

Анотація:

In this paper, we describe the multimodal MRI findings in a patient with Wilson disease and a seizure disorder, characterized by an electroclinical picture resembling juvenile myoclonic epilepsy. The brain structural MRI showed a deposition of ferromagnetic materials in the basal ganglia, with marked hypointensities in T2-weighted images of globus pallidus internus bilaterally. A resting-state fMRI study revealed increased functional connectivity in the patient, compared to control subjects, in the following networks: (1) between the primary motor cortex and several cortical regions, including the secondary somatosensory cortex and (2) between the globus pallidus and the thalamo-frontal network. These findings suggest that globus pallidus alterations, due to metal accumulation, can lead to a reduction in the normal globus pallidus inhibitory tone on the thalamo-(motor)-cortical pathway. This, in turn, can result in hyperconnectivity in the motor cortex circuitry, leading to myoclonus and tonic-clonic seizures. We suppose that, in this patient, Wilson disease generated a ‘lesion model’ of myoclonic epilepsy.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Rossi, Jessica, Francesco Cavallieri, Giada Giovannini, Francesca Benuzzi, Daniela Ballotta, Anna Elisabetta Vaudano, Francesca Ferrara, et al. "Can Disruption of Basal Ganglia-Thalamocortical Circuit in Wilson Disease Be Associated with Juvenile Myoclonic Epilepsy Phenotype?" Brain Sciences 12, no. 5 (April 26, 2022): 553. http://dx.doi.org/10.3390/brainsci12050553.

Повний текст джерела

Анотація:

In this paper, we describe the multimodal MRI findings in a patient with Wilson disease and a seizure disorder, characterized by an electroclinical picture resembling juvenile myoclonic epilepsy. The brain structural MRI showed a deposition of ferromagnetic materials in the basal ganglia, with marked hypointensities in T2-weighted images of globus pallidus internus bilaterally. A resting-state fMRI study revealed increased functional connectivity in the patient, compared to control subjects, in the following networks: (1) between the primary motor cortex and several cortical regions, including the secondary somatosensory cortex and (2) between the globus pallidus and the thalamo-frontal network. These findings suggest that globus pallidus alterations, due to metal accumulation, can lead to a reduction in the normal globus pallidus inhibitory tone on the thalamo-(motor)-cortical pathway. This, in turn, can result in hyperconnectivity in the motor cortex circuitry, leading to myoclonus and tonic-clonic seizures. We suppose that, in this patient, Wilson disease generated a ‘lesion model’ of myoclonic epilepsy.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Fujita, Tomohiro, and Katsunori Kitano. "Spike synchrony modulated by membrane properties in a network model of globus pallidus externus." Neuroscience Research 65 (January 2009): S169. http://dx.doi.org/10.1016/j.neures.2009.09.886.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Балаченков, И. М., Ю. В. Петров, В. К. Гусев, Н. Н. Бахарев, В. И. Варфоломеев, В. В. Дьяченко, А. Н. Коновалов та ін. "Обнаружение высокочастотных альфвеновских колебаний в омических разрядах сферического токамака Глобус-М2". Письма в журнал технической физики 47, № 12 (2021): 17. http://dx.doi.org/10.21883/pjtf.2021.12.51061.18730.

Повний текст джерела

Анотація:

In Globus-M2 ohmic discharges with low density, by means of Mirnov coils array, magnetic field oscillations with frequencies in 1 MHz range were detected. Frequency range of these oscillations significantly exceed the range of TAE and RSAE frequencies, which were previously observed on Globus-M and Globus-M2 tokamaks, and their amplitude, contrary, turned out to be up to an order of magnitude lower. It was found that high frequency oscillations are interrelated with suprathermal electron fraction. At the same time the observed instability seems to have Alfvenic nature, since its frequency correlates well with Alfven frequency scaling. It was also found that magnetic perturbation always forms standing wave with predominantly low toroidal wavenumbers, including n = 0 structure, which makes gap (e.g. TAE) mode excitation impossible. Frequency chirping during single bursts with δω ~ √t is consistent with hole-clump model predictions.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Caiola, Michael, and Mark H. Holmes. "Model and Analysis for the Onset of Parkinsonian Firing Patterns in a Simplified Basal Ganglia." International Journal of Neural Systems 29, no. 01 (January 10, 2019): 1850021. http://dx.doi.org/10.1142/s0129065718500211.

Повний текст джерела

Анотація:

Parkinson’s disease (PD) is a degenerative neurological disease that disrupts the movement cycle in the basal ganglia. As the disease progresses, dopamine depletion leads to changes to how the basal ganglia functions as well as the appearance of abnormal beta oscillations. There is much debate on just exactly how these connection strengths change and just how the oscillations emerge. One leading hypothesis claims that the oscillations develop in the globus pallidus external, subthalamic nucleus, and globus pallidus internal loop. We introduce a mathematical model that calculates the average firing rates of this loop while still accounting for the larger closed loop of the entire basal ganglia system. This model is constructed such that physiologically realistic results can be obtained while not sacrificing the use of analytic methods. Because of this, it is possible to determine how the change in the connection strengths can drive the necessary changes in firing rates seen in recordings and account for the generation of trademark beta oscillations of PD without relying on highly specific time delays, stochastic approaches, or numerical approximations. Additionally, we find that the entire cortico-basal ganglia-thalamo-cortical loop is essential for abnormal oscillations to originate.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

NAHVI, ALIREZA, FARIBA BAHRAMI, and SAMIRA HEMMATI. "INVESTIGATING DIFFERENT TARGETS IN DEEP BRAIN STIMULATION ON PARKINSON'S DISEASE USING A MEAN-FIELD MODEL OF THE BASAL GANGLIA-THALAMOCORTICAL SYSTEM." Journal of Mechanics in Medicine and Biology 12, no. 02 (April 2012): 1240004. http://dx.doi.org/10.1142/s0219519412400040.

Повний текст джерела

Анотація:

In this paper, we investigated effects of deep brain stimulation (DBS) on Parkinson's disease (PD) when different target sites in the basal ganglia are stimulated. The targets which are investigated are subthalamic nucleus (STN), globus pallidus interna (GPi), and globus pallidus externa (GPe). For this purpose we used a computational model of the basal ganglia-thalamocortical system (BGTCS) with parameters calculated for mean field. This model is able to reproduce both the normal and Parkinsonian activities of basal ganglia, thalamus and cortex in a unified structure. In the present study, we used a mean-field model of the BGTCS, allowing a more complete framework to simulate DBS and to interpret its effects in the BGTCS. Our results suggest that DBS in the STN and GPe could restore the thalamus relay activity, while DBS in the GPi could inhibit it. Our results are compatible with the experimental and the clinical outcomes about the effects of DBS of different targets.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Gangadhar, Garipelli, Denny Joseph, and V. Srinivasa Chakravarthy. "Understanding Parkinsonian Handwriting Through a Computational Model of Basal Ganglia." Neural Computation 20, no. 10 (October 2008): 2491–525. http://dx.doi.org/10.1162/neco.2008.03-07-498.

Повний текст джерела

Анотація:

Handwriting in Parkinson's disease (PD) is typically characterized by micrographia, jagged line contour, and unusual fluctuations in pen tip velocity. Although PD handwriting features have been used for diagnostics, they are not based on a signaling model of basal ganglia (BG). In this letter, we present a computational model of handwriting generation that highlights the role of BG. When PD conditions like reduced dopamine and altered dynamics of the subthalamic nucleus and globus pallidus externa subsystems are simulated, the handwriting produced by the model manifested characteristic PD handwriting distortions like micrographia and velocity fluctuations. Our approach to PD modeling is in tune with the perspective that PD is a dynamic disease.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Ozen, Ilknur, Karsten Ruscher, Robert Nilsson, Johanna Flygt, Fredrik Clausen, and Niklas Marklund. "Interleukin-1 Beta Neutralization Attenuates Traumatic Brain Injury-Induced Microglia Activation and Neuronal Changes in the Globus Pallidus." International Journal of Molecular Sciences 21, no. 2 (January 8, 2020): 387. http://dx.doi.org/10.3390/ijms21020387.

Повний текст джерела

Анотація:

Traumatic brain injury (TBI) increases the risk of delayed neurodegenerative processes, including Parkinson’s disease (PD). Interleukin-1beta (IL-1β), a key pro-inflammatory cytokine, may promote secondary injury development after TBI. Conversely, neutralizing IL-1β was found to improve functional recovery following experimental TBI. However, the mechanisms underlying the behavioral improvements observed by IL-1β neutralization are still poorly understood. The present study investigated the role of IL-1β on the microglia response and neuronal changes in the globus pallidus in response to diffuse TBI. Mice were subjected to sham injury or the central fluid percussion injury (cFPI) (a model of traumatic axonal injury), and were randomly administered an IL-1β neutralizing or a control antibody at 30 min post-injury. The animals were analyzed at 2, 7, or 14 days post-injury. When compared to controls, mice subjected to cFPI TBI had increased microglia activation and dopaminergic innervation in the globus pallidus, and a decreased number of parvalbumin (PV) positive interneurons in the globus pallidus. Neutralization of IL-1β attenuated the microglia activation, prevented the loss of PV+ interneurons and normalized dopaminergic fiber density in the globus pallidus of brain-injured animals. These findings argue for an important role for neuro-inflammation in the PD-like pathology observed in TBI.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Vasques, Xavier, Laura Cif, Olivier Hess, Sophie Gavarini, Gerard Mennessier, and Philippe Coubes. "Stereotactic model of the electrical distribution within the internal globus pallidus during deep brain stimulation." Journal of Computational Neuroscience 26, no. 1 (June 17, 2008): 109–18. http://dx.doi.org/10.1007/s10827-008-0101-y.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Dudkovskaia, A. V., M. I. Patrov, V. K. Gusev, E. O. Kiselev, and G. S. Kurskiev. "NTM threshold island width measurements on Globus-M based on the Fitzpatrick heat transport model." Journal of Physics: Conference Series 1400 (November 2019): 077039. http://dx.doi.org/10.1088/1742-6596/1400/7/077039.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Zhao, Jing-Yi, Quan-Sheng Liu, Yuan-Hong Bi, and Zhuo-Qin Yang. "Analyses of conditions for generating beta oscillations in the Cortex–Subthalamic Nucleus–Globus Pallidus model." Modern Physics Letters B 34, no. 13 (February 28, 2020): 2050134. http://dx.doi.org/10.1142/s0217984920501341.

Повний текст джерела

Анотація:

Analyzing the conditions for generating beta oscillation in basal ganglia plays a key role in understanding the mechanism of Parkinson’s disease (PD). In this paper, we consider a Cortex–STN–GPe model, which consists of the external segment of globus pallidus (GPe), subthalamic nucleus (STN) and cortex including excitatory and inhibitory neurons. We obtain the stability boundary conditions for the model through theoretical analyses, and discuss the influence of two inputs to cortex and GPe on oscillations by numerical simulation. Our results reveal that the model can oscillate for large connection weight between STN and GPe, much larger input to the cortex, and most input values to the GPe. Furthermore, the effects of parameters in the cortical circuit on the amplitude and frequency of the beta oscillation are analyzed. We show that larger delay and larger firing rate of excitatory and inhibitory neurons in the cortex make the model oscillate easily. We hope that our results will be helpful for further understanding the mechanisms of beta oscillations in the treatment of Parkinson’s disease and may apply to some studies of neural oscillations.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Johnson, Matthew D., and Cameron C. McIntyre. "Quantifying the Neural Elements Activated and Inhibited by Globus Pallidus Deep Brain Stimulation." Journal of Neurophysiology 100, no. 5 (November 2008): 2549–63. http://dx.doi.org/10.1152/jn.90372.2008.

Повний текст джерела

Анотація:

Deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) is an effective therapy option for controlling the motor symptoms of medication-refractory Parkinson's disease and dystonia. Despite the clinical successes of GPi DBS, the precise therapeutic mechanisms are unclear and questions remain on the optimal electrode placement and stimulation parameter selection strategies. In this study, we developed a three-dimensional computational model of GPi-DBS in nonhuman primates to investigate how membrane channel dynamics, synaptic inputs, and axonal collateralization contribute to the neural responses generated during stimulation. We focused our analysis on three general neural elements that surround GPi-DBS electrodes: GPi somatodendritic segments, GPi efferent axons, and globus pallidus pars externa (GPe) fibers of passage. During high-frequency electrical stimulation (136 Hz), somatic activity in the GPi showed interpulse excitatory phases at 1–3 and 4–5.5 ms. When including stimulation-induced GABAA and AMPA receptor dynamics into the model, the somatic firing patterns continued to be entrained to the stimulation, but the overall firing rate was reduced (78.7 to 25.0 Hz, P < 0.001). In contrast, axonal output from GPi neurons remained largely time-locked to each pulse of the stimulation train. Similar entrainment was also observed in GPe efferents, a majority of which have been shown to project through GPi en route to the subthalamic nucleus. The models suggest that pallidal DBS may have broader network effects than previously realized and the modes of therapy may depend on the relative proportion of GPi and/or GPe efferents that are directly affected by the stimulation.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Loonen, Anton J. M., and Svetlana A. Ivanova. "Consider Role of Glutamatergic Habenula-projecting Globus Pallidus in OCD." Pharmacopsychiatry 52, no. 04 (February 4, 2019): 203–4. http://dx.doi.org/10.1055/a-0835-6447.

Повний текст джерела

Анотація:

AbstractRecently, in a review article in this journal, Vlček and colleagues described the putative role played by the glutamatergic system in obsessive-compulsive disorder (OCD) and how this might explain the effects of certain treatments. They describe a neuroanatomical model, which includes a specific role of the amygdala-hippocampus complex (AHC) and would complete the classic cortico-striatal-thalamo-cortical (CSTC) mechanism of OCD. The role of the AHC can perhaps be better understood when considering its ancient relationship to the rest of the forebrain of mammals. This leads to distinguishing between primary (lamprey-like), secondary (amphibian-like) and tertiary (mammal-like) parts of the forebrain including amygdaloid, ventral extrapyramidal and dorsal extrapyramidal systems, respectively. A specific role in OCD may be played by the habenula-projecting part of the pallidum, which evaluated the result of behaviour in human’s earliest vertebrate ancestors. The addition of these primary relationship to the authors’ description could be fruitful when planning the future research, as suggested by them.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Xie, Jinlu, Tao Li, Tingting He, Rong Xu, Xianshan Zhang, Xuenan Wang, and Xiwen Geng. "Deep brain stimulation on the external segment of the globus pallidus improves the electrical activity of internal segment of globus pallidus in a rat model of Parkinson's disease." Brain Research 1797 (December 2022): 148115. http://dx.doi.org/10.1016/j.brainres.2022.148115.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

D’Angelo, Vincenza, Mauro Giorgi, Emanuela Paldino, Silvia Cardarelli, Francesca R. Fusco, Ilaria Saverioni, Roberto Sorge, et al. "A2A Receptor Dysregulation in Dystonia DYT1 Knock-Out Mice." International Journal of Molecular Sciences 22, no. 5 (March 7, 2021): 2691. http://dx.doi.org/10.3390/ijms22052691.

Повний текст джерела

Анотація:

We aimed to investigate A2A receptors in the basal ganglia of a DYT1 mouse model of dystonia. A2A was studied in control Tor1a+/+ and Tor1a+/− knock-out mice. A2A expression was assessed by anti-A2A antibody immunofluorescence and Western blotting. The co-localization of A2A was studied in striatal cholinergic interneurons identified by anti-choline-acetyltransferase (ChAT) antibody. A2A mRNA and cyclic adenosine monophosphate (cAMP) contents were also assessed. In Tor1a+/+, Western blotting detected an A2A 45 kDa band, which was stronger in the striatum and the globus pallidus than in the entopeduncular nucleus. Moreover, in Tor1a+/+, immunofluorescence showed A2A roundish aggregates, 0.3–0.4 μm in diameter, denser in the neuropil of the striatum and the globus pallidus than in the entopeduncular nucleus. In Tor1a+/−, A2A Western blotting expression and immunofluorescence aggregates appeared either increased in the striatum and the globus pallidus, or reduced in the entopeduncular nucleus. Moreover, in Tor1a+/−, A2A aggregates appeared increased in number on ChAT positive interneurons compared to Tor1a+/+. Finally, in Tor1a+/−, an increased content of cAMP signal was detected in the striatum, while significant levels of A2A mRNA were neo-expressed in the globus pallidus. In Tor1a+/−, opposite changes of A2A receptors’ expression in the striatal-pallidal complex and the entopeduncular nucleus suggest that the pathophysiology of dystonia is critically dependent on a composite functional imbalance of the indirect over the direct pathway in basal ganglia.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Chang, H. T., W. K. Rumbeiha, J. S. Patterson, B. Puschner, and A. P. Knight. "Toxic Equine Parkinsonism: An Immunohistochemical Study of 10 Horses With Nigropallidal Encephalomalacia." Veterinary Pathology 49, no. 2 (April 28, 2011): 398–402. http://dx.doi.org/10.1177/0300985811406885.

Повний текст джерела

Анотація:

Chronic ingestion of yellow star thistle ( Centaurea solstitialis) or Russian knapweed ( Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease. Results confirm that the NPE lesions are located within the substantia nigra pars reticulata, sparing the cell bodies of the dopaminergic neurons in the substantia nigra pars compacta, and in the rostral portion of the globus pallidus, with partial disruption of dopaminergic (tyrosine hydroxylase–positive) fibers passing through the globus pallidus. No abnormal cytoplasmic inclusions like the Lewy bodies of human Parkinson disease were seen in these NPE brains. These findings indicate that equine NPE may serve as a large animal model of environmentally acquired toxic parkinsonism, with clinical phenotype directly attributable to lesions in globus pallidus and substantia nigra pars reticulata rather than to the destruction of dopaminergic neurons.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Dorval, Alan D., Gary S. Russo, Takao Hashimoto, Weidong Xu, Warren M. Grill, and Jerrold L. Vitek. "Deep Brain Stimulation Reduces Neuronal Entropy in the MPTP-Primate Model of Parkinson's Disease." Journal of Neurophysiology 100, no. 5 (November 2008): 2807–18. http://dx.doi.org/10.1152/jn.90763.2008.

Повний текст джерела

Анотація:

High-frequency stimulation (HFS) of the subthalamic nucleus (STN) or internal segment of the globus pallidus is a clinically successful treatment for the motor symptoms of Parkinson's disease. However, the mechanisms by which HFS alleviates these symptoms are not understood. Whereas initial studies focused on HFS-induced changes in neuronal firing rates, recent studies suggest that changes in patterns of neuronal activity may correlate with symptom alleviation. We hypothesized that effective STN HFS reduces the disorder of neuronal firing patterns in the basal ganglia thalamic circuit, minimizing the pathological activity associated with parkinsonism. Stimulating leads were implanted in the STN of two rhesus monkeys rendered parkinsonian by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Action potentials were recorded from neurons of the internal and external globus pallidus and the motor thalamus (ventralis anterior, ventralis lateralis pars oralis, and ventralis posterior lateralis pars oralis) during HFS that reduced motor symptoms and during clinically ineffective low-frequency stimulation (LFS). Firing pattern entropy was calculated from the recorded spike times to quantify the disorder of the neuronal activity. The firing pattern entropy of neurons within each region of the pallidum and motor thalamus decreased in response to HFS ( n ≥ 18 and P ≤ 0.02 in each region), whereas firing rate changes were specific to pallidal neurons only. In response to LFS, firing rates were unchanged, but firing pattern entropy increased throughout the circuit ( n ≥ 24 and P ≤ 10−4 in each region). These data suggest that the clinical effectiveness of HFS is correlated with, and potentially mediated by, a regularization of the pattern of neuronal activity throughout the basal ganglia thalamic circuit.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Hu, Bing, Zhizhi Wang, Minbo Xu, Luyao Zhu, and Dingjiang Wang. "The therapeutic mechanism of epilepsy seizures in different target areas: Research on a theoretical model." Technology and Health Care 29 (March 25, 2021): 455–61. http://dx.doi.org/10.3233/thc-218043.

Повний текст джерела

Анотація:

BACKGROUND: The selection of optimal target areas in the surgical treatment of epilepsy is always a difficult problem in medicine. OBJECTIVE: We employed a theoretical calculation model to explore the control mechanism of seizures by an external voltage stimulus acting in different nerve nuclei. METHODS: Theoretical analysis and numerical simulation were combined. RESULTS: The globus pallidus, excitatory pyramidal neurons, striatal D1 neurons, thalamic reticular nucleus and specific relay nuclei were selected, we analyzed that the electrical stimulation has different effects in these target areas. CONCLUSIONS: The data selected were reasonable in study, the results may give a theoretical support for similar studies in clinical.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Bartlett, L. E., and I. Mendez. "Dopaminergic Reinnervation of the Globus Pallidus by Fetal Nigral Grafts in the Rodent Model of Parkinson's Disease." Cell Transplantation 14, no. 2-3 (February 2005): 119–27. http://dx.doi.org/10.3727/000000005783983241.

Повний текст джерела

Анотація:

The current neural transplantation strategy for Parkinson's disease (PD) involves the dopaminergic reinnervation of the striatum (STR). Although up to 85% reinnervation of the STR has been attained by neural transplantation, functional recovery in animal models and transplanted patients is incomplete. This limitation may be due to an incomplete restoration of the dopaminergic input to other basal ganglia structures such as the external segment of the globus pallidus (GPe, homologue of the rodent GP), which normally receives dopaminergic input from the substantia nigra (SN). As part of our investigation into a multiple grafting strategy for PD, we have explored the effects of dopaminergic grafts in the GP of rodents with unilateral 6-hydroxydopamine (6-OHDA) lesions. In this experiment, lesioned rats received either 300,000 fetal ventral mesencephalic (FVM) cells or a sham injection into the GP. Functional assessment consisted of rotational behavior at 3 and 6 weeks posttransplantation. A fluorogold tracer study was conducted to rule out any behavioral improvement due to striatal outgrowth of the GP graft. Sections were stained for glial fibrillary acidic protein (GFAP) to assess the degree of trauma in the GP by the graft in comparison to the sham injection. Immunohistochemistry for tyrosine hydroxylase (TH) was performed after transplantation to assess graft survival. Animals with GP grafts demonstrated a significant improvement in rotational behavior at 3 and 6 weeks posttransplantation (p < 0.05) while sham control animals did not improve. All animals receiving FVM cells showed TH-immunoreactive grafts in the GP posttransplantation. TH-positive neurons in the GP showed no double labeling with an intrastriatal injection of fluorogold, indicating that behavioral improvement was not due to striatal innervation by the GP graft. These observations suggest that functional recovery was the result of dopaminergic reinnervation of the GP and that this nucleus may be a potential target for neural transplantation in clinical PD.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Suryanarayana, Shreyas M., Jeanette Hellgren Kotaleski, Sten Grillner, and Kevin N. Gurney. "Roles for globus pallidus externa revealed in a computational model of action selection in the basal ganglia." Neural Networks 109 (January 2019): 113–36. http://dx.doi.org/10.1016/j.neunet.2018.10.003.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Fujita, Tomohiro, Tomoki Fukai, and Katsunori Kitano. "Influences of membrane properties on phase response curve and synchronization stability in a model globus pallidus neuron." Journal of Computational Neuroscience 32, no. 3 (October 13, 2011): 539–53. http://dx.doi.org/10.1007/s10827-011-0368-2.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Nakao, N., M. Ogura, K. Nakai, and T. Itakura. "Embryonic striatal grafts restore neuronal activity of the globus pallidus in a rodent model of Huntington's disease." Neuroscience 88, no. 2 (January 1999): 469–77. http://dx.doi.org/10.1016/s0306-4522(98)00197-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Vasques, Xavier, Laura Cif, Olivier Hess, Sophie Gavarini, Gerard Mennessier, and Philippe Coubes. "Prognostic value of globus pallidus internus volume in primary dystonia treated by deep brain stimulation." Journal of Neurosurgery 110, no. 2 (February 2009): 220–28. http://dx.doi.org/10.3171/2008.3.17433.

Повний текст джерела

Анотація:

Object Given that improvement is variable from one patient to another, the authors analyzed the impact of globus pallidus internus (GPi) volume on the result of deep brain stimulation (DBS) by comparing highly and less improved patients with primary dystonodyskinetic syndromes. Methods A stereotactic model was developed to visualize and quantify the relationship between the isofield lines generated by the DBS lead and GPi target. The model was used in 30 right-handed selected patients with primary dystonodyskinetic syndromes who had been treated using bilateral stimulation of the sensorimotor GPi. Ten healthy control individuals were also included in the study. First, the authors compared the GPi volumes between patients and healthy controls. Second, the stimulated GPi volumes, that is, the intersection between the volume of each isofield value and the GPi volumes, were compared between less improved and highly improved patients. Results Improvement in the Burke-Fahn-Marsden Dystonia Rating Scale's motor score was rated > 90% in 20 patients (97 ± 4.6%) and < 60% in 10 patients (56.9 ± 6%). The mean volume of the right (461.8 ± 81.8 mm3) and left (406.6 ± 113.2 mm3) GPi in patients showing less response to DBS was significantly smaller than the GPi volume of patients who responded well (right 539.9 ± 86.6 mm3, left 510.6 ± 88.7 mm3) and healthy controls (right 557.8 ± 109.1 mm3, left 525.1 ± 40.8 mm3). Conclusions On the left side, the mean stimulated volumes (isofield line range 0.2–1 V/mm) were significantly larger in highly improved than in less improved patients. In this model, the threshold for functional effect was calculated at 0.2 V/mm.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Szubin, Roman. "Образ мирового человека в романе Алексея Иванова „Географ глобус пропил"". Kultury Wschodniosłowiańskie - Oblicza i Dialog, № 7 (31 липня 2018): 175–86. http://dx.doi.org/10.14746/kw.2017.7.14.

Повний текст джерела

Анотація:

The article is devoted to a research of archaic models in Alexei Ivanov’s creativity. On the material of the novel entitled Geographer has spent on drink the globe(Geograf globus propil) the images and motifs of rescue, as well as the archaic image of rescue described in Vardan Hayrapetyan’s hermeneutics are revealed. In the center of a research is the main character, another example of an archetype of the Russian literature — the little person. In particular, his uncommon abilities to understand, to decode and interpret are emphasized. The attention is also paid to the hermeneutical model of the communication consisting of three instances: speaking (nature), the listener (who is willfully understanding the pupil) and the interpreter (the teacher) whose efforts supplement the anthropomorphous model of unity — the all-man, the one-man (mirovoj chelovek).

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Ryu, Sang Baek, Eun Kyung Bae, Jinhyung Kim, Yong Sup Hwang, Changkyun Im, Jin Woo Chang, Hyung-Cheul Shin, and Kyung Hwan Kim. "Neuronal Responses in the Globus Pallidus during Subthalamic Nucleus Electrical Stimulation in Normal and Parkinson's Disease Model Rats." Korean Journal of Physiology & Pharmacology 17, no. 4 (2013): 299. http://dx.doi.org/10.4196/kjpp.2013.17.4.299.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Tomiyama, M., A. Arai, G. Zhu, T. Kimura, T. Kawarabayashi, M. Okada, and M. Shoji. "2.406 Enhanced GABA release in the medial globus pallidus in a rat model of L-DOPA-induced dyskinesia." Parkinsonism & Related Disorders 13 (January 2007): S129. http://dx.doi.org/10.1016/s1353-8020(08)70726-0.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Cleary, Daniel R., Ahmed M. Raslan, Jonathan E. Rubin, Diaa Bahgat, Ashwin Viswanathan, Mary M. Heinricher, and Kim J. Burchiel. "Deep brain stimulation entrains local neuronal firing in human globus pallidus internus." Journal of Neurophysiology 109, no. 4 (February 15, 2013): 978–87. http://dx.doi.org/10.1152/jn.00420.2012.

Повний текст джерела

Анотація:

Deep brain stimulation (DBS) in the internal segment of the globus pallidus (GPi) relieves the motor symptoms of Parkinson's disease, yet the mechanism of action remains uncertain. To address the question of how therapeutic stimulation changes neuronal firing in the human brain, we studied the effects of GPi stimulation on local neurons in unanesthetized patients. Eleven patients with idiopathic Parkinson's disease consented to participate in neuronal recordings during stimulator implantation surgery. A recording microelectrode and a DBS macroelectrode were advanced through the GPi in parallel until a single neuron was isolated. After a baseline period, stimulation was initiated with varying voltages and different stimulation sites. The intra-operative stimulation parameters (1–8 V, 88–180 Hz, 0.1-ms pulses) were comparable with the postoperative DBS settings. Stimulation in the GPi did not silence local neuronal activity uniformly, but instead loosely entrained firing and decreased net activity in a voltage-dependent fashion. Most neurons had decreased activity during stimulation, although some increased or did not change firing rate. Thirty-three of 45 neurons displayed complex patterns of entrainment during stimulation, and burst-firing was decreased consistently after stimulation. Recorded spike trains from patients were used as input into a model of a thalamocortical relay neuron. Only spike trains that occurred during therapeutically relevant voltages significantly reduced transmission error, an effect attributable to changes in firing patterns. These data indicate that DBS in the human GPi does not silence neuronal activity, but instead disrupts the pathological firing patterns through loose entrainment of neuronal activity.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Hazell, Alan S., Louise Normandin, Bich Nguyen, and Greg Kennedy. "Upregulation of ‘peripheral-type’ benzodiazepine receptors in the globus pallidus in a sub-acute rat model of manganese neurotoxicity." Neuroscience Letters 349, no. 1 (September 2003): 13–16. http://dx.doi.org/10.1016/s0304-3940(03)00649-9.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Ayalon, Liat, Ravid Doron, Ina Weiner, and Daphna Joel. "Amelioration of behavioral deficits in a rat model of Huntington's disease by an excitotoxic lesion to the globus pallidus." Experimental Neurology 186, no. 1 (March 2004): 46–58. http://dx.doi.org/10.1016/s0014-4886(03)00312-1.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Edgerton, J. R., and D. Jaeger. "Dendritic Sodium Channels Promote Active Decorrelation and Reduce Phase Locking to Parkinsonian Input Oscillations in Model Globus Pallidus Neurons." Journal of Neuroscience 31, no. 30 (July 27, 2011): 10919–36. http://dx.doi.org/10.1523/jneurosci.6062-10.2011.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Brass, S. D., R. HB Benedict, B. Weinstock-Guttman, F. Munschauer, and R. Bakshi. "Cognitive impairment is associated with subcortical magnetic resonance imaging grey matter T2 hypointensity in multiple sclerosis." Multiple Sclerosis Journal 12, no. 4 (August 2006): 437–44. http://dx.doi.org/10.1191/135248506ms1301oa.

Повний текст джерела

Анотація:

Grey matter hypointensity on T2-weighted magnetic resonance imaging (MRI) scans, suggesting iron deposition, has been described in multiple sclerosis (MS) and is related to physical disability, disease course and brain atrophy. We tested the hypothesis that subcortical grey matter T2 hypointensity is related to cognitive impairment after adjusting for the effect of MRI lesion and atrophy measures. We studied 33 patients with MS and 14 healthy controls. Normalized T2 signal intensity in the caudate, putamen, globus pallidus and thalamus, total brain T1-hypointense lesion volume (T1LV), fluid-attenuated inversion-recovery-hyperintense lesion volume (FLLV) and brain parenchymal fraction (BPF) were obtained quantitatively. A neuropsychological composite score (NCS) encompassed new learning, attention, working memory, spatial processing and executive function. In each of the regions of interest, the normalized T2 intensity was lower in the MS versus control group (all P <0.001). Regression modelling tested the relative association between all MRI variables and NCS. Globus pallidus T2 hypointensity was the only variable selected in the final model ( R2 = 0.301, P = 0.007). Pearson correlations between MRI and NCS were T1LV: r = -0.319; FLLV: r = -0.347; BPF: r = 0.374; T2 hypointensity of the caudate: r = 0.305; globus pallidus: r = 0.395; putamen: r = 0.321; and thalamus: r = 0.265. Basal ganglia T2 hypointensity and BPF demonstrated the strongest associations with cognitive impairment on individual cognitive subtests. Subcortical grey matter T2 hypointensity is related to cognitive impairment in MS, supporting the clinical relevance of T2 hypointensity as a biological marker of MS tissue damage. These data implicate a role for basal ganglia iron deposition in neuropsychological dysfunction.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

SRIDHARAN, D., P. S. PRASHANTH, and V. S. CHAKRAVARTHY. "THE ROLE OF THE BASAL GANGLIA IN EXPLORATION IN A NEURAL MODEL BASED ON REINFORCEMENT LEARNING." International Journal of Neural Systems 16, no. 02 (April 2006): 111–24. http://dx.doi.org/10.1142/s0129065706000548.

Повний текст джерела

Анотація:

We present a computational model of basal ganglia as a key player in exploratory behavior. The model describes exploration of a virtual rat in a simulated water pool experiment. The virtual rat is trained using a reward-based or reinforcement learning paradigm which requires units with stochastic behavior for exploration of the system's state space. We model the Subthalamic Nucleus-Globus Pallidus externa (STN-GPe) segment of the basal ganglia as a pair of neuronal layers with oscillatory dynamics, exhibiting a variety of dynamic regimes such as chaos, traveling waves and clustering. Invoking the property of chaotic systems to explore state-space, we suggest that the complex exploratory dynamics of STN-GPe system in conjunction with dopamine-based reward signaling from the Substantia Nigra pars compacta (SNc) present the two key ingredients of a reinforcement learning system.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

KWAK, JAESIK, and YOON SUP LEE. "A COMPUTATIONAL GRID SYSTEM FOR QUANTUM CHEMICAL CALCULATIONS TESTED IN A MODELING OF THE GE(001) SURFACE." Journal of Theoretical and Computational Chemistry 04, no. 01 (March 2005): 289–303. http://dx.doi.org/10.1142/s0219633605001490.

Повний текст джерела

Анотація:

A computational Grid system with the simple architecture was constructed based on Globus and the concept of web application for the quantum chemical calculation. The computational Grid provides interfaces to a web-based input module and several molecular orbital calculation packages. Some aspects of the cluster modeling of the Ge (001) surface were tested on the constructed Grid. A number of conditions and parameters of the cluster model can be easily varied on the Grid, enabling concurrent testing of multiple choices of the model possible. These models were benchmarked on the Grid system. After that, the potential energy surface of the acetylene molecule moving over the model Ge (001) surface was scanned, in an effort to understand the adsorption reaction. Each point of the potential energy surface was calculated on the distributed node of the Grid system. These results demonstrate that the concept of high throughput computing can be successfully adapted to computational chemistry with a computational Grid. The result of modeling for the Ge surface itself is also described and could be of some interest.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Hwang, Yong Sup, Insop Shim, Bom Bee Lee, and Jin Woo Chang. "Effect of subthalamic nucleus lesions in a 6-hydroxydopamine–induced rat parkinsonian model: behavioral and biochemical studies." Journal of Neurosurgery 105, no. 2 (August 2006): 284–87. http://dx.doi.org/10.3171/jns.2006.105.2.284.

Повний текст джерела

Анотація:

Object The purpose of this study was to determine whether subthalamic nucleus (STN) ablation caused by kainic acid can restore dopaminergic neurotransmission and improve motor deficits in a 6-hydroxydopamine (6-OHDA)–induced hemiparkinsonian model. Methods The authors investigated behavioral changes in rats displaying parkinsonian symptoms (6-OHDA–lesioned rats) after an STN lesion was created using kainic acid. They also measured levels of dopamine and its metabolites following tissue dissection. The results of this study showed that STN ablation led to behavioral improvement in parkinsonian motor deficits. Increased levels of dopamine were also observed in the striatum and globus pallidus externus (GPE). Conclusions The results indicate that creation of an STN lesion in this hemiparkinsonian rat model may counteract some of the neurochemical changes within the striatum and GPE caused by the 6-OHDA, and influence striatal dopaminergic metabolism.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Globus model"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями