Artículos de revistas: "Whole-brain map"

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Brittin, Christopher A., Steven J. Cook, David H. Hall, Scott W. Emmons y Netta Cohen. "A multi-scale brain map derived from whole-brain volumetric reconstructions". Nature 591, n.º 7848 (24 de febrero de 2021): 105–10. http://dx.doi.org/10.1038/s41586-021-03284-x.

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Lee, Dongha y Hae-Jeong Park. "A populational connection map for the whole brain white matter". IBRO Reports 6 (septiembre de 2019): S153. http://dx.doi.org/10.1016/j.ibror.2019.07.486.

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Bernat, James L. "THE BIOPHILOSOPHICAL BASIS OF WHOLE-BRAIN DEATH". Social Philosophy and Policy 19, n.º 2 (julio de 2002): 324–42. http://dx.doi.org/10.1017/s0265052502192132.

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Notwithstanding these wise pronouncements, my project here is to characterize the biological phenomenon of death of the higher animal species, such as vertebrates. My claim is that the formulation of “whole-brain death” provides the most congruent map for our correct understanding of the concept of death. This essay builds upon the foundation my colleagues and I have laid since 1981 to characterize the concept of death and refine when this event occurs. Although our society's well-accepted program of multiple organ procurement for transplantation requires the organ donor first to be dead, the concept of brain death is not merely a social contrivance to permit us to obtain the benefits of organ procurement. Rather, the concept of whole-brain death stands independently as the most accurate biological representation of the demise of the human organism.

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Shi, Yuhang, S. Johanna Vannesjo, Karla L. Miller y Stuart Clare. "Template-based field map prediction for rapid whole brain B0 shimming". Magnetic Resonance in Medicine 80, n.º 1 (28 de noviembre de 2017): 171–80. http://dx.doi.org/10.1002/mrm.27020.

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Jung, Youjin, Raymond P. Viviano, Sanneke van Rooden, Jeroen van der Grond, Serge A. R. B. Rombouts y Jessica S. Damoiseaux. "White Matter Hyperintensities and Apolipoprotein E Affect the Association Between Mean Arterial Pressure and Objective and Subjective Cognitive Functioning in Older Adults". Journal of Alzheimer's Disease 84, n.º 3 (23 de noviembre de 2021): 1337–50. http://dx.doi.org/10.3233/jad-210695.

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Background: White matter hyperintensities (WMH) show a robust relationship with arterial pressure as well as objective and subjective cognitive functioning. In addition, APOE ɛ4 carriership may influence how arterial pressure affects cognitive functioning. Objective: To determine the role of region-specific WMH burden and APOE ɛ4 carriership on the relationship between mean arterial pressure (MAP) and cognitive function as well as subjective cognitive decline (SCD). Methods: The sample consisted of 87 cognitively unimpaired middle-aged to older adults aged 50–85. We measured WMH volume for the whole brain, anterior thalamic radiation (ATR), forceps minor, and superior longitudinal fasciculus (SLF). We examined whether WMH burden mediated the relationship between MAP and cognition (i.e., TMT-A score for processing speed; Stroop performance for executive function) as well as SCD (i.e., Frequency of Forgetting (FoF)), and whether APOE ɛ4 carriership moderated that mediation. Results: WMH burden within SLF mediated the effect of MAP on Stroop performance. Both whole brain and ATR WMH burden mediated the effect of MAP on FoF score. In the MAP–WMH–Stroop relationship, the mediation effect of SLF WMH and the effect of MAP on SLF WMH were significant only in APOE ɛ4 carriers. In the MAP–WMH–FoF relationship, the effect of MAP on whole brain WMH burden was significant only in ɛ4 carriers. Conclusion: WMH burden and APOE genotype explain the link between blood pressure and cognitive function and may enable a more accurate assessment of the effect of high blood pressure on cognitive decline and risk for dementia.

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Morone, Flaviano, Kevin Roth, Byungjoon Min, H. Eugene Stanley y Hernán A. Makse. "Model of brain activation predicts the neural collective influence map of the brain". Proceedings of the National Academy of Sciences 114, n.º 15 (28 de marzo de 2017): 3849–54. http://dx.doi.org/10.1073/pnas.1620808114.

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Efficient complex systems have a modular structure, but modularity does not guarantee robustness, because efficiency also requires an ingenious interplay of the interacting modular components. The human brain is the elemental paradigm of an efficient robust modular system interconnected as a network of networks (NoN). Understanding the emergence of robustness in such modular architectures from the interconnections of its parts is a longstanding challenge that has concerned many scientists. Current models of dependencies in NoN inspired by the power grid express interactions among modules with fragile couplings that amplify even small shocks, thus preventing functionality. Therefore, we introduce a model of NoN to shape the pattern of brain activations to form a modular environment that is robust. The model predicts the map of neural collective influencers (NCIs) in the brain, through the optimization of the influence of the minimal set of essential nodes responsible for broadcasting information to the whole-brain NoN. Our results suggest intervention protocols to control brain activity by targeting influential neural nodes predicted by network theory.

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Deleo, Francesco, Seok-Jun Hong, Fatemeh Fadaie, Benoit Caldairou, Sidney Krystal, Neda Bernasconi y Andrea Bernasconi. "Whole-brain multimodal MRI phenotyping of periventricular nodular heterotopia". Neurology 95, n.º 17 (14 de agosto de 2020): e2418-e2426. http://dx.doi.org/10.1212/wnl.0000000000010648.

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ObjectiveTo test the hypothesis that in periventricular nodular heterotopia (PVNH) structure and function of cortical areas overlying the heterotopic gray matter are preferentially affected.MethodsWe studied a group of 40 patients with PVNH and normal-appearing cortex and compared their quantitative MRI markers of brain development, structure, and function to those of 43 age- and sex-matched healthy controls. Inspired by models of neocortical development suggesting that neuronal migration follows a curvilinear path to preserve topologic correspondence between the outer ventricular zone and the cortical surface, we computationally defined the overlying cortex using the Laplace equation and generated synthetic streamlines that link the ventricles, where nodules are located, and the neocortex.ResultsWe found multilobar cortical thickening encompassing prefrontal, latero-basal temporal, and temporoparietal cortices largely corresponding with the PVNH group-averaged map of the overlying cortex, the latter colocalized with areas of abnormal function, as defined by resting-state fMRI. Patients also presented hippocampal functional hyperconnectivity and malrotation, the latter positively correlating with neocortical maldevelopment indexed by increased folding complexity of the parahippocampus. In clusters of thickness and curvature findings, there were no significant differences between unilateral and bilateral PVNH; contrasting brain-wide metrics between cohorts was also unrevealing. There was no relationship between imaging markers and disease duration except for positive correlation with functional anomalies.ConclusionOur quantitative image analysis demonstrates widespread structural and functional alterations in PVNH with differential interaction with the overlying cortex and the hippocampus. Right hemispheric predominance may be explained by an early insult, likely genetically determined, on brain morphogenesis.

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Tao, Jingshan, Yong Cai, Yisheng Dai, Yingdi Xie, Hailing Liu y Xiaojin Zang. "Value of 4D CT Angiography Combined with Whole Brain CT Perfusion Imaging Feature Analysis under Deep Learning in Imaging Examination of Acute Ischemic Stroke". Computational Intelligence and Neuroscience 2022 (13 de junio de 2022): 1–9. http://dx.doi.org/10.1155/2022/2286413.

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This study was aimed at investigating the application of deep learning 4D computed tomography angiography (CTA) combined with whole brain CT perfusion (CTP) imaging in acute ischemic stroke (AIS). A total of 46 patients with ischemic stroke were selected from the hospital as the research objects. Image quality was analyzed after the 4D CTA images were obtained by perfusion imaging. The results showed that whole brain perfusion imaging based on FCN can achieve automatic segmentation. FCN segmentation results took a short time, an average of 2-3 seconds, and the Dice similarity coefficient (DSC) and mean absolute distance (MAD) were lower than those of other algorithms. FCN segmentation distance was 17.87. The parameters of the central area, the peripheral area, and the mirror area of the perfusion map were compared, and the mean transit time (MTT) and time to peak (TTP) of the lesion were prolonged compared with the mirror area. Moreover, the peripheral CBV was increased, and the differences between the parameters were significant ( P < 0.05 ). In conclusion, using the deep learning FCN network, 4D CTA combined with whole brain CTP imaging technology can effectively analyze the perfusion state and achieve clinically personalized treatment.

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Jehl, Markus, Ekaterina Mikhaylova, Valerie Treyer, Marlena Hofbauer, Martin Hüllner, Philipp A. Kaufmann, Alfred Buck et al. "Attenuation Correction Using Template PET Registration for Brain PET: A Proof-of-Concept Study". Journal of Imaging 9, n.º 1 (21 de diciembre de 2022): 2. http://dx.doi.org/10.3390/jimaging9010002.

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NeuroLF is a dedicated brain PET system with an octagonal prism shape housed in a scanner head that can be positioned around a patient’s head. Because it does not have MR or CT capabilities, attenuation correction based on an estimation of the attenuation map is a crucial feature. In this article, we demonstrate this method on [18F]FDG PET brain scans performed with a low-resolution proof of concept prototype of NeuroLF called BPET. We perform an affine registration of a template PET scan to the uncorrected emission image, and then apply the resulting transform to the corresponding template attenuation map. Using a whole-body PET/CT system as reference, we quantitively show that this method yields comparable image quality (0.893 average correlation to reference scan) to using the reference µ-map as obtained from the CT scan of the imaged patient (0.908 average correlation). We conclude from this initial study that attenuation correction using template registration instead of a patient CT delivers similar results and is an option for patients undergoing brain PET.

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Yang, Hsiao T. y Kevin J. Cummings. "Brain stem serotonin protects blood pressure in neonatal rats exposed to episodic anoxia". Journal of Applied Physiology 115, n.º 12 (15 de diciembre de 2013): 1733–41. http://dx.doi.org/10.1152/japplphysiol.00970.2013.

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In neonatal rodents, a loss of brain stem serotonin [5-hydroxytryptamine (5-HT)] in utero or at birth compromises anoxia-induced gasping and the recovery of heart rate (HR) and breathing with reoxygenation (i.e., autoresuscitation). How mean arterial pressure (MAP) is influenced after an acute loss of brain stem 5-HT content is unknown. We hypothesized that a loss of 5-HT for ∼1 day would compromise MAP during episodic anoxia. We injected 6-fluorotryptophan (20 mg/kg ip) into rat pups (postnatal days 9–10 or 11–13, n = 22 treated, 24 control), causing a ∼70% loss of brain stem 5-HT. Pups were exposed to a maximum of 15 anoxic episodes, separated by 5 min of room air to allow autoresuscitation. In younger pups, we measured breathing frequency and tidal volume using “head-out” plethysmography and HR from the electrocardiogram. In older pups, we used whole body plethysmography to detect gasping, while monitoring MAP. Gasp latency and the time required for respiratory, HR, and MAP recovery following each episode were determined. Despite normal gasp latency, breathing frequency and a larger tidal volume ( P < 0.001), 5-HT-deficient pups survived one-half the number of episodes as controls ( P < 0.001). The anoxia-induced decrease in MAP experienced by 5-HT-deficient pups was double that of controls ( P = 0.017), despite the same drop in HR ( P = 0.48). MAP recovery was delayed ∼10 s by 5-HT deficiency ( P = 0.001). Our data suggest a loss of brain stem 5-HT leads to a pronounced, premature loss of MAP in response to episodic anoxia. These data may help explain why some sudden infant death syndrome cases die from what appears to be cardiovascular collapse during apparent severe hypoxia.

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Nadig, Ajay, Jakob Seidlitz, Cassidy L. McDermott, Siyuan Liu, Richard Bethlehem, Tyler M. Moore, Travis T. Mallard et al. "Morphological integration of the human brain across adolescence and adulthood". Proceedings of the National Academy of Sciences 118, n.º 14 (2 de abril de 2021): e2023860118. http://dx.doi.org/10.1073/pnas.2023860118.

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Brain structural covariance norms capture the coordination of neurodevelopmental programs between different brain regions. We develop and apply anatomical imbalance mapping (AIM), a method to measure and model individual deviations from these norms, to provide a lifespan map of morphological integration in the human cortex. In cross-sectional and longitudinal data, analysis of whole-brain average anatomical imbalance reveals a reproducible tightening of structural covariance by age 25 y, which loosens after the seventh decade of life. Anatomical imbalance change in development and in aging is greatest in the association cortex and least in the sensorimotor cortex. Finally, we show that interindividual variation in whole-brain average anatomical imbalance is positively correlated with a marker of human prenatal stress (birthweight disparity between monozygotic twins) and negatively correlated with general cognitive ability. This work provides methods and empirical insights to advance our understanding of coordinated anatomical organization of the human brain and its interindividual variation.

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Wild, J. M., H. Reinke y S. M. Farabaugh. "A non-thalamic pathway contributes to a whole body map in the brain of the budgerigar". Brain Research 755, n.º 1 (abril de 1997): 137–41. http://dx.doi.org/10.1016/s0006-8993(97)00026-7.

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Kaboodvand, Neda, Martijn P. van den Heuvel y Peter Fransson. "Adaptive frequency-based modeling of whole-brain oscillations: Predicting regional vulnerability and hazardousness rates". Network Neuroscience 3, n.º 4 (enero de 2019): 1094–120. http://dx.doi.org/10.1162/netn_a_00104.

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Whole-brain computational modeling based on structural connectivity has shown great promise in successfully simulating fMRI BOLD signals with temporal coactivation patterns that are highly similar to empirical functional connectivity patterns during resting state. Importantly, previous studies have shown that spontaneous fluctuations in coactivation patterns of distributed brain regions have an inherent dynamic nature with regard to the frequency spectrum of intrinsic brain oscillations. In this modeling study, we introduced frequency dynamics into a system of coupled oscillators, where each oscillator represents the local mean-field model of a brain region. We first showed that the collective behavior of interacting oscillators reproduces previously shown features of brain dynamics. Second, we examined the effect of simulated lesions in gray matter by applying an in silico perturbation protocol to the brain model. We present a new approach to map the effects of vulnerability in brain networks and introduce a measure of regional hazardousness based on mapping of the degree of divergence in a feature space.

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Li, Xiangning, Bin Yu, Qingtao Sun, Yalun Zhang, Miao Ren, Xiaoyan Zhang, Anan Li et al. "Generation of a whole-brain atlas for the cholinergic system and mesoscopic projectome analysis of basal forebrain cholinergic neurons". Proceedings of the National Academy of Sciences 115, n.º 2 (19 de diciembre de 2017): 415–20. http://dx.doi.org/10.1073/pnas.1703601115.

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The cholinergic system in the brain plays crucial roles in regulating sensory and motor functions as well as cognitive behaviors by modulating neuronal activity. Understanding the organization of the cholinergic system requires a complete map of cholinergic neurons and their axon arborizations throughout the entire brain at the level of single neurons. Here, we report a comprehensive whole-brain atlas of the cholinergic system originating from various cortical and subcortical regions of the mouse brain. Using genetically labeled cholinergic neurons together with whole-brain reconstruction of optical images at 2-μm resolution, we obtained quantification of the number and soma volume of cholinergic neurons in 22 brain areas. Furthermore, by reconstructing the complete axonal arbors of fluorescently labeled single neurons from a subregion of the basal forebrain at 1-μm resolution, we found that their projections to the forebrain and midbrain showed neuronal subgroups with distinct projection specificity and diverse arbor distribution within the same projection area. These results suggest the existence of distinct subtypes of cholinergic neurons that serve different regulatory functions in the brain and illustrate the usefulness of complete reconstruction of neuronal distribution and axon projections at the mesoscopic level.

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Ruggieri, Serena, Fulvia Fanelli, Letizia Castelli, Nikolaos Petsas, Laura De Giglio y Luca Prosperini. "Lesion symptom map of cognitive–postural interference in multiple sclerosis". Multiple Sclerosis Journal 24, n.º 5 (24 de marzo de 2017): 653–62. http://dx.doi.org/10.1177/1352458517701313.

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Objective: To investigate the disease-altered structure–function relationship underlying the cognitive–postural interference (CPI) phenomenon in multiple sclerosis (MS). Methods: We measured postural sway of 96 patients and 48 sex-/age-matched healthy controls by force platform in quiet standing (single-task (ST)) while performing the Stroop test (dual-task (DT)) to estimate the dual-task cost (DTC) of balance. In patient group, binary T2 and T1 lesion masks and their corresponding lesion volumes were obtained from magnetic resonance imaging (MRI) of brain. Normalized brain volume (NBV) was also estimated by SIENAX. Correlations between DTC and lesion location were determined by voxel-based lesion symptom mapping (VLSM) analyses. Results: Patients had greater DTC than controls ( p < 0.001). Among whole brain MRI metrics, only T1 lesion volume correlated with DTC ( r = −0.27; p < 0.01). However, VLSM analysis did not reveal any association with DTC using T1 lesion masks. By contrast, we found clusters of T2 lesions in distinct anatomical regions (anterior and superior corona radiata, bilaterally) to be correlated with DTC ( p < 0.01 false discovery rate (FDR)-corrected). A multivariable stepwise regression model confirmed findings from VLSM analysis. NBV did not contribute to fit the model. Conclusion: Our findings suggest that the CPI phenomenon in MS can be explained by disconnection along specific areas implicated in task-switching abilities and divided attention.

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Kirstein, Marina y Rolien Kunz. "A Whole Brain® learning approach to an undergraduate auditing initiative – an exploratory study". Meditari Accountancy Research 24, n.º 4 (3 de octubre de 2016): 527–44. http://dx.doi.org/10.1108/medar-02-2014-0029.

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Purpose Individual students have different learning styles, and lecturers can no longer afford to ignore this. Lecturers have a responsibility to accommodate students’ different learning styles by including learning style flexibility in the offered learning opportunities. The purpose of this study is to map a teaching case study against the Herrmann Whole Brain® model to determine whether learning style flexibility has been incorporated in the teaching case study. Design/methodology/approach A teaching case study was developed and delivered as part of an undergraduate level course at a South African residential university. The case study’s primary intention was to illustrate the practical evaluation of general controls in an information technology environment. The teaching case study was analysed in terms of the Herrmann Whole Brain® model to determine whether learning style flexibility had been accommodated in the learning opportunity. Findings Based on an analysis of the teaching case study against the Herrmann Whole Brain® model, it is evident that the teaching case study incorporated activities that addressed all four quadrants of the Whole Brain® model. It can therefore be concluded that the learning opportunity incorporated learning style flexibility. Originality/value This paper contributes to the literature in accounting education by focusing on learning style flexibility specifically using the Herrmann Whole Brain® model, as it appears that limited examples of the use of this model in accounting education have yet been published. Although this paper discusses the use of an auditing case study, the results may be of interest to lecturers in other subject areas across the academic spectrum.

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Fu, Jia-Yu, Xiao-Dan Yu, Yi Zhu, Shi-Ze Xie, Meng-Yu Tang, Bin Yu y Xiao-Ming Li. "Whole-Brain Map of Long-Range Monosynaptic Inputs to Different Cell Types in the Amygdala of the Mouse". Neuroscience Bulletin 36, n.º 11 (20 de julio de 2020): 1381–94. http://dx.doi.org/10.1007/s12264-020-00545-z.

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AbstractThe amygdala, which is involved in various behaviors and emotions, is reported to connect with the whole brain. However, the long-range inputs of distinct cell types have not yet been defined. Here, we used a retrograde trans-synaptic rabies virus to generate a whole-brain map of inputs to the main cell types in the mouse amygdala. We identified 37 individual regions that projected to neurons expressing vesicular glutamate transporter 2, 78 regions to parvalbumin-expressing neurons, 104 regions to neurons expressing protein kinase C-δ, and 89 regions to somatostatin-expressing neurons. The amygdala received massive projections from the isocortex and striatum. Several nuclei, such as the caudate-putamen and the CA1 field of the hippocampus, exhibited input preferences to different cell types in the amygdala. Notably, we identified several novel input areas, including the substantia innominata and zona incerta. These findings provide anatomical evidence to help understand the precise connections and diverse functions of the amygdala.

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Sun, Qingtao, Xiangning Li, Miao Ren, Mengting Zhao, Qiuyuan Zhong, Yuqi Ren, Pan Luo et al. "A whole-brain map of long-range inputs to GABAergic interneurons in the mouse medial prefrontal cortex". Nature Neuroscience 22, n.º 8 (8 de julio de 2019): 1357–70. http://dx.doi.org/10.1038/s41593-019-0429-9.

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Duan, Zhuonan, Anan Li, Hui Gong y Xiangning Li. "A Whole-brain Map of Long-range Inputs to GABAergic Interneurons in the Mouse Caudal Forelimb Area". Neuroscience Bulletin 36, n.º 5 (19 de enero de 2020): 493–505. http://dx.doi.org/10.1007/s12264-019-00458-6.

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Jonas, Jacques, Corentin Jacques, Joan Liu-Shuang, Hélène Brissart, Sophie Colnat-Coulbois, Louis Maillard y Bruno Rossion. "A face-selective ventral occipito-temporal map of the human brain with intracerebral potentials". Proceedings of the National Academy of Sciences 113, n.º 28 (27 de junio de 2016): E4088—E4097. http://dx.doi.org/10.1073/pnas.1522033113.

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Human neuroimaging studies have identified a network of distinct face-selective regions in the ventral occipito-temporal cortex (VOTC), with a right hemispheric dominance. To date, there is no evidence for this hemispheric and regional specialization with direct measures of brain activity. To address this gap in knowledge, we recorded local neurophysiological activity from 1,678 contact electrodes implanted in the VOTC of a large group of epileptic patients (n = 28). They were presented with natural images of objects at a rapid fixed rate (six images per second: 6 Hz), with faces interleaved as every fifth stimulus (i.e., 1.2 Hz). High signal-to-noise ratio face-selective responses were objectively (i.e., exactly at the face stimulation frequency) identified and quantified throughout the whole VOTC. Face-selective responses were widely distributed across the whole VOTC, but also spatially clustered in specific regions. Among these regions, the lateral section of the right middle fusiform gyrus showed the largest face-selective response by far, offering, to our knowledge, the first supporting evidence of two decades of neuroimaging observations with direct neural measures. In addition, three distinct regions with a high proportion of face-selective responses were disclosed in the right ventral anterior temporal lobe, a region that is undersampled in neuroimaging because of magnetic susceptibility artifacts. A high proportion of contacts responding only to faces (i.e., “face-exclusive” responses) were found in these regions, suggesting that they contain populations of neurons involved in dedicated face-processing functions. Overall, these observations provide a comprehensive mapping of visual category selectivity in the whole human VOTC with direct neural measures.

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Buchsbaum, Bradley R., Sabrina Lemire-Rodger, Candice Fang y Hervé Abdi. "The Neural Basis of Vivid Memory Is Patterned on Perception". Journal of Cognitive Neuroscience 24, n.º 9 (septiembre de 2012): 1867–83. http://dx.doi.org/10.1162/jocn_a_00253.

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When we have a rich and vivid memory for a past experience, it often feels like we are transported back in time to witness once again this event. Indeed, a perfect memory would exactly mimic the experiential quality of direct sensory perception. We used fMRI and multivoxel pattern analysis to map and quantify the similarity between patterns of activation evoked by direct perception of a diverse set of short video clips and the vivid remembering, with closed eyes, of these clips. We found that the patterns of distributed brain activation during vivid memory mimicked the patterns evoked during sensory perception. Using whole-brain patterns of activation evoked by perception of the videos, we were able to accurately classify brain patterns that were elicited when participants tried to vividly recall those same videos. A discriminant analysis of the activation patterns associated with each video revealed a high degree (explaining over 80% of the variance) of shared representational similarity between perception and memory. These results show that complex, multifeatured memory involves a partial reinstatement of the whole pattern of brain activity that is evoked during initial perception of the stimulus.

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Norris, Scott A., Aimee E. Morris, Meghan C. Campbell, Morvarid Karimi, Babatunde Adeyemo, Randal C. Paniello, Abraham Z. Snyder, Steven E. Petersen, Jonathan W. Mink y Joel S. Perlmutter. "Regional, not global, functional connectivity contributes to isolated focal dystonia". Neurology 95, n.º 16 (10 de septiembre de 2020): e2246-e2258. http://dx.doi.org/10.1212/wnl.0000000000010791.

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ObjectiveTo test the hypothesis that there is shared regional or global functional connectivity dysfunction in a large cohort of patients with isolated focal dystonia affecting different body regions compared to control participants. In this case-control study, we obtained resting-state MRI scans (three or four 7.3-minute runs) with eyes closed in participants with focal dystonia (cranial [17], cervical [13], laryngeal [18], or limb [10]) and age- and sex-matched controls.MethodsRigorous preprocessing for all analyses was performed to minimize effect of head motion during scan acquisition (dystonia n = 58, control n = 47 analyzed). We assessed regional functional connectivity by computing a seed-correlation map between putamen, pallidum, and sensorimotor cortex and all brain voxels. We assessed significant group differences on a cluster-wise basis. In a separate analysis, we applied 300 seed regions across the cortex, cerebellum, basal ganglia, and thalamus to comprehensively sample the whole brain. We obtained participant whole-brain correlation matrices by computing the correlation between seed average time courses for each seed pair. Weighted object-oriented data analysis assessed group-level whole-brain differences.ResultsParticipants with focal dystonia had decreased functional connectivity at the regional level, within the striatum and between lateral primary sensorimotor cortex and ventral intraparietal area, whereas whole-brain correlation matrices did not differ between focal dystonia and control groups. Rigorous quality control measures eliminated spurious large-scale functional connectivity differences between groups.ConclusionRegional functional connectivity differences, not global network level dysfunction, contributes to common pathophysiologic mechanisms in isolated focal dystonia. Rigorous quality control eliminated spurious large-scale network differences between patients with focal dystonia and control participants.

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Ogoh, Shigehiko, Mads K. Dalsgaard, Chie C. Yoshiga, Ellen A. Dawson, David M. Keller, Peter B. Raven y Niels H. Secher. "Dynamic cerebral autoregulation during exhaustive exercise in humans". American Journal of Physiology-Heart and Circulatory Physiology 288, n.º 3 (marzo de 2005): H1461—H1467. http://dx.doi.org/10.1152/ajpheart.00948.2004.

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We investigated whether dynamic cerebral autoregulation is affected by exhaustive exercise using transfer-function gain and phase shift between oscillations in mean arterial pressure (MAP) and middle cerebral artery (MCA) mean blood flow velocity ( Vmean). Seven subjects were instrumented with a brachial artery catheter for measurement of MAP and determination of arterial Pco2 (PaCO2) while jugular venous oxygen saturation (SvO2) was determined to assess changes in whole brain blood flow. After a 10-min resting period, the subjects performed dynamic leg-cycle ergometry at 168 ± 5 W (mean ± SE) that was continued to exhaustion with a group average time of 26.8 ± 5.8 min. Despite no significant change in MAP during exercise, MCA Vmean decreased from 70.2 ± 3.6 to 57.4 ± 5.4 cm/s, SvO2 decreased from 68 ± 1 to 58 ± 2% at exhaustion, and both correlated to PaCO2 (5.5 ± 0.2 to 3.9 ± 0.2 kPa; r = 0.47; P = 0.04 and r = 0.74; P < 0.001, respectively). An effect on brain metabolism was indicated by a decrease in the cerebral metabolic ratio of O2 to [glucose + one-half lactate] from 5.6 to 3.8 ( P < 0.05). At the same time, the normalized low-frequency gain between MAP and MCA Vmean was increased ( P < 0.05), whereas the phase shift tended to decrease. These findings suggest that dynamic cerebral autoregulation was impaired by exhaustive exercise despite a hyperventilation-induced reduction in PaCO2.

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Liu, Sa, Jun Nie, Yusha Li, Tingting Yu, Dan Zhu y Peng Fei. "Three-dimensional, isotropic imaging of mouse brain using multi-view deconvolution light sheet microscopy". Journal of Innovative Optical Health Sciences 10, n.º 05 (septiembre de 2017): 1743006. http://dx.doi.org/10.1142/s1793545817430064.

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We present a three-dimensional (3D) isotropic imaging of mouse brain using light-sheet fluorescent microscopy (LSFM) in conjunction with a multi-view imaging computation. Unlike common single view LSFM is used for mouse brain imaging, the brain tissue is 3D imaged under eight views in our study, by a home-built selective plane illumination microscopy (SPIM). An output image containing complete structural information as well as significantly improved resolution ([Formula: see text]4 times) are then computed based on these eight views of data, using a bead-guided multi-view registration and deconvolution. With superior imaging quality, the astrocyte and pyramidal neurons together with their subcellular nerve fibers can be clearly visualized and segmented. With further including other computational methods, this study can be potentially scaled up to map the connectome of whole mouse brain with a simple light-sheet microscope.

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Hashemi, Meysam, Anirudh N. Vattikonda, Viktor Sip, Sandra Diaz-Pier, Alexander Peyser, Huifang Wang, Maxime Guye, Fabrice Bartolomei, Marmaduke M. Woodman y Viktor K. Jirsa. "On the influence of prior information evaluated by fully Bayesian criteria in a personalized whole-brain model of epilepsy spread". PLOS Computational Biology 17, n.º 7 (14 de julio de 2021): e1009129. http://dx.doi.org/10.1371/journal.pcbi.1009129.

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Individualized anatomical information has been used as prior knowledge in Bayesian inference paradigms of whole-brain network models. However, the actual sensitivity to such personalized information in priors is still unknown. In this study, we introduce the use of fully Bayesian information criteria and leave-one-out cross-validation technique on the subject-specific information to assess different epileptogenicity hypotheses regarding the location of pathological brain areas based on a priori knowledge from dynamical system properties. The Bayesian Virtual Epileptic Patient (BVEP) model, which relies on the fusion of structural data of individuals, a generative model of epileptiform discharges, and a self-tuning Monte Carlo sampling algorithm, is used to infer the spatial map of epileptogenicity across different brain areas. Our results indicate that measuring the out-of-sample prediction accuracy of the BVEP model with informative priors enables reliable and efficient evaluation of potential hypotheses regarding the degree of epileptogenicity across different brain regions. In contrast, while using uninformative priors, the information criteria are unable to provide strong evidence about the epileptogenicity of brain areas. We also show that the fully Bayesian criteria correctly assess different hypotheses about both structural and functional components of whole-brain models that differ across individuals. The fully Bayesian information-theory based approach used in this study suggests a patient-specific strategy for epileptogenicity hypothesis testing in generative brain network models of epilepsy to improve surgical outcomes.

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Shi, Zilun, Chris Dawson, Stephen L. W. On y Malik Altaf Hussain. "Partial Proteome Map of Campylobacter Jejuni Strain Nctc11168 by Gel-Free Proteomics Analysis". International Journal of Applied Sciences and Biotechnology 2, n.º 4 (25 de diciembre de 2014): 464–77. http://dx.doi.org/10.3126/ijasbt.v2i4.11253.

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A proteome map of the foodborne pathogen Campylobacter jejuni NCTC11168 was analyzed using a state-of-the-art gel-free proteomic approach for the first time. A whole cell protein extract was prepared from the C. jejuni strain NCTC11168 grown in brain heart infusion (BHI) broth at 42°C under microaerobic conditions. A gel-free technique using isobaric tags for relative and absolute quantitation (iTRAQ) was employed to create a protein expression profile of the strain. Liquid chromatography-mass spectrometry (LC-MS/MS) was used to identify the proteins. Protein functionalities were searched to classify them. A total of 235 proteins were identified in the whole cell protein fraction of C. jejuni NCTC11168 cells using iTRAQ analysis. Functional grouping of the identified proteins showed that forty percent of these proteins were associated with energy metabolism, protein synthesis and genetic information processing. iTRAQ was faster, easier and proved more sensitive than two-dimensional gel-based proteomics approaches previously applied to C. jejuni, making it an attractive tool for further studies of cellular physiological response. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11253 Int J Appl Sci Biotechnol, Vol. 2(4): 464-477

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Ustinin, M. N., S. D. Rykunov, A. I. Boyko y O. A. Maslova. "Reconstruction of the Human Brain Functional Structure Based on the Electroencephalography Data". Mathematical Biology and Bioinformatics 15, n.º 1 (17 de junio de 2020): 106–17. http://dx.doi.org/10.17537/2020.15.106.

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New method for the data analysis was proposed, making it possible to transform multichannel time series into the spatial structure of the system under study. The method was successfully used to investigate biological and physical objects based on the magnetic field measurements. In this paper we further develop this method to analyze the data of the experiments where the electric field is measured. The brain activity in the state of subject “eyes closed” was registered by the 19-channel electric encephalograph, using the 10-20 scheme. The electroencephalograms were obtained in resting state and with arbitrary hands motions. Detailed multichannel spectra were obtained by the Fourier transform of the whole time series. All spectral data revealed the broad alpha rhythm peak in the frequency band 9-12 Hz. For all spectral components in this band the inverse problem was solved, and the 3D map of the brain activity was calculated. The inverse problem was solved in elementary current dipole model for one-layer spherical conductor without any restrictions for the source position. The combined analysis of the magnetic resonance image and the brain functional structure leads to the conclusion that this structure generally corresponds to the modern knowledge about the alpha rhythm. The 3D map of the vector field of the dominating directions of the alpha rhythm sources was also generated. The proposed method can be used to study the spatial distribution of the brain activity in any spectral band of the electroencephalography data.

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Gatica, Marilyn, Fernando E. Rosas, Pedro A. M. Mediano, Ibai Diez, Stephan P. Swinnen, Patricio Orio, Rodrigo Cofré y Jesus M. Cortes. "High-order functional redundancy in ageing explained via alterations in the connectome in a whole-brain model". PLOS Computational Biology 18, n.º 9 (2 de septiembre de 2022): e1010431. http://dx.doi.org/10.1371/journal.pcbi.1010431.

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The human brain generates a rich repertoire of spatio-temporal activity patterns, which support a wide variety of motor and cognitive functions. These patterns of activity change with age in a multi-factorial manner. One of these factors is the variations in the brain’s connectomics that occurs along the lifespan. However, the precise relationship between high-order functional interactions and connnectomics, as well as their variations with age are largely unknown, in part due to the absence of mechanistic models that can efficiently map brain connnectomics to functional connectivity in aging. To investigate this issue, we have built a neurobiologically-realistic whole-brain computational model using both anatomical and functional MRI data from 161 participants ranging from 10 to 80 years old. We show that the differences in high-order functional interactions between age groups can be largely explained by variations in the connectome. Based on this finding, we propose a simple neurodegeneration model that is representative of normal physiological aging. As such, when applied to connectomes of young participant it reproduces the age-variations that occur in the high-order structure of the functional data. Overall, these results begin to disentangle the mechanisms by which structural changes in the connectome lead to functional differences in the ageing brain. Our model can also serve as a starting point for modeling more complex forms of pathological ageing or cognitive deficits.

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Fields, Melanie E., Kristin P. Guilliams, Dustin K. Ragan, Michael M. Binkley, Cihat Eldeniz, Yasheng Chen, Monica L. Hulbert et al. "Regional oxygen extraction predicts border zone vulnerability to stroke in sickle cell disease". Neurology 90, n.º 13 (2 de marzo de 2018): e1134-e1142. http://dx.doi.org/10.1212/wnl.0000000000005194.

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ObjectiveTo determine mechanisms underlying regional vulnerability to infarction in sickle cell disease (SCD) by measuring voxel-wise cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen utilization (CMRO2) in children with SCD.MethodsParticipants underwent brain MRIs to measure voxel-based CBF, OEF, and CMRO2. An infarct heat map was created from an independent pediatric SCD cohort with silent infarcts and compared to prospectively obtained OEF maps.ResultsFifty-six participants, 36 children with SCD and 20 controls, completed the study evaluation. Whole-brain CBF (99.2 vs 66.3 mL/100 g/min, p < 0.001), OEF (42.7% vs 28.8%, p < 0.001), and CMRO2 (3.7 vs 2.5 mL/100 g/min, p < 0.001) were higher in the SCD cohort compared to controls. A region of peak OEF was identified in the deep white matter in the SCD cohort, delineated by a ratio map of average SCD to control OEF voxels. CMRO2 in this region, which encompassed the CBF nadir, was low relative to all white matter (p < 0.001). Furthermore, this peak OEF region colocalized with regions of greatest infarct density derived from an independent SCD cohort.ConclusionsElevated OEF in the deep white matter identifies a signature of metabolically stressed brain tissue at increased stroke risk in pediatric patients with SCD. We propose that border zone physiology, exacerbated by chronic anemic hypoxia, explains the high risk in this region.

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Fields, Melanie E., Kristin P. Guilliams, Dustin Ragan, Cihat Eldeniz, Michael Binkley, Monica L. Hulbert, Katie D. Vo et al. "Elevations in MR Measurements of Whole Brain and Regional Cerebral Blood Flow and Oxygen Extraction Fraction Suggest Cerebral Metabolic Stress in Children with Sickle Cell Disease Unaffected By Overt Stroke". Blood 126, n.º 23 (3 de diciembre de 2015): 69. http://dx.doi.org/10.1182/blood.v126.23.69.69.

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Abstract Positron emission tomography (PET) studies have shown that the brain increases cerebral blood flow (CBF) and oxygen extraction fraction (OEF, the fraction of oxygen brain tissue extracts from blood) when oxygen delivery is compromised in adult ischemic stroke. Children with sickle cell disease (SCD) have higher CBF compared to healthy children, suggesting that autoregulatory mechanisms, compensating for compromised oxygen delivery, may underlie the pathophysiology of ischemic stroke in SCD. Until now, evaluation of cerebral oxygen metabolism in children with SCD has been limited to measurement of CBF due to the radiation risks of PET. We used a MR sequence that measures voxel-wise OEF to test our hypothesis that children with sickle cell disease will have elevated whole brain and regional OEF when compared to typically developing, sibling controls without SCD. Thirty-six participants, 8 controls and 28 with SCD (26 HbSS and 2 HbSB0), ages 5-21 years, were recruited from St. Louis Children's Hospital. Participants underwent brain MRI with measurement of CBF via pseudo-continuous arterial spin labeling and OEF via a novel processing of asymmetric spin echo sequence that measures tissue deoxyhemoglobin. CBF and OEF maps were individually co-registered to corresponding T1 images with FMRIB's Linear Image Registration Tool, and gray and white matter were segmented with FMRIB's Automated Segmentation Tool. Visual inspection identified a region of high OEF within the deep white matter of the frontal and parietal lobes in the majority of subjects (figure 1 a,b). OEF maps from control and SCD participants were coregistered and averaged into a single map, and then an OEF threshold of 47.5% was applied to demarcate this "high OEF region" (figure 1c). Hemoglobin (Hb) and hematocrit were obtained in SCD participants, while these values were assumed for the controls. Arterial oxygen content (CaO2) was calculated as 1.36 x Hb x SpO2. Comparisons were made with a Mann-Whitney U test or Student's t-test. Bivariate correlations were tested with Kendall's tau b. Bonferroni correction was used in determining significance. Multivariate linear regression modeling with block entry described covariates associated with CBF. The control and SCD cohorts did not differ in age, gender or SpO2. SCD participants demonstrated higher whole brain, gray matter and white matter CBF and OEF when compared to controls (table 1, figure 1a-b), but there was no difference in whole brain or segmented measures of CBF and OEF between SCD participants with structurally normal brain MRIs (n=16) and silent infarcts (n=12). SCD participants' OEF was higher within the "high OEF region" when compared to controls (table 1), but the regional OEF did not differ between SCD participants with structurally normal brain MRIs versus silent infarcts. Whole brain CBF negatively correlated with age (b = -0.554, p < 0.001), while whole brain OEF did not (b= 0.014, p = 0.921). Lower CaO2 correlated with higher whole brain CBF (b = -0.329, p < 0.016) and higher whole brain OEF (b = -0.587, p < 0.001). CaO2 remained a predictor (β = -0.38, p = 0.009) of CBF when controlling for age (β = -0.63, p < 0.001). We report the first whole brain, segmented and regional analysis of oxygen metabolism, including CBF and OEF, in a pediatric SCD cohort unaffected by overt stroke. Elevation in both CBF and OEF in response to low arterial oxygen content suggests children with SCD are chronically compensating to meet the brain's metabolic demands. OEF is more elevated in children with SCD when compared to healthy controls within the "high OEF region," which coincides with previously reported locations of silent infarcts. We propose that the "high OEF region" provides a tissue signature of vulnerable, metabolically stressed brain that is at risk for future stroke. Disclosures Fields: Neurophage: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

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Liu, Bin, Yuan Feng, Ming Yang, Jing-ya Chen, Jing Li, Zhi-chun Huang y Ling-ling Zhang. "Functional Connectivity in Patients With Sensorineural Hearing Loss Using Resting-State MRI". American Journal of Audiology 24, n.º 2 (junio de 2015): 145–52. http://dx.doi.org/10.1044/2015_aja-13-0068.

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Purpose This study was undertaken to evaluate whole-brain functional connectivity changes related to auditory cortex in patients with left-sided sensorineural hearing loss (SNHL) using resting-state functional connectivity magnetic resonance imaging. Method Imaging was performed in 19 patients with left-sided SNHL and 35 individuals in the control group without SNHL. Data were collected and analyzed to map functional connectivity using the left/right primary auditory cortex as the region of interest to identify global differences between patients with SNHL and the control group. Results In comparison to the control group, the SNHL group was found to have significant functional connectivity changes in the auditory system, recognition network, visual cortex, and language network. Conclusion These findings suggest that functional brain alterations in unilateral SNHL patients may indicate reorganizations that occur in response to auditory deficits.

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Favre, Hugues, Mathieu Pernot, Mickael Tanter y Clément Papadacci. "Boosting transducer matrix sensitivity for 3D large field ultrasound localization microscopy using a multi-lens diffracting layer: a simulation study". Physics in Medicine & Biology 67, n.º 8 (7 de abril de 2022): 085009. http://dx.doi.org/10.1088/1361-6560/ac5f72.

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Abstract Mapping blood microflows of the whole brain is crucial for early diagnosis of cerebral diseases. Ultrasound localization microscopy (ULM) was recently applied to map and quantify blood microflows in 2D in the brain of adult patients down to the micron scale. Whole brain 3D clinical ULM remains challenging due to the transcranial energy loss which significantly reduces the imaging sensitivity. Large aperture probes with a large surface can increase both resolution and sensitivity. However, a large active surface implies thousands of acoustic elements, with limited clinical translation. In this study, we investigate via simulations a new high-sensitive 3D imaging approach based on large diverging elements, combined with an adapted beamforming with corrected delay laws, to increase sensitivity. First, pressure fields from single elements with different sizes and shapes were simulated. High directivity was measured for curved element while maintaining high transmit pressure. Matrix arrays of 256 elements with a dimension of 10 × 10 cm with small (λ/2), large (4λ), and curved elements (4λ) were compared through point spread functions analysis. A large synthetic microvessel phantom filled with 100 microbubbles per frame was imaged using the matrix arrays in a transcranial configuration. 93% of the bubbles were detected with the proposed approach demonstrating that the multi-lens diffracting layer has a strong potential to enable 3D ULM over a large field of view through the bones.

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Lee, Dongha y Hae-Jeong Park. "A populational connection distribution map for the whole brain white matter reveals ordered cortical wiring in the space of white matter". NeuroImage 254 (julio de 2022): 119167. http://dx.doi.org/10.1016/j.neuroimage.2022.119167.

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Baracho, Nilo César do Vale, Guilherme Pedrosa Guizelli, Beatriz Leone Carmello, Danielle de Souza Sanches, Felipe Moraes Costa Silva, José Marcos dos Reis y Jarbas de Brito. "Cardiovascular and hematologic effects produced by chronic treatment with etoricoxib in normotensive rats". Acta Cirurgica Brasileira 24, n.º 3 (junio de 2009): 206–10. http://dx.doi.org/10.1590/s0102-86502009000300008.

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PURPOSE: Evaluate the cardiovascular and hematological effects produced by chronic treatment with two dosis of etoricoxib in Wistar normotensive rats. METHODS: Thirty rats have been used and divided into one control group and two etoricoxib (10mg/kg and 30mg/kg) treatments groups for 60 days. The mean arterial pressure (MAP) was taken during the whole experimental period and at the end of this period, under anesthesia blood samples were taken, and further the withdrawn of the aorta, heart, brain, liver, and kidneys for the anatomopathologic study. RESULTS: The treatment with etoricoxib (30mg/Kg) produced a significant increase of the MAP from the 28th day of the experiment and from the platelets when compared to the control group and to the group treated with 10mg/Kg, besides producing a highly significant difference in hematocrit and in the red blood cells in relation to the control group. On the other hand the treatment with etoricoxib has not caused histopathological changes when compared to the control. CONCLUSION: These data show that the chronic treatment with etoricoxib leads to increase of the MAP, and to important hematological changes which seem to be associated to the hemoconcentration although not producing anatomopathological significant changes.

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Hiroki, Masahiko, Naofumi Kajimura, Takeshi Uema, Kenichi Ogawa, Masami Nishikawa, Masaaki Kato, Tsuyoshi Watanabe et al. "Effect of Benzodiazepine Hypnotic Triazolam on Relationship of Blood Pressure and Paco2 to Cerebral Blood Flow During Human Non-Rapid Eye Movement Sleep". Journal of Neurophysiology 95, n.º 4 (abril de 2006): 2293–303. http://dx.doi.org/10.1152/jn.00114.2005.

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We sought to clarify the effect of short-acting benzodiazepine hypnotic on the relationship of arterial blood pressure and arterial partial pressure of carbon dioxide (Paco2) to regional cerebral blood flow (rCBF) during human non-rapid-eye-movement (non-REM) sleep. Nine young normal volunteers were treated in a randomized, crossover design with triazolam or placebo and underwent positron emission tomography at night. During wakefulness and stage 2 and slow wave (stages 3 and 4) sleep, we measured mean arterial blood pressure (MAP), Paco2, and absolute CBF. With triazolam compared to placebo, MAP reduced gradually. During stage 2 sleep, Paco2 increased and whole-brain mean CBF decreased. With triazolam, relative rCBF of the left orbital basal forebrain decreased more during stage 2 than slow wave sleep, whereas absolute CBF of the occipital cortex and cerebral white matter remained constant. During triazolam-induced stage 2 sleep, absolute CBF of the cerebral white matter correlated more strongly to both MAP and Paco2 than during placebo sleep and also correlated more strongly to both MAP and Paco2 than absolute CBF of the occipital cortex. In the frontal white matter, during triazolam-induced stage 2 sleep compared to wakefulness, absolute CBF was significantly better correlated to MAP, but not to Paco2. During triazolam-induced stage 2, the cerebral white matter may receive a modulated CBF regulation having the strengthened relationship of Paco2 to CBF and, more locally, the frontal white matter may depend precariously on CBF regulation.

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Zhang, Weiguo, Bing S. Huang y Frans H. H. Leenen. "Brain renin-angiotensin system and sympathetic hyperactivity in rats after myocardial infarction". American Journal of Physiology-Heart and Circulatory Physiology 276, n.º 5 (1 de mayo de 1999): H1608—H1615. http://dx.doi.org/10.1152/ajpheart.1999.276.5.h1608.

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Blockade of brain “ouabain” prevents the sympathetic hyperactivity and impairment of baroreflex function in rats with congestive heart failure (CHF). Because brain “ouabain” may act by activating the brain renin-angiotensin system (RAS), the aim of the present study was to assess whether chronic treatment with the AT1-receptor blocker losartan given centrally normalizes the sympathetic hyperactivity and impairment of baroreflex function in Wistar rats with CHF postmyocardial infarction (MI). After left coronary artery ligation (2 or 6 wk), rats received either intracerebroventricular losartan (1 mg ⋅ kg−1 ⋅ day−1, CHF-Los) or vehicle (CHF-Veh) by osmotic minipumps. To assess possible peripheral effects of intracerebroventricular losartan, one set of CHF rats received the same rate of losartan subcutaneously. Sham-operated rats served as control. After 2 wk of treatment, mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) at rest and in response to air-jet stress and intracerebroventricular injection of the α2-adrenoceptor-agonist guanabenz were measured in conscious animals. Arterial baroreflex function was evaluated by ramp changes in MAP. Compared with sham groups, CHF-Veh groups showed impaired arterial baroreflex control of HR and RSNA, increased sympathoexcitatory and pressor responses to air-jet stress, and increased sympathoinhibitory and hypotensive responses to guanabenz. The latter is consistent with decreased activity in sympathoinhibitory pathways. Chronic intracerebroventricular infusion of losartan largely normalized these abnormalities. In CHF rats, the same rate of infusion of losartan subcutaneously was ineffective. In sham-operated rats, losartan intracerebroventricularly or subcutaneously did not affect sympathetic activity. We conclude that the chronic increase in sympathoexcitation, decrease in sympathoinhibition, and desensitized baroreflex function in CHF all appear to depend on the brain RAS, since this whole pattern of changes can be normalized by chronic central AT1-receptor blockade with losartan.

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Englund, Erin K., Maria A. Fernández-Seara, Ana E. Rodríguez-Soto, Hyunyeol Lee, Zachary B. Rodgers, Marta Vidorreta, John A. Detre y Felix W. Wehrli. "Calibrated fMRI for dynamic mapping of CMRO2 responses using MR-based measurements of whole-brain venous oxygen saturation". Journal of Cerebral Blood Flow & Metabolism 40, n.º 7 (8 de agosto de 2019): 1501–16. http://dx.doi.org/10.1177/0271678x19867276.

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Functional MRI (fMRI) can identify active foci in response to stimuli through BOLD signal fluctuations, which represent a complex interplay between blood flow and cerebral metabolic rate of oxygen (CMRO2) changes. Calibrated fMRI can disentangle the underlying contributions, allowing quantification of the CMRO2 response. Here, whole-brain venous oxygen saturation ( Y v) was computed alongside ASL-measured CBF and BOLD-weighted data to derive the calibration constant, M, using the proposed Y v-based calibration. Data were collected from 10 subjects at 3T with a three-part interleaved sequence comprising background-suppressed 3D-pCASL, 2D BOLD-weighted, and single-slice dual-echo GRE (to measure Y v via susceptometry-based oximetry) acquisitions while subjects breathed normocapnic/normoxic, hyperoxic, and hypercapnic gases, and during a motor task. M was computed via Y v-based calibration from both hypercapnia and hyperoxia stimulus data, and results were compared to conventional hypercapnia or hyperoxia calibration methods. Mean M in gray matter did not significantly differ between calibration methods, ranging from 8.5 ± 2.8% (conventional hyperoxia calibration) to 11.7 ± 4.5% (Yv-based calibration in response to hyperoxia), with hypercapnia-based M values between ( p = 0.56). Relative CMRO2 changes from finger tapping were computed from each M map. CMRO2 increased by ∼20% in the motor cortex, and good agreement was observed between the conventional and proposed calibration methods.

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De-Giorgio, Fabio, Gabriele Ciasca, Gennaro Fecondo, Alberto Mazzini, Riccardo Di Santo, Marco De Spirito y Vincenzo L. Pascali. "Post mortem computed tomography meets radiomics: a case series on fractal analysis of post mortem changes in the brain". International Journal of Legal Medicine 136, n.º 3 (3 de marzo de 2022): 719–27. http://dx.doi.org/10.1007/s00414-022-02801-5.

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AbstractEstimating the post-mortem interval is a fundamental, albeit challenging task in forensic sciences. To this aim, forensic practitioners need to assess post-mortem changes through a plethora of different methods, most of which are inherently qualitative, thus providing broad time intervals rather than precise determinations. This challenging problem is further complicated by the influence of environmental factors, which modify the temporal dynamics of post-mortem changes, sometimes in a rather unpredictable fashion. In this context, the search for quantitative and objective descriptors of post-mortem changes is highly demanded. In this study, we used computed tomography (CT) to assess the post-mortem anatomical modifications occurring in the time interval 0–4 days after death in the brain of four corpses. Our results show that fractal analysis of CT brain slices provides a set of quantitative descriptors able to map post-mortem changes over time throughout the whole brain. Although incapable of producing a direct estimation of the PMI, these descriptors could be used in combination with other more established methods to improve the accuracy and reliability of PMI determination.

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Bueichekú, Elisenda, Maite Aznárez-Sanado, Ibai Diez, Federico d’Oleire Uquillas, Laura Ortiz-Terán, Abid Y. Qureshi, Maria Suñol et al. "Central neurogenetic signatures of the visuomotor integration system". Proceedings of the National Academy of Sciences 117, n.º 12 (6 de marzo de 2020): 6836–43. http://dx.doi.org/10.1073/pnas.1912429117.

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Visuomotor impairments characterize numerous neurological disorders and neurogenetic syndromes, such as autism spectrum disorder (ASD) and Dravet, Fragile X, Prader–Willi, Turner, and Williams syndromes. Despite recent advances in systems neuroscience, the biological basis underlying visuomotor functional impairments associated with these clinical conditions is poorly understood. In this study, we used neuroimaging connectomic approaches to map the visuomotor integration (VMI) system in the human brain and investigated the topology approximation of the VMI network to the Allen Human Brain Atlas, a whole-brain transcriptome-wide atlas of cortical genetic expression. We found the genetic expression of four genes—TBR1, SCN1A, MAGEL2, and CACNB4—to be prominently associated with visuomotor integrators in the human cortex. TBR1 gene transcripts, an ASD gene whose expression is related to neural development of the cortex and the hippocampus, showed a central spatial allocation within the VMI system. Our findings delineate gene expression traits underlying the VMI system in the human cortex, where specific genes, such as TBR1, are likely to play a central role in its neuronal organization, as well as on specific phenotypes of neurogenetic syndromes.

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Tonn, Bruce. "Will Psychological Disorders Afflict Uploaded Personalities?" World Futures Review 3, n.º 4 (noviembre de 2011): 25–34. http://dx.doi.org/10.1177/194675671100300404.

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Uploading human minds into computer systems is an intriguing concept. Will this process become part of our evolutionary future? This paper begins by arguing that successfully replicating human minds in virtual environments will require more than computing power and the ability to transfer the information content of neural connections into computer memory. Virtual minds must also be equipped with certain properties of the human biological mind that may prove to be not easily transferable. These include psychological motivations and even our collective unconsciousness. Lacking these, virtual minds could suffer from a wide range of serious psychological disorders. Efforts to treat such disorders with “program” fixes would invalidate any plausible claim that a virtual mind had the same ‘identity’ as its biological ancestor, and also raise perplexing ethical issues. The paper next provides a theoretical psychological framework for these assertions, and goes on to explore nine specific psychological disorders that could afflict virtual personalities. The paper then concludes by identifying several ethical issues that might arise from attempts to “fix” the psychological problems of virtual personalities. Uploading would involve first freezing a brain, then slicing it, then scanning the slices with some high- resolution scanning technique, then using automated image processing software to reconstruct and tag a very detailed 3-D map of the original brain. The map would show all the neurons, the matrix of their synaptic interconnections, the strengths of these connections, and other relevant detail. Using computational models of how these basic elements operate, the whole brain could then be emulated on a sufficiently capacious computer.—Nick Bostrom (2004)

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Hori, Yuki, Justine C. Cléry, Janahan Selvanayagam, David J. Schaeffer, Kevin D. Johnston, Ravi S. Menon y Stefan Everling. "Interspecies activation correlations reveal functional correspondences between marmoset and human brain areas". Proceedings of the National Academy of Sciences 118, n.º 37 (7 de septiembre de 2021): e2110980118. http://dx.doi.org/10.1073/pnas.2110980118.

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The common marmoset has enormous promise as a nonhuman primate model of human brain functions. While resting-state functional MRI (fMRI) has provided evidence for a similar organization of marmoset and human cortices, the technique cannot be used to map the functional correspondences of brain regions between species. This limitation can be overcome by movie-driven fMRI (md-fMRI), which has become a popular tool for noninvasively mapping the neural patterns generated by rich and naturalistic stimulation. Here, we used md-fMRI in marmosets and humans to identify whole-brain functional correspondences between the two primate species. In particular, we describe functional correlates for the well-known human face, body, and scene patches in marmosets. We find that these networks have a similar organization in both species, suggesting a largely conserved organization of higher-order visual areas between New World marmoset monkeys and humans. However, while face patches in humans and marmosets were activated by marmoset faces, only human face patches responded to the faces of other animals. Together, the results demonstrate that higher-order visual processing might be a conserved feature between humans and New World marmoset monkeys but that small, potentially important functional differences exist.

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Alderman, Sarah L. y Mathilakath M. Vijayan. "11β-Hydroxysteroid dehydrogenase type 2 in zebrafish brain: a functional role in hypothalamus-pituitary-interrenal axis regulation". Journal of Endocrinology 215, n.º 3 (5 de octubre de 2012): 393–402. http://dx.doi.org/10.1530/joe-12-0379.

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The type 2, 11β-hydroxysteroid dehydrogenase (Hsd11b2) converts active glucocorticoids to their inactive derivatives (e.g. cortisol to cortisone). In most vertebrates, Hsd11b2 is essential for conferring aldosterone-specific actions in mineralocorticoid target tissues and for protecting glucocorticoid-sensitive tissues during stress. However, teleosts do not synthesize aldosterone, and the function of Hsd11b2 is poorly defined. The distribution of Hsd11b2 in nonmammalian brain is also largely unexplored. We tested the hypothesis that modulation of brain Hsd11b2 activity is involved in stressor-mediated cortisol regulation in zebrafish (Danio rerio). In adult zebrafish, the stress effect on Hsd11b2 expression in the brain was tested using acute air exposure followed by recovery over a 24-h period.hsd11b2transcripts were found in nearly all peripheral tissues examined, and a spatial map of its mRNA abundance in unstressed zebrafish brain revealed extensive distribution. Stressor exposure increased the conversion of3H-cortisol to3H-cortisone indicating enhanced Hsd11b2 activity in zebrafish brain. Promoter analysis of zebrafishhsd11b2gene revealed putative sites for cortisol-mediated transcriptional regulation of this gene. Furthermore, inhibition of Hsd11b2 activity by 18β-glycyrrhetinic acid resulted in elevated whole-body cortisol levels and preoptic area mRNA abundance of corticotropin-releasing factor and mineralocorticoid receptor. Taken together, our results underscore an important role for brain Hsd11b2 involvement in the negative feedback regulation of cortisol poststress in zebrafish.

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Lindhe, Örjan, Per Almqvist, Matts Kågedal, Sven-Åke Gustafsson, Mats Bergström, Dag Nilsson y Gunnar Antoni. "Autoradiographic Mapping of 5-HT1B/1D Binding Sites in the Rhesus Monkey Brain Using [carbonyl-11C]zolmitriptan". International Journal of Molecular Imaging 2011 (12 de octubre de 2011): 1–6. http://dx.doi.org/10.1155/2011/694179.

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Zolmitriptan is a serotonin 5-HT1B/1D receptor agonist that is an effective and well-tolerated drug for migraine treatment. In a human positron emission tomography study, [11C]zolmitriptan crossed the blood-brain barrier but no clear pattern of regional uptake was discernable. The objective of this study was to map the binding of [11C]zolmitriptan in Rhesus monkey brain using whole hemisphere in vitro autoradiography with [11C]zolmitriptan as a radioligand. In saturation studies, [11C]zolmitriptan showed specific (90%) binding to a population of high-affinity binding sites (Kd 0.95–5.06 nM). There was regional distribution of binding sites with the highest density in the ventral pallidum, followed by the external globus pallidus, substantia nigra, visual cortex, and nucleus accumbens. In competitive binding studies with 5-HT1 receptor antagonists, [11C]zolmitriptan binding was blocked by selective 5-HT1B and 5-HT1D ligands in all target areas. There was no appreciable change in binding with the addition of a 5-HT1A receptor antagonist.

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Dise, Joseph, Christopher Abraham, Douglas Caruthers, Sasa Mutic y Clifford Robinson. "RADI-19. EVALUATION OF BRAIN METASTASIS LOCAL CONTROL POST RADIOSURGERY VIA MACHINE LEARNING AND RADIOMICS". Neuro-Oncology Advances 1, Supplement_1 (agosto de 2019): i25. http://dx.doi.org/10.1093/noajnl/vdz014.111.

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Abstract Stereotactic radiosurgery can be used to treat multiple, surgically inaccessible, metastatic brain lesions in a single, minimally invasive outpatient procedure. For brain metastasis, stereotactic radiosurgery can provide excellent local control depending on the robustness of the treatment plan. Previous studies have been performed correlating key radiation planning factors to higher local control probability such as tumor size and maximum dose. However, a separate non-inferiority study demonstrated that higher prescription isodose lines (in excess of 70% or higher) did not correlate to local failure. The previous works were limited to shallow feature levels regarding only the dicom plan information and lacked a predictive model. In order to address these conflicting conclusions and to support clinical decision making, we propose a radiosurgery informatics pipeline to support testing these hypotheses with observational data. First, a multidisciplinary team generated a mind-map of relevant information to inform database design. Portions of this mind-map were implemented in a relational database system (PorstgreSQL), and populated with information from 1024 patients treated for brain metastasis via stereotactic radiosurgery. Clinical information were derived from curated databases and the array of intervention variables were mined from the DICOM RT plans, structure sets, images and dose via MATLAB scripts. These factors include, but are not limited to, radiation dosimetry, prior whole brain radiation, radiomic imaging features, prior radiosurgery status, and physician determined local control status. From this pipeline, we plan to use a multi-level feature-based supervised machine learning approach that will be created via boosting to predict local control in patients using local failure timing, or lack thereof, provided by physician. To control for local failure observer bias, an unsupervised machine learning model via random trees will be created to predict clusters of patient parameters with similar local control rates.

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Huang, Jie. "A Holistic Analysis of Individual Brain Activity Revealed the Relationship of Brain Areal Activity with the Entire Brain’s Activity". Brain Sciences 13, n.º 1 (20 de diciembre de 2022): 6. http://dx.doi.org/10.3390/brainsci13010006.

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The relationship between brain areal activity and the entire brain’s activity is unknown, and understanding this relationship is imperative for understanding the neural mechanisms of human brain function at systems level. The complex activity of human brains varies from area to area and from time to time across the whole brain. BOLD-fMRI measures this spatiotemporal activity at a large-scale systems level. The BOLD time signal of an area reflects a collective neuronal activity of over one million neurons under that area, and the temporal correlation of this time signal with that of every point in the brain yields a full spatial map that characterizes the entire brain’s functional co-activity (FC) relative to that area’s activity. Here we show a quantitative relationship between brain areal activity and the activity of the entire brain. The temporal correlation coefficient r of the signal time courses of two areas quantifies the degree of co-activity between the two areas, and the spatial correlation coefficient R of their corresponding two FC maps quantifies the co-activity between these two maps. We found that a modified sigmoid function quantified this R with r, i.e., Rr=1+ra−1−ra1+ra+1−ra, revealing a relationship between the activity of brain areas and that of the entire brain. The parameter a in this equation was found to be associated with the mean degree of the temporal co-activity among all brain areas, and its value was brain functional state dependent too. Our study demonstrated a novel approach for analyzing fMRI data to holistically characterize the entire brain’s activity quantitatively for any brain functional state in individual humans.

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SCHMIDT, G., G. ZAMORA-LÓPEZ y J. KURTHS. "SIMULATION OF LARGE SCALE CORTICAL NETWORKS BY INDIVIDUAL NEURON DYNAMICS". International Journal of Bifurcation and Chaos 20, n.º 03 (marzo de 2010): 859–67. http://dx.doi.org/10.1142/s0218127410026149.

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Understanding the functional dynamics of the mammalian brain is one of the central aims of modern neuroscience. Mathematical modeling and computational simulations of neural networks can help in this quest. In recent publications, a multilevel model has been presented to simulate the resting-state dynamics of the cortico-cortical connectivity of the mammalian brain. In the present work we investigate how much of the dynamical behavior of the multilevel model can be reproduced by a strongly simplified model. We find that replacing each cortical area by a single Rulkov map recreates the patterns of dynamical correlation of the multilevel model, while the outcome of other models and setups mainly depends on the local network properties, e.g. the input degree of each vertex. In general, we find that a simple simulation whose dynamics depends on the global topology of the whole network is far from trivial. A systematic analysis of different dynamical models and coupling setups is required.

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Kaufmann, T., K. C. Skåtun, D. Alnæs, C. L. Brandt, N. T. Doan, I. Agartz, I. S. Melle, O. A. Andreassen y L. T. Westlye. "Disintegration of sensorimotor brain networks in schizophrenia". European Psychiatry 33, S1 (marzo de 2016): S33—S34. http://dx.doi.org/10.1016/j.eurpsy.2016.01.864.

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A large body of literature reported widespread structural and functional abnormalities throughout the brain in schizophrenia spectrum disorders (SZ). Corresponding with the typical symptomatology in SZ where sensory dysfunctions contribute to the core social and cognitive impairment, converging evidence suggests a disturbed interplay between higher-order (cognitive) and lower-order (sensory) regions. This talk will discuss the results of several recent studies, investigating brain connectivity in SZ using functional magnetic resonance imaging data from large samples. Within-network sensorimotor as well as sensorimotor-thalamic aberrations in SZ robustly appear among the core findings across studies, both during performance of cognitive tasks and during rest. We utilized machine learning to distinguish SZ from healthy controls based on connectivity profiles. When classifying on sensorimotor connections alone, not only can we reach accuracies largely above chance but also, these accuracies are as good as when incorporating whole brain connectivity in the classification. Whereas the overall accuracy levels in distinguishing SZ from controls are not useful in a clinical context, these results underline the robustness of the sensorimotor findings on the individual subject level. Targeting the sensory and perceptual domains may thus be key for future research to get a better understanding of the heterogeneity of clinical manifestations in severe mental disorders and to map clinical symptoms to imaging phenotypes.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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Ustinin, M. N., S. D. Rykunov, A. I. Boyko, O. A. Maslova, K. D. Walton y R. R. Llinás. "Estimation of the Directions of Alpha Rhythm Elementary Sources Using the Method of Human Brain Functional Tomography Based On the Magnetic Encephalography Data". Mathematical Biology and Bioinformatics 13, n.º 2 (23 de noviembre de 2018): 426–36. http://dx.doi.org/10.17537/2018.13.426.

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New method for the magnetic encephalography data analysis was proposed. The method transforms multichannel time series into the spatial structure of the human brain activity. In this paper we further develop this method to determine the dominant direction of the electrical sources of brain activity at each node of the calculation grid. We have considered the experimental data, obtained with three 275-channel magnetic encephalographs in New York University, McGill University and Montreal University. The human alpha rhythm phenomenon was selected as a model object. Magnetic encephalograms of the brain spontaneous activity were registered for 5-7 minutes in magnetically shielded room. Detailed multichannel spectra were obtained by the Fourier transform of the whole time series. For all spectral components, the inverse problem was solved in elementary current dipole model and the functional structure of the brain activity was calculated in the frequency band 8-12 Hz. In order to estimate the local activity direction, at the each node of calculation grid the vector of the inverse problem solution was selected, having the maximal spectral power. So, the 3D-map of the brain activity vector field was produced – the directional functional tomogram. Such maps were generated for 15 subjects and some common patterns were revealed in the directions of the alpha rhythm elementary sources. The proposed method can be used to study the local properties of the brain activity in any spectral band and in any brain compartment.

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Minejeva, Oļesja, Zigurds Markovics y Nauris Zdanovskis. "BRAIN CONNECTIONS ANALYSIS USING GRAPH THEORY MEASURES". ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 2 (20 de junio de 2019): 94. http://dx.doi.org/10.17770/etr2019vol2.4141.

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Brain is a part of the organism’s complex structure that performs many functions, which are responsible for the main human abilities: to talk, to hear, to move, to see, etc. The brain consists of several areas that are not only directly connected with the different body systems, but also depend and may affect each other. Researchers and doctors are trying to summarize and visualize these relationships for an important purpose – to get the information about possible reactions of the body in case of various diseases, possibilities of recovery, risks, etc. important issues. Neurologists are looking for ways to "move" through the brain in virtual space for viewing the synapses between different areas. It might be useful to get a general idea of how brain regions are interrelated. The term "connectome", which is the complete structural description of the brain connections, or the map of connections, is used for the common perception of brain relationships. Connectome is a network of thousands of nerve fibres that transmits signals between the special regions responsible for functions such as vision, hearing, movement and memory, and combines these functions in a system that perceives, decides and acts as a whole. So, the relationships of brain neural regions can be represented as a graph with vertices corresponding to specific areas, but edges are links between these areas. This graph can be analysed using quantitative measures, like node degree, centrality, modularity etc. This article discusses the different network measures for the connections between brain's regions. The purpose is to determine the most important areas and the role of individual connections in the general functional brain model.

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Liwang, Josephine K., Hannah C. Bennett, Hyun-Jae Pi y Yongsoo Kim. "Protocol for using serial two-photon tomography to map cell types and cerebrovasculature at single-cell resolution in the whole adult mouse brain". STAR Protocols 4, n.º 1 (marzo de 2023): 102048. http://dx.doi.org/10.1016/j.xpro.2023.102048.

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