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Descripción
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| In the last few years, the knowledge about the brain activity has progressed considerably thanks to powerful non-invasive techniques to image the brain anatomy, function and metabolism. Now the brain can be studied up to the cellular level (neurons and even synapses), at the level of neural pathways, or at regional or global levels. The aim can be analyzing the underlying cognitive functions, trying to have hints on how the brain works (usually from healthy volunteers) or to study neuropsychiatric disorders such as neurodegenerative diseases (Alzheimer¿s, Parkinson¿s¿), schizophrenia, vascular diseases, tumors, etc. Non-invasive brain activity analysis is currently based on three different techniques: electroencephalogram/magnetoencephalogram (EEG/MEG), magnetic resonance imaging MRI and positron emission tomography (PET). In this talk we will review what kind of information can be obtained from each modality and how to integrate them to have a unique brain¿s view. Historically the first modality to study non-invasively the brain activity is the EEG, which showed the global activity of the brain, specially the cortical electrical activity. Solving mathematically the so-called ¿inverse problem¿ and using a sufficiently large number of electrodes (in the order of 128), EEG sources can be estimated, adding important spatial information, although with limited spatial resolution. The much more recent recording of magnetic fields in magnetoencephalography (MEG) has improved the obtained features but still the scale at what EEG and MEG see the brain is coarse. Magnetic Resonance Imaging started as a way to see the anatomy (it has the unique capability to differentiate white matter from gray matter), but soon evolved to provide also physiological information (e.g. perfusion to detect vascular problems). As fMRI, it provides information on brain activity based on the hemodynamic changes triggered by the increased neuronal activity. It is then complementary of EEG/MEG, showing superior spatial resolution although worse temporal definition. In the last few years there is a growing interest in combining the information provided by EEG/MEG and fMRI. Although neuron¿s axons are too small for current in vivo resolution, MRI can indirectly track axonal fibers by using Diffusion Tensor Imaging (DTI), the possibility of measuring the diffusion of water molecules in tissues. Then while fMRI shows the information processing, DTI shows the information pathways. Positron Emission Tomography is unique in its capabilities of tracking labeled molecules. With 18F-FDG, it can localize regions with high glucose consumption, of interest in oncology but also to indirectly visualize brain activity. But PET interest is also growing with the appearance of new labeled molecules that can show metabolic activity. A promising molecule for example is 11C-PIB, being studied as a candidate for early diagnosis of Alzheimer¿s disease. Molecular imaging with PET, but also with other techniques like Magnetic Resonance Spectroscopy (MRS) can have a hint on the biochemistry at the cellular level. The integration of all this information is a challenge that will allow us a better understanding of brain¿s activity. | |
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Internacional
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Si |
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Nombre congreso
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Emerging Technologies in Biomedicine ¿Advanced Methods for the Estimation of Human Brain Activity and Connectivity; |
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Entidad organizadora
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COST BM0601 + University of Patras |
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Nacionalidad Entidad
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GRECIA |
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Lugar/Ciudad de impartición
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Patras |
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Fecha inicio
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30/06/2008 |
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Fecha fin
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04/07/2008 |