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Published byRegan Grass Modified over 10 years ago
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Brain imaging techniques PET Mikrolesions Single cell Lesions 2-Deoxyglucose Multi-unit Patch clamp EEG & MEG TMS fMRI Optical Imaging millisecundum sec min hour day year -3 -2 -1 0 1 2 3 4 5 6 7 8 Log time (sec) Lamina Neuron Dendrite Synapse 4 3 2 1 0 -2 -3 -4 Lo g Re sol uti on (m m) Brain Column
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Patch-clamp recordings: a single channel
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Patch-clamp recording techniques
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Even parallel dendritic and somatic patches are possible
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A typical result: the I-V curve
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Electric activity of the brain on different scales
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Lengyel Máté: Egysejt modellek II / Modellek az idegrendszer-kutatásban - ELTE TTK, 2003 tavaszi félév http://www.rmki.kfki.hu/~lmate/kurz/ 77 Discovery of the electricity in animals: 1792 Galvani, De Viribus - Electricitatis in Motu Musculari.
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Lengyel Máté: Egysejt modellek II / Modellek az idegrendszer-kutatásban - ELTE TTK, 2003 tavaszi félév http://www.rmki.kfki.hu/~lmate/kurz/ 88 Discovery of the electroencephalography (EEG) 1924. Hans Berger The first EEG record The alpha rythm Electric signs of epilepsy Investigated the telepathy
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Elektroencephalography (EEG) and magnetoencephalography (MEG)
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EC IC V dV ext ICIC IRIR R EC R IC I axial ICIC IRIR ICIC IRIR I ~ CSD I ~ CSD I ~ CSD The source of the EC potential is the sum of the capacitive and resistive currents The sum of I R is not zero, But the sum of I CSD is zero for the whole cell!
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Multi Electrode Array Original current source density distribution Sink Source Zero T(d) The forward problem
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Multi Electrode Array Original current source density distribution Sink Source Zero T(d) The forward problem
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The origin of the EEG and MEG
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Normal resting EEG
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EEG imaging with dipole localization
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Evoked potentials 20 µV 2 µV
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The auditory evoked potential:
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Extracellular recordings
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Identification of excitatory and inhibitory connections by correlation requires parallel recording of hundreds of neurons.
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Active feedback via electrodes
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Positron emission tomography (PET)
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PET-based functional brain imaging
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The MRI machine
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The BOLD response: the basis of the fMRI
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High resolution functional brain imaging with fMRI
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Mind-reading with fMRI Results: Learning on 1750 pictures Selection from 120 new pics: 92% Selection from 1000 new pics: 82%
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Direction selective neurons in the motor cortex Both the motor and the somato-sensory cortex represents the whole body Each cell is tuned to a specific direction
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Brain-machine interface in monkeys The direction and speed of the planed movement could be determined from the activity of the cells and their directional tuning.
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BMI with invasive electrodes
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BMI with non-invasiv electrodes
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Arm prosthesis driven by the nerves It is more easy to decode the planed motion from the activity of the peripheral nerves.
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