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study guide - Copyright (c) 2009 David G. Lavond Recording...

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Copyright (c) 2009 David G. Lavond Recording and Stimulating Neural Activity Ch. 5 THEME studying activity in a particular region Recording of Neural Activity KEY recording during stimulus presentations, decision making, motor activities recordings can be made chronically or acutely chronic recordings can be made over an extended period of time after the animal recovers from surgery acute recordings are made while animal is anesthetized, usually restricted to sensory systems, seldom involve behavioral observatins Recordings with Microelectrodes microelectrodes single-unit recording [description of an array of wires, surgery and sockets, moveable electrodes, amplification] e.g., recordings show that NE and 5-HT neuron activity is inhibited during REM sleep oscilloscope Recordings with Macroelectrodes macroelectrodes recording from the brain as a whole e.g., on brain, on scalp e.g., used to detect and localize seizures for removal ink-writing oscillograph aka polygraph electroencephalograms EEGs BOX Mrs. F operated on for atherosclerotic plaque in left common carotid; surgeons used EEG to monitor blood-flow to brain (insufficient blood flow shows slow waves) Magnetoencephalography magnetoencehalography neuromagnetometers contain several superconducting quantum interference devices SQUIDs detect magnetic fields of neural activity Recording the Brain’s Metabolic and Synaptic Activity KEY increased neural activity results in increased metaolic rate largely as a result of increased activity of ion pumps 2-deoxyglucose 2-DG taken up by active cells but cannot be metabolized measured by autoradiography autoradiography [describes method] immediate early genes Fos a protein produced in the nucleus of a neuron in response to synaptic stimulation positron emission tomography PET method: first inject with radioactive 2-DG, then take scan (similar to CT scanner) to detect decaying positrons, reconstruct picture [thought radioactively labeled 02 ???] very expensive operating cost for CT scanner safety concerns require injection of substances with short half-lifes (110 mins for 2-DG; 2 mins for labeled water) requiring cyclotron -- additional cost functional MRI fMRI much faster image collection measurement of regional metabolism by detecting levels of oxygen in the blood vessels higher resolution than PET RESULT: more detailed information about brain activity Stimulating Neural Activity e.g., activating VMH results in lordosis in the absence of female sex hormones methods electrical stimulation chemical stimulation, e.g. excitatory amino acid (small doses of kainic acid or glutamic acid) cannula CON more complicated than electrical stimulation PRO does not stimulate fibers of passage like electrical stimulation; more localized microiontophoresis allows chemical stimulation of a single cell Photostimulation NEW TOPIC genes for photosensitive proteins found in algae and bacteria are inserted by injecting brain with harmless viruses that infect the area action of photosensitive proteins begins and ends very rapidly
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study guide - Copyright (c) 2009 David G. Lavond Recording...

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