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4 Types of brain imaging techniques: Microelectrode: Examines individual neurons Macroelectrode: Examines brain activity without producing an image (Ex: EEG) Structural Imaging: Shows image of brain structure (EX: CAT scan, MRI) Functional Imaging: Shows image of brain structure and activity (Ex: EEG, MEG/MSI, PET Scan, fMRI) Microelectrode Studies the function of a single neuron. The microelectrode is thinner than a human hair. Ending is charged and inserted into neuron. Changes in neurons documented. Mostly used to study effects of neurotransmitters Macroelectrode Used to obtain an overall picture of the activity in particular regions of the brain. EEG: (electroencephalograph) Electrodes are taped to the scalp to detect brain waves (alpha waves when asleep/relaxed, beta waves when awake/alert). Can’t see through skull, but can show activity in brain. Structural Imaging CAT Scan (aka CT Scan) (computerized axial tomography) Creates 3D images of the brain by combining X-rays from many angles. Structural Imaging (cont’d) MRI (magnetic resonance imaging) Better images than CT scan. Head surrounded by magnetic field & brain exposed to radio waves, which causes hydrogen atoms to be released. Released energy mapped out and made into image. Functional Imaging To see brain’s activity, not just the structure. EEG Imaging: Same as EEG, but detected brain waves transformed into an image instead. Functional Imaging (cont’d) MEG/MSI: Like EEG Imaging, but more precise in where activity is taking place in the brain. (magnetoencephalography/ magnetic source imaging) Functional Imaging (cont’d) PET scan (positron emission tomography) Uses radioactive energy to map brain activity. Person injected with radioactive substance. When substance decays due to activity of cells, positrons emitted. More activity, higher emissions. Mapped into image. Functional Imaging (cont’d) fMRI: (functional MRI) Same as PET scan, but instead measures movement of blood molecules, which is an index of neuron activity Extremely precise images collected rapidly, many times per second. Doesn’t require injection of radioactive materials. 4 Types of brain imaging techniques: Microelectrode: Examines individual neurons Macroelectrode: Examines brain activity without producing an image (Ex: EEG) Structural Imaging: Shows image of brain structure (EX: CAT scan, MRI) Functional Imaging: Shows image of brain structure and activity (Ex: EEG, MEG/MSI, PET Scan, fMRI)