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Neuroscience: Modern Technology & Research (part 2) (Insights into…

- - - - Useful in detecting disorders associated with abnormalities in brain arteries
      - A procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain
    - - An image slice through an organ without the interference of all layers of tissue present in X-ray images
      - X-ray films appear blurry because they are 2-D rendition of our 3-D body
    - - Less radiation than traditional x-ray
      - Enable 'deblurring' of picture & reconstruction of a complete brain image from multiple views
      - Enable process of imaging brain internal structure to become safer & more precise-3D
      - Advantages
        
        safer- The fan shaped beam exposes the body to less radiation than traditional x-rays
        
        more precise- only takes a cross section of an organ, avoiding problem of interference of all the layers of tissue present in x-ray images
        
        clearer image of brain structures-'deblurring' by computer technology 3D
      - Disadvantages
        
        Doesn't indicate when an activity is occurring in the brain
  - - - No X-rays or radioactive material is used (unlike CAT or PET)
      - Resolution of the image is shape / clearer than CAT scans
      - Flexibility- allows the researches to distinguish different structures of the brain- gray/white matter and cerebrospinal fluid
    - - slow- for an image to be generated
      - cannot be used in patients with metallic devices, like pacemakers
      - may cause claustrophobic reaction in some patients
- - - - A test of the function of the brain itself
        
        records the electrical activity on the brain's surface
        
        image the brain while it is performing cognitive task
        
        detect the location and magnitude of brain activity involved in the various types of cognitive functions
      - Non-invasive and painless procedure
        
        Take brief patient history
        
        Apply electrode leads to the patient's scalp
        
        Run the test
      - Tracings/ Recordings of patterns of electrical activity in the brain
      - Provide fine-tuned reading of rapidly occurring changes (MRI too slow to do this)
      - Advantages
        
        Able to trace rapid changes in neural activity
        
        Can record activations in brains of people who are fully conscious & engaged in various activities in natural environment
      - Disadvantages
        
        Invasiveness- relative
        
        Possible interference from movement, heartbeats- blue reading
    - - Subject presented with a stimulus during EEG process
        
        Record voltage change around the stimulus (before and after it ends)
        
        Repetitions of event- average the values
      - Evoked response provides a picture of neural activity changing over time as the brain processes information
  - - - Method of measuring cerebral blood flow while subject carries out cognitive tasks
      - PET scans look at bodily process by detecting the decay products from radioactive tracers injected into the body.
      - Advantages
        
        Provides an image of brain activity as a cognitive task is occurring - locate activity in specific parts of the brain
      - Disadvantages
        
        Requires the use of cyclotron, an expensive equipment to provide the radioactive isotopes (decay easily and needs to be produced each day)
        
        Not as sensitive to changes over milliseconds (in comparison to electrophysiological techniques)
        
        Radioactive material used
    - - Detect changes in magnetic state of blood using MRI scanners with fast imaging techniques- record changes in oxygen level & blood flow in various brain locations as subjects perform various cognitive tasks
      - Determine which parts of the brain are activated by different types of physical sensation or activity
      - Advantages
        
        Provides information about brain structure and function
        
        safer- less harm to patients as no-X-rays or radioactive material is used
        
        allows researchers to infer which locations are involved in specific activities