Cognition ch 4

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brianklein
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236210
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Cognition ch 4
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2013-09-21 19:41:42
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cognition
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test 1
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  1. measures of the spatial configuration of different types of tissue in the brain
    structural imaging
  2. measures temporary changes in brain physiology associated with cognitive processing
    functional imaging
  3. constructed according to the amount of x-ray absorption in different types of tissue
    computerized tomography (CT) scans
  4. CT scans cannot distinguish between ____ ____ and ____ _____ in the same way as MRI, and it can not be adapted for
    functional imaging purposes
  5. characteristics of this type of structural imaging device
    • -is completely safe (people can be scanned multiple times)
    • -provides better spatial resolution
    • -better discrimination between white and gray matter
  6. strong magnetic field is applied across the part of the body being scanned, this strong external field is applied and a small fraction of hydrogen nuclei in water alight themselves
    MRI
  7. strength of the magnetic field is measured in units called
    tesla
  8. designed to measure the moment to moment variable characteristics of the brain that may be associated with changes in cognitive processing
    functional imaging
  9. measures the change in blood flow in a region directly, the blood supply to a region increases to supply demand
    PET
  10. sensitivity to a concentration of oxygen in the blood
    fMRI
  11. technique for segregating and measuring differences in white matter and gray matter concentration
    voxel based morphometry
  12. using MRI to measure white matter connectivity between brain regions
    Diffusion tensor imaging (DTI)
  13. The basic requirement in all functional imaging studies is that
    the physiological response must be compared to one or more baseline responses
  14. uses a radioactive tracer injected into the bloodstream. the greater the blood flow in a region, the greater the signal emitted by the tracer in that region.
    Positron emission tomography (PET)
  15. temporal resolution refers to the accuracy with which
    one can measure when a cognitive event is occuring
  16. the spatial resolution refers to the accuracy with which one can measure
    where a cognitive event (a physiological change) is occuring
  17. the component that the fMRI is sensitive to is..
    the amount of deoxyhemoglobin
  18. blood oxygen level dependent contrast; the signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood
    BOLD
  19. three phases of hemodynamic response function
    • 1. initial dip
    • 2. over compensation
    • 3. undershoot
  20. key advantages of the fMRI
    • -better temporal and spatial resolution
    • -does not use radioactivity
  21. characteristics of PET
    • -based on blood volume
    • -involves radioactivity (can only be scanned once)
    • -sensitive to the whole brain
    • -must use a block design
  22. characteristics of fMRI
    • -based on blood oxygen concentration
    • -no radioactivity (able to scan multiple times)
    • -blocked or event related design
    • -some brain areas are hard to image
  23. type of experimental design in functional imaging in which activity in a control task is subtracted from activity in an experimental task
    cognitive subtraction
  24. effect of one variable on another
    interaction
  25. ability to identify a set of tasks that has a particular component in common. the problem of interactions can be reduced
    cognitive conjunction.
  26. measuring associations between brain activity and changes in the variables of interest
    parametric design
  27. measuring the differences in brain activity between two or more conditions
    categorical design
  28. in parametric design a ____ baseline condition is ______ necessary
    separate; not
  29. implies that a region responds to a limited range of stimuli/conditions and that this distinguishes it from the responsiveness of other neighboring regions. not strictly the same as localization
    functional specialization
  30. the way in which different regions communicate with each other. the basic approach is to model how activity in different regions is interdependent.
    functional integration
  31. stimuli that belong together in one condition
    block design
  32. stimuli from two or more conditions are presented randomly interspersed
    event related design
  33. advantage of block design
    the method has more power; that is, it is more able to detect significant but small effects
  34. advantages of even related designs over blocked ones
    they enable a much wider range of experimental designs
  35. mapping of individual differences in brain anatomy onto a standard template
    stereotactic normalization
  36. redistributing brain activity from neighboring voxels to enhance the signal to noise ratio
    smoothing
  37. the most common way of dealing with individual differences is effectively to assume that ..
    they dont exist. or more properly put, individual differences neednt get in the way of making claims about general brain function
  38. locations in the brain defined relative to the atlas of Talairach and Tournoux
    Talairach coordinates
  39. smoothing _____ some of the raw activation level of a given voxel to neighboring voxels
    spreads
  40. difficulty in _____ is that the activity in each voxel is not independent, neighboring voxels tend to have similar activity
    smooooothing
  41. functional imaging gives us a better idea of which ____ may be sufficient for performing a particular task, but not always which regions are ______ and necessary for performing a task
    region; crucial
  42. imaging data imply that a brain region is used in a given task but lesion data suggest that this region is not essential to the task
    disagreement 1 with lesion data
  43. imaging data imply that a brain region is not used in a given task but lesion data suggest that this region is critical to the task
    disagreement 2 with lesion data
  44. a progressive loss of information from semantic memory
    semantic dementia
  45. conceptually based knowledge about the world, including knowledge of people, places, the meaning of objects and words
    semantic memory
  46. patients with damage to the left inferior frontal gyrus do not show clinical symptoms of semantic memory impairments because
    the region is involved in strategic retrieval operations from semantic memory. temporal regions may store the semantic memory and lesions produce impairments
  47. brain imaging can be used to infer the type of _____ and how the stimulus is _______
    stimulus; evaluated

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