EEG

20. Sensing Techniques-Cat Scans ordinary x-rays look at bone, other matter its a composite picture- doesn�t isloate a single slice To isolate a single slice, trangulate in using lots of scans and use a computer to reconstruct the slice.ordinary x-rays look at bone, other matter its a composite picture- doesn�t isloate a single slice To isolate a single slice, trangulate in using lots of scans and use a computer to reconstruct the slice.

21. Sensing Techniques-Cat Scans ordinary x-rays look at bone, other matter its a composite picture- doesn�t isloate a single slice To isolate a single slice, trangulate in using lots of scans and use a computer to reconstruct the slice.ordinary x-rays look at bone, other matter its a composite picture- doesn�t isloate a single slice To isolate a single slice, trangulate in using lots of scans and use a computer to reconstruct the slice.

22. Sensing Techniques-Cat Scans Cat Scans use x-rays to show structures Really precise maps Hard to determine functions

24. Sensing Techniques-PET Radioactive element decays, gives off positron Positron moves a short distance and gives off two gamma rays in opposite directions

25. Sensing Techniques-PET Because 180 degrees apart, can isolate a slice of the brain Detectors detect arriving gamma rays, and because of the timeing involved they can figure out where the original decay was Radioactive materials carried by glucose- used by brain when it it working More glucose = more brain activity An indirect measure of brain functioning- but studies brain functioning none-the-lessBecause 180 degrees apart, can isolate a slice of the brain Detectors detect arriving gamma rays, and because of the timeing involved they can figure out where the original decay was Radioactive materials carried by glucose- used by brain when it it working More glucose = more brain activity An indirect measure of brain functioning- but studies brain functioning none-the-less

26. PET Scans Left scan: Eyes closed Middle scan: White light Right scan: Complex scene See increasing activity in Occipital lobesLeft scan: Eyes closed Middle scan: White light Right scan: Complex scene See increasing activity in Occipital lobes

27. PET Scans Episodic Task: remembering an experience that happened 40 years ago Semantic task: thinking about the history of astronomy that was learned 40 years ago Red:above-average blood flow, yellow: average blood flow, green: below-average blood flow. Difference: Red: greater activation during episodic task, Green: greadter activation during semantic taskEpisodic Task: remembering an experience that happened 40 years ago Semantic task: thinking about the history of astronomy that was learned 40 years ago Red:above-average blood flow, yellow: average blood flow, green: below-average blood flow. Difference: Red: greater activation during episodic task, Green: greadter activation during semantic task

28. PET Scans

39. Sensing Techniques-fMRI Functional Magnetic Nuclear Resonance Imaging Similar to Pet, uses radio frequency information given off by water Gives better time (6 seconds) and spatial (2 mm) resolution than Pet or Cat scans Technology still under revision Slight danger to subjects Expensive ($300 an hour)

40. fMRI Method

41. MRI Scans

42. MRI Scans

50. Summary Appropriate technology depends on question ERP has good temporal resolution CAT, Pet, MRI have good to fair spatial resolution, only PET has any functional capture fMRI has reasonably good spatial, reasonably good temporal, but is expensive