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And do a subtraction in order to get a difference

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Unformatted text preview: er & Raichle, Images of Mind Other challenges: Like I said, it is a very noisy technique. So must take average pattern of activity. and do a subtraction in order to get a difference between and use that to compare results. Often must average other a large group. Most studies don't take into account that the great variety in brains. Functional images Analyzing fMRI Data! ~2s ROI Time Course fMRI Signal (% change) Time Condition Statistical Map superimposed on anatomical MRI image Time Region of interest (ROI) ~ 5 min Collecting images every two seconds and then the conditions switch but still collecting and may find signal is much more intense in one condition than the other condition, etc etc. Basic idea behind fMRI, and for the most part works really well, but can also have a lot of bad fMRI as well... A cautionary tale on neuroimaging Study on taking the perspective of somebody else. So this was a study that a Post-doc of mine was studying, so in this, he got significant activity in the medial portion of the brain. The subject wasn't a human, but it was a dead salmon and can see functional activity in the dead portion of the salmon's medial brain. So it turns out, that because there is so much noise in these measurement, that even if you think randomly, you can still "significant" measurements. But the reason to run this study, is because must be very careful about the statistical thresholds. Neural Correlates of Interspecies Perspective Taking in the Post-Mortem Atlantic Salmon: An Argument for Multiple Comparisons Correction Bennett, Baird, Miller, & Wolford (2010) Journal of Serendipitous & Unexpected Results A cautionary tale on neuroimaging Won Ig Nobel Away. Geprgia "Peaches" Neuroimaging Studies! Advantage: neural activity in normal brain; localize specific cognitive processes; high spatial resolution! Disadvantage: indirect measure of neural activity; poor temporal resolution! Relies on hemodynamic response. Anatomical Study of the Brain Functional Study of the Brain...
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