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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
(% change) Time Condition Statistical Map
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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- Fall '11