So, what is meta-analysis?
Meta-analysis often combines summary statistics like effect sizes across
a population of studies or
group of studies based on reported values in the publications themselves.
So when you're imaging the most common practice is to analyze reported
activation coordinates from published tables.
This is called coordinate-based meta-analysis, and the coordinates
are usually reported in standardized space in virtually every study or most studies.
So, we get a pretty good sample of overture from this, and
the coordinates usually reflect the peek statistic values.
And they are often reported in Montreal Neurologic Institutes base MNI space, or
what's called Talairach space,
which is an approximation that's similar to MNI space but less precisely defined.
So these x, y, and z coordinates refer here to coordinates in brain space.
The 0 point is the anterior commissure,
the small commissure that connects the hemispheres.
And you can see on the structural scan and mark it off, and x is left to right.
Y is posterior to anterior.
And z is inferior to superior by convention.
So, we can take all these reported coordinates and
put them into a series of studies.
So, coordinate-based meta-analysis will turn this collection of coordinates across
the brain into a picture of where the consistent findings,
are and where there's a significant density of
reported coordinates that exceed what you expect by chance.