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Dear all, I've read SPM manual which says: 31.3.7 Small volume correction If one has an a priori anatomical hypothesis, eg. in the present example Broca's area will likely be activated during word generation, one may use the small volume correction option. Press the \small volume" button in SPM Interactive (bottom left) window and select a suitable region, e.g., a 30mm sphere with its centre at 44 16 0. The region can also be de ned using mask images derived from previous imaging data. The corrected p-values will change, as shown in Figure 31.11. For example if I got 4 peak voxels at 2nd level analysis, could I perform SVC 4 times separately at those peak voxels in order to report them with smaller FWE p values? If yes, how big should I set the diameter of the SVC? Thanks very much for your time! Yours, Andy On Wed, Jan 8, 2014 at 6:41 AM, MCLAREN, Donald <[log in to unmask]>wrote: > Andy, > > Please see below. > > On Tue, Jan 7, 2014 at 5:08 AM, Andy Yeung <[log in to unmask]> wrote: > >> Dear all, >> >> I notice that there's a button named 'small volume' at the lower left >> corner of the 'Results' window. >> When could I use it? >> > > Small-Volume Correction is used when you want to correct for multiple > comparisons within a smaller area of the brain, rather than correcting for > every voxel in the brain. > > > >> How is it different from performing a 'region of interest' analysis which >> is also another button appeared after choosing a contrast for Results? >> >> > > >> Also, I find the statistical part of SPM very difficult to understand. >> For example, at specify 1st-level, I can choose canonical HRF, FIR, etc... >> are there any courses for beginners dealing with that? I couldn't find >> relevant videos from SPM official web discussing these designs. >> > > I would take a look at SPM8 manual ( > http://www.fil.ion.ucl.ac.uk/spm/doc/manual.pdf), the SPM datasets ( > http://www.fil.ion.ucl.ac.uk/spm/data/), and the book Human Brain > Function (http://www.fil.ion.ucl.ac.uk/spm/doc/books/hbf2/). > > canonical HRF - the typical BOLD response you'd expect - estimates the > amplitude of the BOLD response > > FIR - finite impulse response function - estimates the shape and amplitude > of the BOLD response > > You could also read: > (1) Functional MRI: An Introduction to Methods, by Jezzard; > (2) Functional Magnetic Resonance Imaging, by Huettel > > This website may also be helpful: http://imaging.mrc-cbu.cam.ac.uk/imaging > > > >> Thanks very much in advance! >> >> Yours sincerely, >> Andy >> > >