> In this situation, in the same cluster-wise threshold (p<.05), can I use a lower
> voxel-wise threshold (p<.015) and a higher spatial threshold (e.g., 20) based
> on the AlphaSim?
Sure you can do that. In fact you use any combination of voxel-wise p-threshold and cluster size threshold you feel comfortable with. For reference you can cite the following:
Forman SD, Cohen JD, Fitzgerald M, Eddy WF, Mintun MA, Noll DC (1995): Improved assessment of significant activation in functional magnetic resonance imaging (fMRI): use of a cluster-size threshold. Magn Reson Med 33: 636-647.
Ziad S Saad, Gang Chen, Richard C Reynolds, Patricia P Christidis, Kenneth R Hammett, Patrick S F Bellgowan, Robert W Cox (2007), Functional imaging analysis contest (FIAC) analysis according to AFNI and SUMA. Human Brain Mapping, Volume 27 Issue 5, Pages 417 - 424.
Gang