Abstract

In this chapter I review published studies exploring grey matter differences in the brains of synaesthetes. I examine how these structural imaging results might inform current theories about the neural mechanisms of synaesthesia. Since many voxel-based morphometry studies have focussed on grapheme-colour synaesthesia, the emphasis of this chapter will reflect this, and so I will show our current knowledge about GM differences in grapheme-colour synaesthetes in particular. I also provide a critical discussion of the kinds of limitations found in previous approaches to studying synaesthetic GM differences, and I discuss future perspectives and challenges that structural neuroimaging research in synaesthesia will face.