Brainstem Specific Warping Improves Locus Coeruleus Functional Imaging in Humans

Evelyne Balteau¹, Christina Schmidt¹, Pierre Maquet¹, Christophe Phillips¹

The locus coeruleus (LC), a specific but small brainstem structure, has recently attracted much interest because the LC is involved in attention processes and attention modulations. The accurate localisation of LC activity with functional imaging in group studies was questioned since the LC is anatomically difficult to localise on standard functional (EPI) or structural (T1-weighted) MR images. We aim to show here that standard EPI-based normalisation leads to approximate alignment of the LC across subjects, and that using a T1-based brainstem specific normalisation improves the match of the group averaged LC localisation, in line with an independent LC template.