Brainstem specific warping improves locus coeruleus functional imaging in humans

The locus coeruleus (LC), a specific brainstem structure containing noradrenergic neurons [1], has recently attracted much interest because the LC is involved in attention processes and attention modulations [2]. 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 leads to an accurate match of the group averaged LC localisation.