CHAT and Anxiety: The habenula has been described as an anti-reward center, though this characterization has been predominantly informed by the activity of LHb neurons because of their response to aversive stimuli and negative reward prediction error (Hikosaka, 2010; Proulx et al., 2014) and to a lesser extent the ventral MHb ChAT+ neurons, which have been implicated in anxiety (Cho et al., 2019; Mathuru et al., 2013; Seigneur et al., 2018; Yamaguchi et al., 2013) and aversion (Buolos et al., 2020; Frahm et al., 2011; McLaughlin et al., 2017; Morton et al., 2018; Choi et al., 2021).