CLOCK and Anxiety: Even though studies revealed mixed outcomes on the effect of daytime on anxiety-like behaviors (Richetto et al., 2018; Meseguer Henarejos et al., 2020; Tsao et al., 2022), our results strongly support the view that time of day is a major factor in the regulation of anxiety-like behavior, and the deletion of clock genes in the striatum appears to attenuate this effect.