Neural Circuits & Behavior Process Report // Bianca Silva - A thalamo-amygdalar circuit underlies remote fear memory attenuation

Despite the rising prevalence of trauma-related disorders and the consequent need to better understand how long-lasting traumatic memories are attenuated, the brain areas supporting this process remain largely unknown. Here, we show – using real-time fiber photometry recordings, bidirectional chemogenetic manipulations and functional circuit mapping in vivo – that the ventromedial thalamus (VMT) mediates remote fear memory attenuation in the mouse. During experimental extinction of remote fear memories, the VMT increases in activity before the end of freezing bouts. Correspondingly, inhibiting VMT activity impairs, while activating ameliorates remote fear attenuation. VMT outputs to the basal amygdala (BA) mediate this mitigating effect, stipulating that the VMT provides safety signals to the BA. These findings identify a critical node for remote fear memory attenuation and foster our understanding of traumatic memory processing