A new thalamo-cortical-amygdala circuit is involved in processing a natural auditory alarm cue

Abstract

15Animals use auditory cues generated by defensive responses of others to detect 16 impending danger. Here we identify a neural circuit in rats involved in the 17 detection of one such auditory cue, the cessation of movement-evoked sound 18 resulting from freezing. This circuit comprises the dorsal sub-nucleus of the 19 medial geniculate body (MGD) and downstream areas, the ventral area of the 20 auditory cortex (VA) and the lateral amygdala (LA). This study suggests a role for 21 the auditory offset pathway in processing a natural sound cue of threat. 22 23 595

Single cell plasticity and population coding stability in auditory thalamus upon associative learning

“…Furthermore, 85% ± 2% of amygdala-projecting MGB neurons ( Figures 4D and S8A, N = 6 mice) were positive for the higher-order MGB area marker calretinin (Lu et al, 2009), suggesting that calretinin is a highly prevalent but not exclusive marker of BLA-projecting MGB neurons. To test if MGB→BLA projection neurons are necessary for fear learning (Antunes and Moita, 2010;Apergis-Schoute et al, 2005;Han et al, 2011;Pereira et al, 2019), we specifically expressed the inhibitory opsin ArchT in MGB→BLA projectors ( Figures S9A-S9D). Inhibition of MGB→BLA projectors during CS-US pairing on the conditioning day had no effect on fear acquisition ( Figures S9E-S9G, mean freezing during the last two CS+ presentations, control: 50% ± 5% freezing, ArchT: 45% ± 8% freezing, p > 0.05, Mann-Whitney Test).…”