A ventral hippocampus-basolateral amygdala circuit regulates the unconditioned stimulus retrieval-induced reconsolidation of remote fear memory

CA1 (Field CA1) UBERON:0003881 projects to BLA (basal amygdaloid nucleus) UBERON:0002887 · Rat

A retrograde AAV driving mCherry under a CaMKIIa promoter was placed in the BLA and labelled mCherry-positive cells in ventral CA1, showing that excitatory vCA1 neurons send axons to the BLA; a subset of these labelled cells co-expressed c-Fos after unconditioned-stimulus retrieval of remote fear memory.

Fig. 4b, 4d; Methods (retrograde non-transsynaptic tracing)

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PL (Prelimbic area) UBERON:8440032 projects to BLA (basal amygdaloid nucleus) UBERON:0002887 · Rat

Retrograde CaMKIIa-mCherry virus injected in the BLA labelled neurons in the prelimbic cortex, indicating a PL-to-BLA excitatory projection; these labelled PL cells showed increased c-Fos after conditioned-stimulus retrieval of remote fear memory.

Fig. 4b, 4c

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CA1 (Field CA1) UBERON:0003881 projects to BLA (basal amygdaloid nucleus) UBERON:0002887 · Rat

After injecting a CaMKIIa-GCaMP6s virus into ventral CA1, labelled glutamatergic axon terminals were found in the BLA, where an optical fibre recorded their calcium signals, confirming an anterogradely traced vCA1-to-BLA pathway.

Fig. 5e-f

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LC (Locus ceruleus) UBERON:0002148 projects to BLA (basal amygdaloid nucleus) UBERON:0002887 · Rat

Retrograde virus injected into the BLA labelled locus coeruleus neurons, and in a separate experiment a retrograde Cre virus in the BLA combined with a TH-dependent construct in the LC allowed selective targeting of LC neurons projecting to the BLA; LC-labelled cells were c-Fos positive after both CS and US retrieval of remote fear memory.

Fig. 4b, 4e; Fig. 6i

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