Investigating the Infralimbic-Amygdala Circuit During Fear Extinction Learning


Grace O'Brien

Document Type


Publication Date

Summer 2022



JAX Location

In: Student Reports, Summer 2022, The Jackson Laboratory


The Infralimbic (IL) cortex are thought to be involved in fear extinction learning yet the specific projection neurons and the mechanisms they use remain unknown. We proposed that IL neurons that project to the basolateral amygdala (BLA) are crucial for fear extinction learning and subsequent extinction memory retrieval. We used cFos-CreERT2 mice used to identify the neurons active during fear extinction, and our results indicate that the extent of activity in IL-BLA projecting neuron populations correlate with extinction learning and memory retrieval. In an additional experiment, we investigated the role of NMDA receptor subunit Grin2b in these neurons on behavior during extinction by using a gene knockdown approach in Grin2Bfl/fl mice. We found that Grin2B knockdown in IL-to-BLA neurons produced impairments the retrieval of long-term extinction memories. Collectively, these results suggest IL-to-BOA neurons are recruited during fear extinction learning in a Grin2b-depenedent manner.

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