Competition between engrams influences fear memory formation and recall

#TODO

• Typical setup: two different CS fear conditionings, separated by 1.5, 6, 18 or 24 hours
• Results
• FC2 enhanced if follows FC1 by 1.5-6 hours, not 18-24 hours
• Event 1 &2 collalocated to same engram if separated by 6 hours, not 24
• Extinguishing CS2 caused a decrease in response to CS1 if fear conditioning separated by 6 hours, not 24
• Fear conditioning increases CREB that lasts 1.5-6 hours, not 18-24 hours
• Exciting Engram 1 artificially after 24 hours before FC2 coallocates to Event 2
• Inhibiting overlapping engram impairs CS1, CS2 overlap
• To separate memories (conditioned within 6 hours), infected before CS1 then inhibited before FC2. Event two disrupted even when mice tested without suppression of FC1 engram. No effect if FC1 and FC2 separated by 24 hours.

Research Questions

Experiments

Exp 1