Before revision: In Fear Conditioning It has been demonstrated in an associative fear conditioning chain, such as CS2 --> CS1 --> US, that extinction of freezing responses to the first-order stimulus (CS1) leads to responding impairments in CS2, but extinction of the second-order stimulus (CS2), does not have any effect on CS1 (Debiec et al.).
After revision: This is too cray-crayIn Fear Conditioning It has been demonstrated in an associative fear conditioning chain, such as CS2 --> CS1 --> US, that extinction of freezing responses to the first-order stimulus (CS1) leads to responding impairments in CS2, but extinction of the second-order stimulus (CS2), does not have any effect on CS1 (Debiec et al.).