TITLE:
Contextual Fear Extinction and Re-Extinction in Carioca High- and Low-Conditioned Freezing Rats
AUTHORS:
Vitor de Castro Gomes, Laura Andrea León, Daniel Mograbi, Fernando Cardenas, Jesus Landeira-Fernandez
KEYWORDS:
Genetic Selection, Freezing Response, Fear Extinction
JOURNAL NAME:
World Journal of Neuroscience,
Vol.4 No.3,
June
26,
2014
ABSTRACT: We recently reported two novel breeding lines of rats known as Carioca
High- and Low-conditioned Freezing (CHF and CLF), based on defensive freezing
responses to contextual cues previously associated with electric footshock. The
present study used animals of the 8th generation of our selective
breeding program to investigate both contextual fear extinction and
re-extinction. The results consistently showed that CHF animals froze more than
CLF animals. Long extinction training was able to extinguish phenotypic
differences between lines, but the divergence was restored after just one fear
reacquisition training session. These differences disappeared again during
re-extinction training. The possible neural mechanisms involved in these two
types of learning are discussed.