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Forming competing fear learning and extinction memories in adolescence makes fear difficult to inhibit.
Learn Mem. 2015 Nov; 22(11):537-43.LM

Abstract

Fear inhibition is markedly impaired in adolescent rodents and humans. The present experiments investigated whether this impairment is critically determined by the animal's age at the time of fear learning or their age at fear extinction. Male rats (n = 170) were tested for extinction retention after conditioning and extinction at different ages. We examined neural correlates of impaired extinction retention by detection of phosphorylated mitogen-activated protein kinase immunoreactivity (pMAPK-IR) in several brain regions. Unexpectedly, adolescent rats exhibited good extinction retention if fear was acquired before adolescence. Further, fear acquired in adolescence could be successfully extinguished in adulthood but not within adolescence. Adolescent rats did not show extinction-induced increases in pMAPK-IR in the medial prefrontal cortex or the basolateral amygdala, or a pattern of reduced caudal central amygdala pMAPK-IR, as was observed in juveniles. This dampened prefrontal and basolateral amygdala MAPK activation following extinction in adolescence occurred even when there was no impairment in extinction retention. In contrast, only adolescent animals that exhibited impaired extinction retention showed elevated pMAPK-IR in the posterior paraventricular thalamus. These data suggest that neither the animal's age at the time of fear acquisition or extinction determines whether impaired extinction retention is exhibited. Rather, it appears that forming competing fear conditioning and extinction memories in adolescence renders this a vulnerable developmental period in which fear is difficult to inhibit. Furthermore, even under conditions that promote good extinction, the neural correlates of extinction in adolescence are different than those recruited in animals of other ages.

Authors+Show Affiliations

School of Psychology, UNSW Australia, Sydney, New South Wales 2052, Australia k.baker@unsw.edu.au.School of Psychology, UNSW Australia, Sydney, New South Wales 2052, Australia.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26472643

Citation

Baker, Kathryn D., and Rick Richardson. "Forming Competing Fear Learning and Extinction Memories in Adolescence Makes Fear Difficult to Inhibit." Learning & Memory (Cold Spring Harbor, N.Y.), vol. 22, no. 11, 2015, pp. 537-43.
Baker KD, Richardson R. Forming competing fear learning and extinction memories in adolescence makes fear difficult to inhibit. Learn Mem. 2015;22(11):537-43.
Baker, K. D., & Richardson, R. (2015). Forming competing fear learning and extinction memories in adolescence makes fear difficult to inhibit. Learning & Memory (Cold Spring Harbor, N.Y.), 22(11), 537-43. https://doi.org/10.1101/lm.039487.114
Baker KD, Richardson R. Forming Competing Fear Learning and Extinction Memories in Adolescence Makes Fear Difficult to Inhibit. Learn Mem. 2015;22(11):537-43. PubMed PMID: 26472643.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Forming competing fear learning and extinction memories in adolescence makes fear difficult to inhibit. AU - Baker,Kathryn D, AU - Richardson,Rick, Y1 - 2015/10/15/ PY - 2015/07/02/received PY - 2015/08/21/accepted PY - 2015/10/17/entrez PY - 2015/10/17/pubmed PY - 2016/7/22/medline SP - 537 EP - 43 JF - Learning & memory (Cold Spring Harbor, N.Y.) JO - Learn Mem VL - 22 IS - 11 N2 - Fear inhibition is markedly impaired in adolescent rodents and humans. The present experiments investigated whether this impairment is critically determined by the animal's age at the time of fear learning or their age at fear extinction. Male rats (n = 170) were tested for extinction retention after conditioning and extinction at different ages. We examined neural correlates of impaired extinction retention by detection of phosphorylated mitogen-activated protein kinase immunoreactivity (pMAPK-IR) in several brain regions. Unexpectedly, adolescent rats exhibited good extinction retention if fear was acquired before adolescence. Further, fear acquired in adolescence could be successfully extinguished in adulthood but not within adolescence. Adolescent rats did not show extinction-induced increases in pMAPK-IR in the medial prefrontal cortex or the basolateral amygdala, or a pattern of reduced caudal central amygdala pMAPK-IR, as was observed in juveniles. This dampened prefrontal and basolateral amygdala MAPK activation following extinction in adolescence occurred even when there was no impairment in extinction retention. In contrast, only adolescent animals that exhibited impaired extinction retention showed elevated pMAPK-IR in the posterior paraventricular thalamus. These data suggest that neither the animal's age at the time of fear acquisition or extinction determines whether impaired extinction retention is exhibited. Rather, it appears that forming competing fear conditioning and extinction memories in adolescence renders this a vulnerable developmental period in which fear is difficult to inhibit. Furthermore, even under conditions that promote good extinction, the neural correlates of extinction in adolescence are different than those recruited in animals of other ages. SN - 1549-5485 UR - https://www.unboundmedicine.com/medline/citation/26472643/Forming_competing_fear_learning_and_extinction_memories_in_adolescence_makes_fear_difficult_to_inhibit_ L2 - https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/26472643/ DB - PRIME DP - Unbound Medicine ER -