Cited by 417Memory and Neural MechanismsStress Responses and CortisolNeurotransmitter Receptor Influence on Behavior

Estrous cycle phase and gonadal hormones influence conditioned fear extinction

Open access
Milad, M.R., Igoe, S.A., Lebron-Milad, K., Novales, J.E.·2009·Neuroscience

Abstract

Gonadal hormones modulate fear acquisition, but less is known about the influence of gonadal hormones on fear extinction. We assessed sex differences and the influence of gonadal hormone fluctuations and exogenous manipulations of estrogen and progesterone on acquisition, extinction learning and extinction recall in a 3 day auditory fear conditioning and extinction protocol. Experiments were conducted on males and naturally cycling female rats. Regarding female rats, significant differences in fear extinction were observed between subgroups of females, depending on their phase of the estrous cycle. Extinction that took place during the proestrus (high estrogen/progesterone) phase was more fully consolidated, as evidenced by low freezing during a recall test. This suggests that estrogen and/or progesterone facilitate extinction. In support of this, injection of both estrogen and progesterone prior to extinction learning in female rats during the metestrus phase of the cycle (low estrogen/progesterone) facilitated extinction consolidation, and blockade of estrogen and progesterone receptors during the proestrus phase impaired extinction consolidation. When comparing male to female rats without consideration of the estrous cycle phase, no significant sex differences were observed. When accounting for cycle phase in females, sex differences were observed only during extinction recall. Female rats that underwent extinction during the metestrus phase showed significantly higher freezing during the recall test relative to males. Collectively, these data suggest that gonadal hormones influence extinction behavior possibly by influencing the function of brain regions involved in the consolidation of fear extinction. Moreover, the elevated fear observed in female relative to male rats during extinction recall suggests that gonadal hormones may in part play a role in the higher prevalence of anxiety disorders in women.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1016/j.neuroscience.2009.09.011

Cites

62 of 62 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

1 of the 63 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Authors
Milad, M. R., Igoe, S. A., Lebron-Milad, K., & Novales, J. E.
Affiliations
Harvard University (US)
Corresponding author
Milad, M.R.
Venue
Neuroscience
Publisher
Elsevier BV
Published
2009-12
Volume
164
Issue
3
Pages
887-895
ISSN
0306-4522 (ISSN-L)
OpenAlex
W1998244790
Cited by
417
References
63
Citations by year
2026: 18 · 2025: 26 · 2024: 27 · 2023: 32 · 2022: 38 · 2021: 24 · 2020: 37 · 2019: 35 · 2018: 27 · 2017: 25 · 2016: 32 · 2015: 22 · 2014: 24 · 2013: 17 · 2012: 13
FWCI
5.00
Type
journal article
Language
en
Open access
Locations
  • Neuroscience (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute of Mental Health (K01 MH080346)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
  • Life Sciences › Neuroscience › Behavioral Neuroscience › Stress Responses and Cortisol
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neurotransmitter Receptor Influence on Behavior
Keywords
fear extinction, estrous cycle, gonadal hormones, estrogen, progesterone, auditory fear conditioning, sex differences, extinction consolidation, extinction recall, estrogen receptor blockade, rats
MeSH terms
Animals, Anxiety Disorders, Brain, Conditioning, Psychological, Estrogens, Extinction, Psychological, Fear, Female, Learning, Male, Metestrus, Neuropsychological Tests, Photic Stimulation, Proestrus, Progesterone, Receptors, Estrogen, Sex Characteristics, Gonadal Steroid Hormones, Testosterone, Rats, Sprague-Dawley, Estrous Cycle, Freezing Reaction, Cataleptic, Rats

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review